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2024,43(3):1-8
, DOI: 10.13300/j.cnki.hnlkxb.2024.03.001
Abstract:
This article derived wisdom from the long history and explored how to integrate the traditional farming civilization with the notion of ecological low-carbon to achieve sustainable development in agriculture on the journey towards modernization with Chinese characteristics.It was proposed that four principles including balancing the food production and the development of agriculture with ecological low-carbon， pursuing a synergistic approach between common prosperity and the development of agriculture with ecological low-carbon， continuing the legacy of farming civilization and the development of agriculture with ecological low-carbon， and composing a way to respect for nature and protect the development of agriculture with ecological low-carbon should be followed in developing agriculture with ecological low-carbon under the background of modernization with Chinese characteristics.In the future， it is necessary to construct a collaborative mechanism for the development and application of agriculture technology with ecological low-carbon， improve the market integration and value realization pathways of agriculture with ecological low-carbon， establish a system for the integration and passing on of farming techniques and agriculture with ecological low-carbon， and form a framework for the coordinated development of natural resources and agriculture with ecological low-carbon.
This article derived wisdom from the long history and explored how to integrate the traditional farming civilization with the notion of ecological low-carbon to achieve sustainable development in agriculture on the journey towards modernization with Chinese characteristics.It was proposed that four principles including balancing the food production and the development of agriculture with ecological low-carbon， pursuing a synergistic approach between common prosperity and the development of agriculture with ecological low-carbon， continuing the legacy of farming civilization and the development of agriculture with ecological low-carbon， and composing a way to respect for nature and protect the development of agriculture with ecological low-carbon should be followed in developing agriculture with ecological low-carbon under the background of modernization with Chinese characteristics.In the future， it is necessary to construct a collaborative mechanism for the development and application of agriculture technology with ecological low-carbon， improve the market integration and value realization pathways of agriculture with ecological low-carbon， establish a system for the integration and passing on of farming techniques and agriculture with ecological low-carbon， and form a framework for the coordinated development of natural resources and agriculture with ecological low-carbon.
2024,43(3):9-16
, DOI: 10.13300/j.cnki.hnlkxb.2024.03.002
Abstract:
Agricultural carbon trading is an essential tool that facilitates the transition from traditional to low-carbon agriculture， offering significant potential to enhance farmers’ income. At present， notable progress has been achieved in China’s pilot agricultural carbon trading initiatives. However， how to achieve widespread participation among farmers and effectively enhance their income remains a key issue that needs to be urgently addressed. To synergistically propel the attainment of the “Dual-carbon” objectives and the realization of common prosperity， by examining the typical scenarios of agricultural carbon trading pilots and delineating the process of agricultural carbon trading， this study elucidated the mechanisms through which agricultural carbon trading promotes farmers’ income. Additionally， we categorized agricultural carbon trading projects based on farmers’ participation demands and income potential， delving into the real-world challenges faced by different types of projects and offering corresponding countermeasures and recommendations. The study revealed that the benefits of farmers’ income enhancement stem from transfer payments from regulatory agencies， input contributions from farmers， organization and guidance from intermediary institutions， and product purchases from consumers. Therefore， it is imperative to improve the policy support system for agricultural carbon trading， strengthen capacity building for agricultural carbon trading， stimulate social service vitality in agricultural carbon trading， and optimize the mechanism for sharing benefits of farmers’ income enhancement.
Agricultural carbon trading is an essential tool that facilitates the transition from traditional to low-carbon agriculture， offering significant potential to enhance farmers’ income. At present， notable progress has been achieved in China’s pilot agricultural carbon trading initiatives. However， how to achieve widespread participation among farmers and effectively enhance their income remains a key issue that needs to be urgently addressed. To synergistically propel the attainment of the “Dual-carbon” objectives and the realization of common prosperity， by examining the typical scenarios of agricultural carbon trading pilots and delineating the process of agricultural carbon trading， this study elucidated the mechanisms through which agricultural carbon trading promotes farmers’ income. Additionally， we categorized agricultural carbon trading projects based on farmers’ participation demands and income potential， delving into the real-world challenges faced by different types of projects and offering corresponding countermeasures and recommendations. The study revealed that the benefits of farmers’ income enhancement stem from transfer payments from regulatory agencies， input contributions from farmers， organization and guidance from intermediary institutions， and product purchases from consumers. Therefore， it is imperative to improve the policy support system for agricultural carbon trading， strengthen capacity building for agricultural carbon trading， stimulate social service vitality in agricultural carbon trading， and optimize the mechanism for sharing benefits of farmers’ income enhancement.
2024,43(3):17-26
, DOI: 10.13300/j.cnki.hnlkxb.2024.03.003
Abstract:
In promoting the realization of the “Dual carbon” goals， the agricultural sector holds tremendous potential. However， the actual progress in unlocking this potential has been relatively slow. Currently， China’s agriculture is at a crucial juncture in its low-carbon transformation and urgently needs to define devolping mechanisms to steadily advance low-carbon agriculture in the new era. Based on this foundation， this paper aimed to conduct an in-depth analysis of the complex issues that hinder the sustainable development of low-carbon agriculture in our country， and to clarify the theoretical underpinnings of these issues. Through this analysis， the research seeked to explore a pathway for the development of low-carbon agriculture that aligns with our national conditions. This paper examineed a vast amount of literature to uncover the specific challenges facing China’s agriculture in its low-carbon transition， theoretically analyzed the key bottlenecks during this transformation， and identified opportunities for the stable development of low-carbon agriculture in China. The research indicated that significant pressures in the agricultural sector during the transition towards a low-carbon model. These pressures were primarily characterized by the absence of mechanisms to convert low-carbon concepts into new avenues for value creation. At the same time， agricultural operators and top-level designers still maintained the inertia of the high-carbon era development models. It is essential to reevaluate the roles of the market and the government in China’s transition to low-carbon agriculture， to seize the real opportunities under the “dual carbon” objectives， and to leverage the “Market-Government” co-construction mechanism. This approach aims to achieve low-carbon agricultural development targets that balance economic efficiency， social benefits， and ecological gains.
In promoting the realization of the “Dual carbon” goals， the agricultural sector holds tremendous potential. However， the actual progress in unlocking this potential has been relatively slow. Currently， China’s agriculture is at a crucial juncture in its low-carbon transformation and urgently needs to define devolping mechanisms to steadily advance low-carbon agriculture in the new era. Based on this foundation， this paper aimed to conduct an in-depth analysis of the complex issues that hinder the sustainable development of low-carbon agriculture in our country， and to clarify the theoretical underpinnings of these issues. Through this analysis， the research seeked to explore a pathway for the development of low-carbon agriculture that aligns with our national conditions. This paper examineed a vast amount of literature to uncover the specific challenges facing China’s agriculture in its low-carbon transition， theoretically analyzed the key bottlenecks during this transformation， and identified opportunities for the stable development of low-carbon agriculture in China. The research indicated that significant pressures in the agricultural sector during the transition towards a low-carbon model. These pressures were primarily characterized by the absence of mechanisms to convert low-carbon concepts into new avenues for value creation. At the same time， agricultural operators and top-level designers still maintained the inertia of the high-carbon era development models. It is essential to reevaluate the roles of the market and the government in China’s transition to low-carbon agriculture， to seize the real opportunities under the “dual carbon” objectives， and to leverage the “Market-Government” co-construction mechanism. This approach aims to achieve low-carbon agricultural development targets that balance economic efficiency， social benefits， and ecological gains.
2024,43(3):27-38
, DOI: 10.13300/j.cnki.hnlkxb.2024.03.004
Abstract:
This article analyzed the logic of reducing application of fertilizer under the constraint of plot scale based on the theory of induced technological change. The data about maize farmers in seven provinces of China obtained from 2020 China Rural Revitalization Survey （CRRS） and the 2SLS model were used to analyze the impact of plot size on fertilizer input. The results of empirical studies showed that expanding the plot scale reduced the input intensity of fertilizer and improved the input efficiency of fertilizer. The results of heterogeneity analyses showed that the expansion of plot scale by large-scale farmers had a greater impact on reducing application of fertilizer compared with small-scale farmers. The impact of expanding plot scale on fertilizer input was even more pronounced in term of farmers with higher input intensity and lower input efficiency of fertilizer. The results of analyzing mechanism showed that replacing agricultural labor with mechanical operations was a mechanism for reducing the expansion of plot scale and promoting the reduced application of fertilizer.
This article analyzed the logic of reducing application of fertilizer under the constraint of plot scale based on the theory of induced technological change. The data about maize farmers in seven provinces of China obtained from 2020 China Rural Revitalization Survey （CRRS） and the 2SLS model were used to analyze the impact of plot size on fertilizer input. The results of empirical studies showed that expanding the plot scale reduced the input intensity of fertilizer and improved the input efficiency of fertilizer. The results of heterogeneity analyses showed that the expansion of plot scale by large-scale farmers had a greater impact on reducing application of fertilizer compared with small-scale farmers. The impact of expanding plot scale on fertilizer input was even more pronounced in term of farmers with higher input intensity and lower input efficiency of fertilizer. The results of analyzing mechanism showed that replacing agricultural labor with mechanical operations was a mechanism for reducing the expansion of plot scale and promoting the reduced application of fertilizer.
2024,43(3):39-50
, DOI: 10.13300/j.cnki.hnlkxb.2024.03.005
Abstract:
Synchronizing the food security strategy with the goal of “carbon peaking and carbon neutrality” is the key to accelerate the pace of agricultural and rural modernization and the construction of a strong agricultural country. To promote the synchronization of the food security strategy with the “Dual-carbon” objective， this study， based on the perspective of food security， explained the scientific connotation of eco-low-carbon agriculture， clarified the dialectical relationship between food security and eco-low-carbon agriculture， analyzed the problems and challenges faced by eco-low-carbon agriculture under the food security strategy， and put forward the development strategies and the promotion paths. The study revealed that， under the guidance of “all-encompassing approach to food”， “large-scale industrial view” and “view of big agriculture”， ecological low-carbon agriculture involves the ecological low-carbon of the entire food category， industrial process， and life link. Food security is the bottome-line requirement for the development of ecological low-carbon agriculture， and ecological low-carbon agriculture represents the true meaning of sustainable food security. At present， the development of ecological low-carbon agriculture is facing various practical difficulties， including natural resource constraints， scientific and technological bottlenecks， small-scale agricultural production patterns， the limitations of the residents’ concepts and others， It is urgent to explore the effective paths for expanding water and land resources， applying technological innovations， and improving the quality of residents， so as to promote ecological low-carbon agriculture and achieve the goal of “storing grain in the land”， “storing food in technology” and “storing food in the people”.
Synchronizing the food security strategy with the goal of “carbon peaking and carbon neutrality” is the key to accelerate the pace of agricultural and rural modernization and the construction of a strong agricultural country. To promote the synchronization of the food security strategy with the “Dual-carbon” objective， this study， based on the perspective of food security， explained the scientific connotation of eco-low-carbon agriculture， clarified the dialectical relationship between food security and eco-low-carbon agriculture， analyzed the problems and challenges faced by eco-low-carbon agriculture under the food security strategy， and put forward the development strategies and the promotion paths. The study revealed that， under the guidance of “all-encompassing approach to food”， “large-scale industrial view” and “view of big agriculture”， ecological low-carbon agriculture involves the ecological low-carbon of the entire food category， industrial process， and life link. Food security is the bottome-line requirement for the development of ecological low-carbon agriculture， and ecological low-carbon agriculture represents the true meaning of sustainable food security. At present， the development of ecological low-carbon agriculture is facing various practical difficulties， including natural resource constraints， scientific and technological bottlenecks， small-scale agricultural production patterns， the limitations of the residents’ concepts and others， It is urgent to explore the effective paths for expanding water and land resources， applying technological innovations， and improving the quality of residents， so as to promote ecological low-carbon agriculture and achieve the goal of “storing grain in the land”， “storing food in technology” and “storing food in the people”.
2024,43(3):51-64
, DOI: 10.13300/j.cnki.hnlkxb.2024.03.006
Abstract:
To promote the protection of cultivated land and green and low-carbon development in the Yangtze River Economic Belt， this study employed methods such as the equivalent factor method and the environmental cost method to quantify the ecological service value and negative externalities of cultivated land. By cakulating the ecological footprint and ecological carrying capacity of cultivated land resources， the 11 provinces in the Yangtze River Economic Belt were categorized into surplus areas， balanced areas， and deficit areas. The ecological spillover value of cultivated land was assessed， and its spatiotemporal variation characteristics were explored. The results showed that： Firstly， from 2011 to 2021， the total ecological value of cultivated land in the Yangtze River Economic Belt showed an increasing trend， rising from 367.037 billion yuan to 466.155 billion yuan. The ecological spillover value of cultivated land also gradually increased， from 135.382 billion yuan to 197.077 billion yuan. Secondly， cultivated land resources in the Yangtze River Economic Belt were in a surplus state overall. The ecological value of cultivated land exhibited an “east-low and west-high” pattern. Sichuan had the highest ecological value and surplus quantity of cultivated land， while Shanghai had the lowest ecological value. Thirdly， from 2011 to 2021， the cultivated land ecological values of Zhejiang and Shanghai were deficit， Sichuan was in the ecological high-surplus area， Chongqing and Guizhou were in a balanced state， and Jiangxi， Anhui， and Jiangsu showed no significant changes in the ecological surplus or deficit of cultivated land. Yunnan and Hubei provinces saw an increase in the ecological surplus of cultivated land， while Hunan province experienced a decrease. Based on this， each province in the Yangtze River Economic Belt should make full use of its own resources and advantages， formulate and implement adaptive cultivated land protection strategies， so as to promote the sustainable use of cultivated land resources， and contribute to realize the goal of “ecological priority， green and low-carbon development” in the Yangtze River Economic Belt.
To promote the protection of cultivated land and green and low-carbon development in the Yangtze River Economic Belt， this study employed methods such as the equivalent factor method and the environmental cost method to quantify the ecological service value and negative externalities of cultivated land. By cakulating the ecological footprint and ecological carrying capacity of cultivated land resources， the 11 provinces in the Yangtze River Economic Belt were categorized into surplus areas， balanced areas， and deficit areas. The ecological spillover value of cultivated land was assessed， and its spatiotemporal variation characteristics were explored. The results showed that： Firstly， from 2011 to 2021， the total ecological value of cultivated land in the Yangtze River Economic Belt showed an increasing trend， rising from 367.037 billion yuan to 466.155 billion yuan. The ecological spillover value of cultivated land also gradually increased， from 135.382 billion yuan to 197.077 billion yuan. Secondly， cultivated land resources in the Yangtze River Economic Belt were in a surplus state overall. The ecological value of cultivated land exhibited an “east-low and west-high” pattern. Sichuan had the highest ecological value and surplus quantity of cultivated land， while Shanghai had the lowest ecological value. Thirdly， from 2011 to 2021， the cultivated land ecological values of Zhejiang and Shanghai were deficit， Sichuan was in the ecological high-surplus area， Chongqing and Guizhou were in a balanced state， and Jiangxi， Anhui， and Jiangsu showed no significant changes in the ecological surplus or deficit of cultivated land. Yunnan and Hubei provinces saw an increase in the ecological surplus of cultivated land， while Hunan province experienced a decrease. Based on this， each province in the Yangtze River Economic Belt should make full use of its own resources and advantages， formulate and implement adaptive cultivated land protection strategies， so as to promote the sustainable use of cultivated land resources， and contribute to realize the goal of “ecological priority， green and low-carbon development” in the Yangtze River Economic Belt.
2024,43(3):65-74
, DOI: 10.13300/j.cnki.hnlkxb.2024.03.007
Abstract:
Developing eco-friendly and low-carbon agriculture is an effective pathway toward building a strong agricultural nation with Chinese characteristics and is also an important feature of modernizing agriculture in China. To promote the comprehensive green transformation of agricultural development and accelerate the construction of a strong agricultural country with Chinese characteristics，this article，based on clarifying the characteristics of ecological low-carbon agriculture，put forward the vision for developing ecological low-carbon agriculture. It analyzed the current realistic foundation and challenges of developing ecological low-carbon agriculture in China，and proposed strategic ideas accordingly. The study found that China has laid a certain foundation for the development of eco-friendly agriculture，but still faces challenges such as conflicting multiple goals，limited space for emission reduction and carbon sequestration，insufficient technological reserves，and difficulties in realizing the value of ecological products. In the new stage and new journey，the specific approach to develop eco-friendly and low-carbon agriculture involves fully utilizing farming experience and modern science and technology，simultaneously promoting green technological innovation and dissemination，and integrating proactive government policies with effective market mechanisms. The key tasks include improving the green-oriented agricultural subsidy system，establishing a technical system to support the development of eco-friendly and low-carbon agriculture，and establishing a sound mechanism to realize the value of ecological products.
Developing eco-friendly and low-carbon agriculture is an effective pathway toward building a strong agricultural nation with Chinese characteristics and is also an important feature of modernizing agriculture in China. To promote the comprehensive green transformation of agricultural development and accelerate the construction of a strong agricultural country with Chinese characteristics，this article，based on clarifying the characteristics of ecological low-carbon agriculture，put forward the vision for developing ecological low-carbon agriculture. It analyzed the current realistic foundation and challenges of developing ecological low-carbon agriculture in China，and proposed strategic ideas accordingly. The study found that China has laid a certain foundation for the development of eco-friendly agriculture，but still faces challenges such as conflicting multiple goals，limited space for emission reduction and carbon sequestration，insufficient technological reserves，and difficulties in realizing the value of ecological products. In the new stage and new journey，the specific approach to develop eco-friendly and low-carbon agriculture involves fully utilizing farming experience and modern science and technology，simultaneously promoting green technological innovation and dissemination，and integrating proactive government policies with effective market mechanisms. The key tasks include improving the green-oriented agricultural subsidy system，establishing a technical system to support the development of eco-friendly and low-carbon agriculture，and establishing a sound mechanism to realize the value of ecological products.
2024,43(3):75-88
, DOI: 10.13300/j.cnki.hnlkxb.2024.03.008
Abstract:
Reducing agricultural carbon emissions and improving the capacity of agricultural carbon sinks are important measures for China to realize the goal of “Dual-carbon”， which is also where the potential lies. Therefore， it is undoubtedly of great significance to clarify the current status of research on agricultural carbon issues and its characteristics. In order to contribute to the early realization of China’s “Dual-carbon” goal， this paper comprehensively comprehends the existing studies based on the three dimensions of agricultural carbon emissions， agricultural carbon sinks， and driving factors of agricultural low-carbon development. Specifically， firstly， the basic concepts of agricultural carbon emissions are clarified and common measurement methods are introduced， and the current research status is reviewed， taking into consideration temporal evolution， spatial distribution， efficiency characteristics， and emission reduction pathways. Secondly， the basic concepts of agricultural carbon sinks are defined， and the forest carbon sink， soil carbon sink and ocean carbon sink are derived， followed by the introduction of their respective measurement method. Then， the focus is on the net agricultural carbon sink and the marketization of carbon sink. Finally， the main factors that affect the development of low-carbon agriculture are discussed from both macro and micro levels. At the macro level， policy， economic and social factors are considered， while at the micro level， the internal factors of the head of the household and the external environment faced by the farmers are examined. With regards to the direction of future research on agricultural carbon issues， this paper believes that it should focus on the following four aspects， namely， the scientific prediction of agricultural carbon peaks and the design of differentiated emission reduction paths， the scientific assessment of the potential for agricultural carbon reduction and carbon sequestration and the discussion of paths to achieve these goals， the construction of an agricultural carbon market， and exploration of the idea of realizing the value of carbon sinks， as well as the exploration of the matching of the supply and demand of low-carbon production techniques by farmers and the optimization of their systems.
Reducing agricultural carbon emissions and improving the capacity of agricultural carbon sinks are important measures for China to realize the goal of “Dual-carbon”， which is also where the potential lies. Therefore， it is undoubtedly of great significance to clarify the current status of research on agricultural carbon issues and its characteristics. In order to contribute to the early realization of China’s “Dual-carbon” goal， this paper comprehensively comprehends the existing studies based on the three dimensions of agricultural carbon emissions， agricultural carbon sinks， and driving factors of agricultural low-carbon development. Specifically， firstly， the basic concepts of agricultural carbon emissions are clarified and common measurement methods are introduced， and the current research status is reviewed， taking into consideration temporal evolution， spatial distribution， efficiency characteristics， and emission reduction pathways. Secondly， the basic concepts of agricultural carbon sinks are defined， and the forest carbon sink， soil carbon sink and ocean carbon sink are derived， followed by the introduction of their respective measurement method. Then， the focus is on the net agricultural carbon sink and the marketization of carbon sink. Finally， the main factors that affect the development of low-carbon agriculture are discussed from both macro and micro levels. At the macro level， policy， economic and social factors are considered， while at the micro level， the internal factors of the head of the household and the external environment faced by the farmers are examined. With regards to the direction of future research on agricultural carbon issues， this paper believes that it should focus on the following four aspects， namely， the scientific prediction of agricultural carbon peaks and the design of differentiated emission reduction paths， the scientific assessment of the potential for agricultural carbon reduction and carbon sequestration and the discussion of paths to achieve these goals， the construction of an agricultural carbon market， and exploration of the idea of realizing the value of carbon sinks， as well as the exploration of the matching of the supply and demand of low-carbon production techniques by farmers and the optimization of their systems.
2024,43(3):89-99
, DOI: 10.13300/j.cnki.hnlkxb.2024.03.009
Abstract:
Ecological space is an important vehicle for maintaining regional carbon balance and securing carbon storage， and the redline area of ecological protection is an important part of ecological space. This article aimed at studying the spatial and temporal response of the carbon storage of the ecological space under the constraints of the ecological bottom line. The ArcGIS platform was used to integrate the PLUS model and the InVEST-Carbon model to predict and simulate the changes in carbon storage of ecological space and its spatial characteristics in Xiangyang City， Hubei Province， China， from 2000 to 2030. The results showed that the area of ecological space in Xiangyang City decreased between 2000 and 2020. It is predicted that the degradation rate of ecological space will decrease by 2030 under the constraints of the ecological bottom line. By 2030， the carbon storage in Xiangyang City will undergo a corresponding transformation due to changes in ecological space. The maximum carbon storage per grid unit is about 18.47 kg， mainly distributed in the forest land in the west， northeast， and southeast. The hotspot analysis presents a pattern of “concentrated hotspot and scattered cold spots”. The constraint of ecological bottom line helps to optimize the pattern of carbon hotspot in the ecological space of Xiangyang City. It will provide scientific guidance for implementing “carbon peaking and carbon neutrality” strategies and promoting low-carbon planning in similar regions.
Ecological space is an important vehicle for maintaining regional carbon balance and securing carbon storage， and the redline area of ecological protection is an important part of ecological space. This article aimed at studying the spatial and temporal response of the carbon storage of the ecological space under the constraints of the ecological bottom line. The ArcGIS platform was used to integrate the PLUS model and the InVEST-Carbon model to predict and simulate the changes in carbon storage of ecological space and its spatial characteristics in Xiangyang City， Hubei Province， China， from 2000 to 2030. The results showed that the area of ecological space in Xiangyang City decreased between 2000 and 2020. It is predicted that the degradation rate of ecological space will decrease by 2030 under the constraints of the ecological bottom line. By 2030， the carbon storage in Xiangyang City will undergo a corresponding transformation due to changes in ecological space. The maximum carbon storage per grid unit is about 18.47 kg， mainly distributed in the forest land in the west， northeast， and southeast. The hotspot analysis presents a pattern of “concentrated hotspot and scattered cold spots”. The constraint of ecological bottom line helps to optimize the pattern of carbon hotspot in the ecological space of Xiangyang City. It will provide scientific guidance for implementing “carbon peaking and carbon neutrality” strategies and promoting low-carbon planning in similar regions.
2024,43(3):100-110
, DOI: 10.13300/j.cnki.hnlkxb.2024.03.010
Abstract:
It is of great theoretical significance to study the changing characteristics of net carbon emissions and the capacity of regional carbon neutrality for accelerating the transformation of social and economic development and realizing the goal of carbon neutrality. In this article， the carbon emissions， carbon sinks and net carbon emissions in Hubei Province were evaluated with the methods given in IPCC Guidelines for National Greenhouse Gas Inventories and Guidelines for the Preparation of Provincial Greenhouse Gas Inventories， carbon density method and other methods. The changing trend of net carbon emissions was studied to evaluate the capacity of regional carbon neutrality in Hubei Province. The results showed that the total amount of regional carbon sinks in Hubei Province from 2000 to 2020 was 264.178 million tons， showing a significant upward trend over the years， with an increase rate of about 135.21% and an average annual increase rate of about 6.76%. The total carbon emissions in Hubei Province from 2000 to 2020 was 910.331 million tons. The changing trend of total carbon emissions over the years was divided into two stages including the total carbon emissions in Hubei Province from 2000 to 2010 and from 2011 to 2020 showing a trend of significant increase and a trend of fluctuating downward， respectively. The net carbon emissions in Hubei Province from 2000 to 2010 had an upward trend， and the ZM-K statistic passed the significance test with statistical significance. The net carbon emissions in Hubei Province from 2011 to 2020 had a downward trend， but the ZM-K statistic failed the significance test， indicating that the net carbon emissions in Hubei Province had a downward trend in the second stage， but this trend was not statistically significant. It is indicated that there is still a huge gap between the carbon sink and carbon emissions of the ecosystem in Hubei Province， and there is still some uncertainty in the changes of net carbon emissions. Carbon reduction should be continued. The carbon sink function of the ecosystem should be optimized， and carbon capture technology and related industries vigorously developed.
It is of great theoretical significance to study the changing characteristics of net carbon emissions and the capacity of regional carbon neutrality for accelerating the transformation of social and economic development and realizing the goal of carbon neutrality. In this article， the carbon emissions， carbon sinks and net carbon emissions in Hubei Province were evaluated with the methods given in IPCC Guidelines for National Greenhouse Gas Inventories and Guidelines for the Preparation of Provincial Greenhouse Gas Inventories， carbon density method and other methods. The changing trend of net carbon emissions was studied to evaluate the capacity of regional carbon neutrality in Hubei Province. The results showed that the total amount of regional carbon sinks in Hubei Province from 2000 to 2020 was 264.178 million tons， showing a significant upward trend over the years， with an increase rate of about 135.21% and an average annual increase rate of about 6.76%. The total carbon emissions in Hubei Province from 2000 to 2020 was 910.331 million tons. The changing trend of total carbon emissions over the years was divided into two stages including the total carbon emissions in Hubei Province from 2000 to 2010 and from 2011 to 2020 showing a trend of significant increase and a trend of fluctuating downward， respectively. The net carbon emissions in Hubei Province from 2000 to 2010 had an upward trend， and the ZM-K statistic passed the significance test with statistical significance. The net carbon emissions in Hubei Province from 2011 to 2020 had a downward trend， but the ZM-K statistic failed the significance test， indicating that the net carbon emissions in Hubei Province had a downward trend in the second stage， but this trend was not statistically significant. It is indicated that there is still a huge gap between the carbon sink and carbon emissions of the ecosystem in Hubei Province， and there is still some uncertainty in the changes of net carbon emissions. Carbon reduction should be continued. The carbon sink function of the ecosystem should be optimized， and carbon capture technology and related industries vigorously developed.
2024,43(3):111-120
, DOI: 10.13300/j.cnki.hnlkxb.2024.03.011
Abstract:
Banghu Lake， Changhu Lake， and Sizhoutou wetland on the Poyang Lake National Nature Reserve in Jiangxi Province were used to study the spatial distribution characteristics of the content of organic carbon in surface soil in seasonal flooded wetlands of Poyang Lake and the applicability of remote sensing methods for estimating the content of organic carbon in surface soil. Remote sensing image processing and GIS technology were used to extract feature factors of remote sensing from the images based on the data about the content of organic carbon in soil measured in the field and Landsat8 OLT remote sensing images from the same period. The regression models of univariate linear， univariate curve， and multiple stepwise linear for parameters of remote sensing and the content of organic carbon in soil were constructed. The optimal estimation models of remote sensing were selected by comparing and analyzing to predict the content of organic carbon in the surface layer （0-20 cm） of seasonal flooded wetlands in Poyang Lake. The results showed that 33 feature factors of remote sensing including reflectance values （b1-b7） in 7 bands， 4 vegetation indices（NDVI，SR，SAVI，EVI）， first principal component feature （PCA1）， the mean （MEAN） ， entropy （ENT）， and correlation （COR） of single band texture features were extracted from the images. Texture features were important factors of remote sensing for predicting the content of organic carbon in the areas studied， and their fitting effect with the multiple stepwise linear regression model Y=42.708－2.817Xb3MEAN－4.887Xb5COR＋0.667Xb7MEAN （b3MEAN，b5COR and b7MEAN representing the mean value， correlation and mean value of texture features in bands 3，5 and 7， respectively） constructed for the content of organic carbon in soil was the best. The determination coefficient of model， R2 was 0.772， with an average relative error （MRE） of 45.53% and a root mean square error （RMSE） of 2.417. The results of remote sensing inversion showed that the predicted content of organic carbon in surface soil in the areas studied was mainly concentrated at 0-20 g/kg， with an average content of organic carbon in soil about 10.75 g/kg. It is indicated that it is feasible to use remote sensing to predict the content of organic carbon in soil of wetlands.
Banghu Lake， Changhu Lake， and Sizhoutou wetland on the Poyang Lake National Nature Reserve in Jiangxi Province were used to study the spatial distribution characteristics of the content of organic carbon in surface soil in seasonal flooded wetlands of Poyang Lake and the applicability of remote sensing methods for estimating the content of organic carbon in surface soil. Remote sensing image processing and GIS technology were used to extract feature factors of remote sensing from the images based on the data about the content of organic carbon in soil measured in the field and Landsat8 OLT remote sensing images from the same period. The regression models of univariate linear， univariate curve， and multiple stepwise linear for parameters of remote sensing and the content of organic carbon in soil were constructed. The optimal estimation models of remote sensing were selected by comparing and analyzing to predict the content of organic carbon in the surface layer （0-20 cm） of seasonal flooded wetlands in Poyang Lake. The results showed that 33 feature factors of remote sensing including reflectance values （b1-b7） in 7 bands， 4 vegetation indices（NDVI，SR，SAVI，EVI）， first principal component feature （PCA1）， the mean （MEAN） ， entropy （ENT）， and correlation （COR） of single band texture features were extracted from the images. Texture features were important factors of remote sensing for predicting the content of organic carbon in the areas studied， and their fitting effect with the multiple stepwise linear regression model Y=42.708－2.817Xb3MEAN－4.887Xb5COR＋0.667Xb7MEAN （b3MEAN，b5COR and b7MEAN representing the mean value， correlation and mean value of texture features in bands 3，5 and 7， respectively） constructed for the content of organic carbon in soil was the best. The determination coefficient of model， R2 was 0.772， with an average relative error （MRE） of 45.53% and a root mean square error （RMSE） of 2.417. The results of remote sensing inversion showed that the predicted content of organic carbon in surface soil in the areas studied was mainly concentrated at 0-20 g/kg， with an average content of organic carbon in soil about 10.75 g/kg. It is indicated that it is feasible to use remote sensing to predict the content of organic carbon in soil of wetlands.
WENG Xuelian, JIANG Liqiu, TANG Shupeng, ZHANG Weiyang, ZHU Kuanyu, WANG Zhiqin, YANG Jianchang, XU Yunji
2024,43(3):121-131
, DOI: 10.13300/j.cnki.hnlkxb.2024.03.012
Abstract:
The taste quality of steaming and cooking is an important evaluation criterion for consumers when choosing rice.Starch，protein，and lipids，as the three main components of rice，are closely related to the taste quality of steaming and cooking in rice.This article reviewed the progress on the composition and distribution，anabolic characteristics of the three main components in rice and their relationship with the taste quality of steaming and cooking to further study the formation mechanism of the taste quality of steaming and cooking in rice and the techniques for cultivating the rice with high quality.The effects of irrigation with alternating wet and dry （AWD） on the three main components of rice and the taste quality of steaming and cooking in rice were summarized.Problems including the unclear relationship between the interaction of the three main components of rice and the taste quality of steaming and cooking in rice and the unknown mechanisms underlying the effects of AWD on the taste quality of steaming and cooking in rice were pointed out.It is recommended to conduct in-depth studies on the formation mechanism of the taste quality of steaming and cooking in rice and the regulatory mechanism of AWD on the taste quality of steaming and cooking in rice based on the relationship between the accumulation of starch，protein，and lipids and the anabolism of starch，protein，and lipids in the future.
The taste quality of steaming and cooking is an important evaluation criterion for consumers when choosing rice.Starch，protein，and lipids，as the three main components of rice，are closely related to the taste quality of steaming and cooking in rice.This article reviewed the progress on the composition and distribution，anabolic characteristics of the three main components in rice and their relationship with the taste quality of steaming and cooking to further study the formation mechanism of the taste quality of steaming and cooking in rice and the techniques for cultivating the rice with high quality.The effects of irrigation with alternating wet and dry （AWD） on the three main components of rice and the taste quality of steaming and cooking in rice were summarized.Problems including the unclear relationship between the interaction of the three main components of rice and the taste quality of steaming and cooking in rice and the unknown mechanisms underlying the effects of AWD on the taste quality of steaming and cooking in rice were pointed out.It is recommended to conduct in-depth studies on the formation mechanism of the taste quality of steaming and cooking in rice and the regulatory mechanism of AWD on the taste quality of steaming and cooking in rice based on the relationship between the accumulation of starch，protein，and lipids and the anabolism of starch，protein，and lipids in the future.
2024,43(3):132-138
, DOI: 10.13300/j.cnki.hnlkxb.2024.03.013
Abstract:
Field experiments were conducted on the cultivation of ratoon rice using the widely used Yongyou indica-japonica hybrid rice varieties Yongyou 1540 and Yongyou 4949 as experimental materials and the indica-hybrid rice variety Longliangyou 534 as control materials to study the ratoon characteristics and yield formation of Yongyou indica-japonica hybrid rice planted as ratoon rice. The results showed that there are significant differences in the ratoon characteristics between indica-japonica hybrid rice and indica- hybrid rice. The dominant regenerated nodes of the indica-japonica hybrid rice Yongyou 1540 and Yongyou 4949 were the 4th and 5th nodes from top at the lower nodes， which produced a sum of 81.9% and 68.9% of effective panicles with 89.6% and 72.5% of the yield contribution in YongYou 1540 and YongYou 4949， respectively. The panicle length and the number of grains per panicle of these two nodes were significantly higher than that of the 2nd and 3rd nodes from top， showing a decreasing trend from the bottom to the top. The 2nd and 3rd nodes from top at the higher nodes of the Longliangyou 534 were dominant， producing 71.5% of effective panicles with 72.5% of the yield contribution. The spike rate， ratios of effective panicle and yield contribution of were 89.4%， 74.6% and 79.2% for regenerated seedlings of YongYou 4949 within 1-7 d after the first harvesting， significantly higher than those of regenerated seedlings within 8-12 d and 12 d above after the first harvesting. The panicle length and the number of grains per panicle in regenerated seedlings of Yongyou 1540 and Yongyou 4949 were significantly higher than those of Longliangyou 534， with yield increase of 21.6% and 17.3%， respectively. It is indicated that the strong regeneration ability of the low nodes， long panicles， and large number of grains per panicle in regenerated seedlings of Yongyou indica-japonica hybrid rice are the key factors that make it easy to achieve high yield when planted as ratoon rice.
Field experiments were conducted on the cultivation of ratoon rice using the widely used Yongyou indica-japonica hybrid rice varieties Yongyou 1540 and Yongyou 4949 as experimental materials and the indica-hybrid rice variety Longliangyou 534 as control materials to study the ratoon characteristics and yield formation of Yongyou indica-japonica hybrid rice planted as ratoon rice. The results showed that there are significant differences in the ratoon characteristics between indica-japonica hybrid rice and indica- hybrid rice. The dominant regenerated nodes of the indica-japonica hybrid rice Yongyou 1540 and Yongyou 4949 were the 4th and 5th nodes from top at the lower nodes， which produced a sum of 81.9% and 68.9% of effective panicles with 89.6% and 72.5% of the yield contribution in YongYou 1540 and YongYou 4949， respectively. The panicle length and the number of grains per panicle of these two nodes were significantly higher than that of the 2nd and 3rd nodes from top， showing a decreasing trend from the bottom to the top. The 2nd and 3rd nodes from top at the higher nodes of the Longliangyou 534 were dominant， producing 71.5% of effective panicles with 72.5% of the yield contribution. The spike rate， ratios of effective panicle and yield contribution of were 89.4%， 74.6% and 79.2% for regenerated seedlings of YongYou 4949 within 1-7 d after the first harvesting， significantly higher than those of regenerated seedlings within 8-12 d and 12 d above after the first harvesting. The panicle length and the number of grains per panicle in regenerated seedlings of Yongyou 1540 and Yongyou 4949 were significantly higher than those of Longliangyou 534， with yield increase of 21.6% and 17.3%， respectively. It is indicated that the strong regeneration ability of the low nodes， long panicles， and large number of grains per panicle in regenerated seedlings of Yongyou indica-japonica hybrid rice are the key factors that make it easy to achieve high yield when planted as ratoon rice.
2024,43(3):139-147
, DOI: 10.13300/j.cnki.hnlkxb.2024.03.014
Abstract:
The ZmEREB46 （Zm00001d015759） gene as a member of the ERF family in maize was cloned to identify and mine the resistance genes to waterlogging stress in maize.The resequencing，functional mutation site and expression pattern of the ZmEREB46 gene were analyzed.The role of the ZmEREB46 gene in waterlogging tolerance in Arabidopsis thaliana was preliminarily studied.The results showed that ZmEREB46 encoded one AP2/EREBP transcription factor.There was a G/A conversion and a 911 bp fragment insertion in the coding and promoter regions of the ZmEREB46 gene in the waterlogging susceptible inbred line A3239，compared to the waterlogging tolerant inbred line A3237.The insertion of a 911 bp fragment in the waterlogging susceptible inbred line A3239 significantly inhibited the expression of ZmEREB46.The results of subcellular localization showed that ZmEREB46 was localized in the nucleus.The results of quantitative PCR （qRT-PCR） analysis showed that ZmEREB46 was up-regulated by waterlogging stress，and the expression level of ZmEREB46 in A3237 was two-fold higher than that in A3239 after 8 h of waterlogging treatment.The overexpression of ZmEREB46 in A. thaliana improved the waterlogging tolerance of A. thaliana at the stage of seedling.
The ZmEREB46 （Zm00001d015759） gene as a member of the ERF family in maize was cloned to identify and mine the resistance genes to waterlogging stress in maize.The resequencing，functional mutation site and expression pattern of the ZmEREB46 gene were analyzed.The role of the ZmEREB46 gene in waterlogging tolerance in Arabidopsis thaliana was preliminarily studied.The results showed that ZmEREB46 encoded one AP2/EREBP transcription factor.There was a G/A conversion and a 911 bp fragment insertion in the coding and promoter regions of the ZmEREB46 gene in the waterlogging susceptible inbred line A3239，compared to the waterlogging tolerant inbred line A3237.The insertion of a 911 bp fragment in the waterlogging susceptible inbred line A3239 significantly inhibited the expression of ZmEREB46.The results of subcellular localization showed that ZmEREB46 was localized in the nucleus.The results of quantitative PCR （qRT-PCR） analysis showed that ZmEREB46 was up-regulated by waterlogging stress，and the expression level of ZmEREB46 in A3237 was two-fold higher than that in A3239 after 8 h of waterlogging treatment.The overexpression of ZmEREB46 in A. thaliana improved the waterlogging tolerance of A. thaliana at the stage of seedling.
2024,43(3):148-157
, DOI: 10.13300/j.cnki.hnlkxb.2024.03.015
Abstract:
SSR markers were used to analyze the genetic diversity and construct a DNA molecular ID database of 60 buckwheat germplasms in order to accurately identify the buckwheat germplasm resources in Guizhou province. The results showed that 16 pairs of stable and polymorphic primers were screened from 100 pairs of SSR primers. A total of 174 polymorphic bands were amplified from 60 germplasm studied. The mean value of Shannon’s information index， Nei’s diversity index， and polymorphic information index was 0.337， 0.206， and 0.693， respectively. It is indicated that the polymorphism of primers is good， which can effectively identify the genetic diversity of 60 buckwheat germplasms. When the Dice genetic similarity coefficient was 0.374， all materials tested were clustered into three groups including A， B， and C. When the Dice genetic similarity coefficient was 0.484， the Tartary buckwheat group （Group A） was further divided into two subgroups including A1 and A2. The results of clustering SSR amplification products validated by capillary electrophoresis and 8 polyacrylamide gel （PAGE） electrophoresis were consistent. It is indicated that the efficient SSR molecular markers developed can effectively identify the genetic diversity and can be used to construct DNA molecular ID cards of important buckwheat germplasm in Guizhou province.
SSR markers were used to analyze the genetic diversity and construct a DNA molecular ID database of 60 buckwheat germplasms in order to accurately identify the buckwheat germplasm resources in Guizhou province. The results showed that 16 pairs of stable and polymorphic primers were screened from 100 pairs of SSR primers. A total of 174 polymorphic bands were amplified from 60 germplasm studied. The mean value of Shannon’s information index， Nei’s diversity index， and polymorphic information index was 0.337， 0.206， and 0.693， respectively. It is indicated that the polymorphism of primers is good， which can effectively identify the genetic diversity of 60 buckwheat germplasms. When the Dice genetic similarity coefficient was 0.374， all materials tested were clustered into three groups including A， B， and C. When the Dice genetic similarity coefficient was 0.484， the Tartary buckwheat group （Group A） was further divided into two subgroups including A1 and A2. The results of clustering SSR amplification products validated by capillary electrophoresis and 8 polyacrylamide gel （PAGE） electrophoresis were consistent. It is indicated that the efficient SSR molecular markers developed can effectively identify the genetic diversity and can be used to construct DNA molecular ID cards of important buckwheat germplasm in Guizhou province.
2024,43(3):158-166
, DOI: 10.13300/j.cnki.hnlkxb.2024.03.016
Abstract:
A highly glyphosate resistant strain of Halomonas sp. was screened from marine bacteria to breed crops with high glyphosate resistance to cope with the evolution of glyphosate weeds. The gene encoding EPSPS in this strain was identified through sequencing genome and bioinformatics analysis. The fHoEPSPS， mfHoEPSPS （G384A site mutant）， and mHoEPSPS （a mutant with N-end PDT deletion of mfHoEPSPS） were recombinantly expressed and purified in E. coli （DE3）. A gene pyramiding strategy mediated by the self-cleaving peptide LP4/2A was used to locate the glufosinate-resistant enzyme （Repat） at the N-end of mHoEPSPS. A dual resistance to glyphosate/ammonium phosphatase （RLH） was constructed. Tobacco transformed with the RLH gene exhibited simultaneous resistance to glyphosate/glufosinate compound herbicides. The results showed that the EPSPS gene （fHoEPSPS） of this strain encoded an N-end fused with a bifunctional enzyme of prephenate dehydratase （PDT）. The results of analyzing glyphosate resistance showed that the resistance of mfHoEPSPS was 19 times higher than that of fHoEPSPS. Introducing the coding gene of mHoEPSPS into tobacco endowed tobacco with three times the recommended dose of glyphosate tolerance. Tobacco plants transformed with the RLH gene had simultaneous tolerance 3-5 times the recommended dosage of glyphosate/ammonium phosphine compound herbicides. It is indicated that the glyphosate-resistant EPSPS derived from Halomonas sp. is a new type of glyphosate-tolerant enzyme. The enzyme activity is further improved through the G384A site mutation. The transgenic tobacco with RLH gene obtained through gene pyramiding strategy mediated by the self-cleaving peptides shows high glyphosate/glufosinate compound resistance. It will provide ideas for dealing with the evolution of glyphosate weeds.
A highly glyphosate resistant strain of Halomonas sp. was screened from marine bacteria to breed crops with high glyphosate resistance to cope with the evolution of glyphosate weeds. The gene encoding EPSPS in this strain was identified through sequencing genome and bioinformatics analysis. The fHoEPSPS， mfHoEPSPS （G384A site mutant）， and mHoEPSPS （a mutant with N-end PDT deletion of mfHoEPSPS） were recombinantly expressed and purified in E. coli （DE3）. A gene pyramiding strategy mediated by the self-cleaving peptide LP4/2A was used to locate the glufosinate-resistant enzyme （Repat） at the N-end of mHoEPSPS. A dual resistance to glyphosate/ammonium phosphatase （RLH） was constructed. Tobacco transformed with the RLH gene exhibited simultaneous resistance to glyphosate/glufosinate compound herbicides. The results showed that the EPSPS gene （fHoEPSPS） of this strain encoded an N-end fused with a bifunctional enzyme of prephenate dehydratase （PDT）. The results of analyzing glyphosate resistance showed that the resistance of mfHoEPSPS was 19 times higher than that of fHoEPSPS. Introducing the coding gene of mHoEPSPS into tobacco endowed tobacco with three times the recommended dose of glyphosate tolerance. Tobacco plants transformed with the RLH gene had simultaneous tolerance 3-5 times the recommended dosage of glyphosate/ammonium phosphine compound herbicides. It is indicated that the glyphosate-resistant EPSPS derived from Halomonas sp. is a new type of glyphosate-tolerant enzyme. The enzyme activity is further improved through the G384A site mutation. The transgenic tobacco with RLH gene obtained through gene pyramiding strategy mediated by the self-cleaving peptides shows high glyphosate/glufosinate compound resistance. It will provide ideas for dealing with the evolution of glyphosate weeds.
2024,43(3):167-175
, DOI: 10.13300/j.cnki.hnlkxb.2024.03.017
Abstract:
“Yunxue 1” variety and the multivariate statistical analysis was used to study the climate resource allocation basis of tobacco leaves for cigar wrapper and its impact on the agronomic traits of tobacco plants and the chemical composition of fermented tobacco leaves by changing the climate indicators during the growth period of tobacco plants through adjusting the period of transplanting to study the basis of climate resource allocation for the production of tobacco leaves for cigar wrapper.The results of correlation analysis showed that the accumulated temperature， effective accumulated temperature ≥10 ℃， total precipitation， and total temperature difference during the field stage of tobacco plants had a significant impact on every indicator of agronomic traits， with correlation coefficient ranging from 0.478 to 0.939.The accumulated temperature， effective accumulated temperature ≥10 ℃， and average temperature had a significant impact on the content of total sugar， nicotine， total nitrogen， and protein in tobacco leaves， with correlation coefficient ranging from -0.955 to -1.000.Two principal factors including climate accumulation factor and humidity factor were extracted from eight climate indicators with factor analysis.The results of grey correlation analysis showed that the two factors mentioned above were the main factors affecting the agronomic traits of tobacco plants and the conventional chemical components of tobacco leaves.It is indicated that the main climatic factors for determining the transplanting period of tobacco plants for cigar wrapper are based on the comprehensive configuration of temperature， precipitation， and relative humidity during the period of field growth.
“Yunxue 1” variety and the multivariate statistical analysis was used to study the climate resource allocation basis of tobacco leaves for cigar wrapper and its impact on the agronomic traits of tobacco plants and the chemical composition of fermented tobacco leaves by changing the climate indicators during the growth period of tobacco plants through adjusting the period of transplanting to study the basis of climate resource allocation for the production of tobacco leaves for cigar wrapper.The results of correlation analysis showed that the accumulated temperature， effective accumulated temperature ≥10 ℃， total precipitation， and total temperature difference during the field stage of tobacco plants had a significant impact on every indicator of agronomic traits， with correlation coefficient ranging from 0.478 to 0.939.The accumulated temperature， effective accumulated temperature ≥10 ℃， and average temperature had a significant impact on the content of total sugar， nicotine， total nitrogen， and protein in tobacco leaves， with correlation coefficient ranging from -0.955 to -1.000.Two principal factors including climate accumulation factor and humidity factor were extracted from eight climate indicators with factor analysis.The results of grey correlation analysis showed that the two factors mentioned above were the main factors affecting the agronomic traits of tobacco plants and the conventional chemical components of tobacco leaves.It is indicated that the main climatic factors for determining the transplanting period of tobacco plants for cigar wrapper are based on the comprehensive configuration of temperature， precipitation， and relative humidity during the period of field growth.
2024,43(3):176-184
, DOI: 10.13300/j.cnki.hnlkxb.2024.03.018
Abstract:
Cadmium pollution in soil brings a serious threat to food security and human health， and the problem of cadmium pollution in paddy fields is a priority for heavy metal pollution and prevention in soil.Pot experiments were conducted to screen suitable cadmium passivators for soil remediation in farmland.10 passivators including T1 （anomaterials， etc.）， T2 （lime）， T3 （oyster shells， etc.）， T4 （CaO）， T5 （silica-calcium fertilizers）， T6 （organic fertilizers of goat dung）， T7 （Bacillus cereus， etc.）， T8 （organic fertilizers of pig manure）， T9 （oyster shells）， and T10 （microorganisms， etc.） were used to compare the remediation effect of 10 passivators on cadmium contaminated rice paddy and the growth of rice.The results showed that passivators increased the pH of soil in rice paddy and altered the form of cadmium stored in the soil.The content of exchangeable cadmium in the soil treated with each passivator decreased by 4.6% to 44.8% compared to the control， with significant decrease in T8 （44.8%）， T6 （36%）， T1 （31.15%）， and T10 （28.4%）.The content of carbonate bound states increased.The changes in the content of Fe-Mn oxide-bound state and organic matter bound state were not significant.The proportion of residual cadmium showed an overall upward trend， with T6 having the largest increase， increasing by 53.85% compared to that of the control.The biomass of rice seeds treated with various passivators increased by 5.75% to 25.30%.The content of cadmium in the seeds， husks， and straw of rice was in the decreasing order of straw > grain > husk.The content of cadmium in the rice seeds ranged from 0.068 to 0.254 mg/kg， with T2 （0.152 mg/kg）， T5 （0.143 mg/kg）， T6 （0.088 mg/kg）， T7 （0.126 mg/kg）， T8 （0.072 mg/kg）， T9 （0.068 mg/kg）， and T10 （0.071 mg/kg） being lower than the national limit standard （0.2 mg/kg）.The content of cadmium in rice seeds of T6，T8，T9， and T10 significantly decreased by 61.90%， 68.83%， 70.56%， and 69.26%， respectively， compared to that of the control.T2， T6， and T8 had better effects of passivation based on analyzing the transformation of cadmium form in soil， rice biomass， and the content of cadmium in rice seeds.
Cadmium pollution in soil brings a serious threat to food security and human health， and the problem of cadmium pollution in paddy fields is a priority for heavy metal pollution and prevention in soil.Pot experiments were conducted to screen suitable cadmium passivators for soil remediation in farmland.10 passivators including T1 （anomaterials， etc.）， T2 （lime）， T3 （oyster shells， etc.）， T4 （CaO）， T5 （silica-calcium fertilizers）， T6 （organic fertilizers of goat dung）， T7 （Bacillus cereus， etc.）， T8 （organic fertilizers of pig manure）， T9 （oyster shells）， and T10 （microorganisms， etc.） were used to compare the remediation effect of 10 passivators on cadmium contaminated rice paddy and the growth of rice.The results showed that passivators increased the pH of soil in rice paddy and altered the form of cadmium stored in the soil.The content of exchangeable cadmium in the soil treated with each passivator decreased by 4.6% to 44.8% compared to the control， with significant decrease in T8 （44.8%）， T6 （36%）， T1 （31.15%）， and T10 （28.4%）.The content of carbonate bound states increased.The changes in the content of Fe-Mn oxide-bound state and organic matter bound state were not significant.The proportion of residual cadmium showed an overall upward trend， with T6 having the largest increase， increasing by 53.85% compared to that of the control.The biomass of rice seeds treated with various passivators increased by 5.75% to 25.30%.The content of cadmium in the seeds， husks， and straw of rice was in the decreasing order of straw > grain > husk.The content of cadmium in the rice seeds ranged from 0.068 to 0.254 mg/kg， with T2 （0.152 mg/kg）， T5 （0.143 mg/kg）， T6 （0.088 mg/kg）， T7 （0.126 mg/kg）， T8 （0.072 mg/kg）， T9 （0.068 mg/kg）， and T10 （0.071 mg/kg） being lower than the national limit standard （0.2 mg/kg）.The content of cadmium in rice seeds of T6，T8，T9， and T10 significantly decreased by 61.90%， 68.83%， 70.56%， and 69.26%， respectively， compared to that of the control.T2， T6， and T8 had better effects of passivation based on analyzing the transformation of cadmium form in soil， rice biomass， and the content of cadmium in rice seeds.
2024,43(3):185-193
, DOI: 10.13300/j.cnki.hnlkxb.2024.03.019
Abstract:
The purplish soil from the landfill in Yunxi Town， Yanting County， Sichuan Province was used to study the changes in the content of available heavy metals including Cd，Cu，Pb，Zn before and after passivation culture. Different mass ratios of silicon fertilizer （Si1：0.5%， Si2：1.0%） and phosphate ore powder （P1：0.2%， P2：0.4%， P3：1.0%） were mixed as compound and added to the soil. The passivation was cultured for 90 days. The effectiveness of soil remediation was evaluated with risk assessment code （RAC）. The results showed that the effectiveness of heavy metals under the treatment with high silicon （Si2：1.0%） was significantly reduced compared with that under the treatment with low silicon （Si1：0.5%）. Among them， Si2P3 treatment had the highest passivation rate for Cd， Cu， Pb， and Zn， which was 30.79%， 27.27%， 27.13%， and 36.88%， respectively. There was no significant difference between Si2P1 treatment and Si2P2 treatment. Si2P1 treatment significantly reduced the toxicity of heavy metal leaching and the RAC risk assessment code of heavy metals. It is indicated that the passivator for compound mainly enhanced the complex-precipitation of functional groups （O-Si-O，Si-O-Si，H2PO4-，PO43-， etc.） by increasing the pH and EC value in soil， promoting the transformation of heavy metals from highly active weak acid extraction and reducible states to low actively oxidizable and residual states. Overall， the application amount of Si2P1 passivator is lower， making it more suitable for the remediation of heavy metal contaminated soil in landfills.
The purplish soil from the landfill in Yunxi Town， Yanting County， Sichuan Province was used to study the changes in the content of available heavy metals including Cd，Cu，Pb，Zn before and after passivation culture. Different mass ratios of silicon fertilizer （Si1：0.5%， Si2：1.0%） and phosphate ore powder （P1：0.2%， P2：0.4%， P3：1.0%） were mixed as compound and added to the soil. The passivation was cultured for 90 days. The effectiveness of soil remediation was evaluated with risk assessment code （RAC）. The results showed that the effectiveness of heavy metals under the treatment with high silicon （Si2：1.0%） was significantly reduced compared with that under the treatment with low silicon （Si1：0.5%）. Among them， Si2P3 treatment had the highest passivation rate for Cd， Cu， Pb， and Zn， which was 30.79%， 27.27%， 27.13%， and 36.88%， respectively. There was no significant difference between Si2P1 treatment and Si2P2 treatment. Si2P1 treatment significantly reduced the toxicity of heavy metal leaching and the RAC risk assessment code of heavy metals. It is indicated that the passivator for compound mainly enhanced the complex-precipitation of functional groups （O-Si-O，Si-O-Si，H2PO4-，PO43-， etc.） by increasing the pH and EC value in soil， promoting the transformation of heavy metals from highly active weak acid extraction and reducible states to low actively oxidizable and residual states. Overall， the application amount of Si2P1 passivator is lower， making it more suitable for the remediation of heavy metal contaminated soil in landfills.
2024,43(3):194-202
, DOI: 10.13300/j.cnki.hnlkxb.2024.03.020
Abstract:
Field experiments were conducted in 11 major winter rapeseed producing counties （cities， districts） in Guizhou Province for two consecutive years from 2018 to 2019 and 2019 to 2020 to optimize the models of fertilizer and pesticide for winter rapeseed with direct seeding in Karst mountainous areas of Guizhou Province. The effects of different models of fertilizer and pesticide including the traditional model of fertilizer and pesticide （T1）， the optimized model of fertilizer and pesticide （T2）， no fertilizer application under the optimized model of fertilizer and pesticide （T3）， and no pesticide spraying under the optimized model of fertilizer and pesticide （T4） on the yield and economic benefits of winter rapeseed with direct seeding were studied. The techniques with high-yield and efficient fertilizer and pesticide suitable for winter rapeseed with direct seeding in Karst mountainous areas of Guizhou Province were explored. The results showed that the total nutrient input of T2 decreased by 19.9% and the pesticide input decreased by 69.5% compared with that of T1. The plant height， stem diameter， effective number of branches per shoot， pod length， pod density of winter rapeseed with direct seeding under T2 was lower than that under T1， with a decrease of 9.8%， 26.4%，10.9%， 10.2%， 24.2% from 2018 to 2019， and 9.5%， 28.3%， 12.8%， 10.9% and 23.9%， from 2019 to 2020. T2 had an advantage of population with a significant increase in harvest density of 199.0% and 194.2%in two consecutive years compared to T1. In two consecutive years， the yield of winter rapeseed under T2 was 2 224.4 kg/hm2 and 2 103.3 kg/hm2， increasing by 204.0 kg/hm2 and 74.3 kg/hm2 compared to that under T1. The utilization efficiency of fertilizer and control efficiency of pesticide under T2 was 2.20 kg/kg， 2.14 kg/kg and 141.82 kg/kg， 106.23 kg/kg， significantly higher than that under T1. The total output value and net benefit of winter rapeseed in two consecutive years under T2 was 11 121.8 yuan/hm2， 10 516.4 yuan/hm2 and 5 286.8 yuan/hm2， 4 681.4 yuan/hm2， an increase of 1 020.0 yuan/hm2， 371.6 yuan/hm2， 26 285.0 yuan/hm2 and 1 976.6 yuan/hm compared to that under T1， achieving cost savings and income increase. It is indicated that the optimized model of fertilizer and pesticide （T2） can meet the requirements for the growth of winter rapeseed with direct seeding in Karst mountainous areas of Guizhou Province， effectively improving the yield， the utilization efficiency of fertilizer and pesticide， and the economic benefits of winter rapeseed. This optimized model of fertilizer and pesticide （T2） can be promoted and applied as the main promotion model for the production of winter rapeseed with direct seeding in Karst mountainous areas of Guizhou Province.
Field experiments were conducted in 11 major winter rapeseed producing counties （cities， districts） in Guizhou Province for two consecutive years from 2018 to 2019 and 2019 to 2020 to optimize the models of fertilizer and pesticide for winter rapeseed with direct seeding in Karst mountainous areas of Guizhou Province. The effects of different models of fertilizer and pesticide including the traditional model of fertilizer and pesticide （T1）， the optimized model of fertilizer and pesticide （T2）， no fertilizer application under the optimized model of fertilizer and pesticide （T3）， and no pesticide spraying under the optimized model of fertilizer and pesticide （T4） on the yield and economic benefits of winter rapeseed with direct seeding were studied. The techniques with high-yield and efficient fertilizer and pesticide suitable for winter rapeseed with direct seeding in Karst mountainous areas of Guizhou Province were explored. The results showed that the total nutrient input of T2 decreased by 19.9% and the pesticide input decreased by 69.5% compared with that of T1. The plant height， stem diameter， effective number of branches per shoot， pod length， pod density of winter rapeseed with direct seeding under T2 was lower than that under T1， with a decrease of 9.8%， 26.4%，10.9%， 10.2%， 24.2% from 2018 to 2019， and 9.5%， 28.3%， 12.8%， 10.9% and 23.9%， from 2019 to 2020. T2 had an advantage of population with a significant increase in harvest density of 199.0% and 194.2%in two consecutive years compared to T1. In two consecutive years， the yield of winter rapeseed under T2 was 2 224.4 kg/hm2 and 2 103.3 kg/hm2， increasing by 204.0 kg/hm2 and 74.3 kg/hm2 compared to that under T1. The utilization efficiency of fertilizer and control efficiency of pesticide under T2 was 2.20 kg/kg， 2.14 kg/kg and 141.82 kg/kg， 106.23 kg/kg， significantly higher than that under T1. The total output value and net benefit of winter rapeseed in two consecutive years under T2 was 11 121.8 yuan/hm2， 10 516.4 yuan/hm2 and 5 286.8 yuan/hm2， 4 681.4 yuan/hm2， an increase of 1 020.0 yuan/hm2， 371.6 yuan/hm2， 26 285.0 yuan/hm2 and 1 976.6 yuan/hm compared to that under T1， achieving cost savings and income increase. It is indicated that the optimized model of fertilizer and pesticide （T2） can meet the requirements for the growth of winter rapeseed with direct seeding in Karst mountainous areas of Guizhou Province， effectively improving the yield， the utilization efficiency of fertilizer and pesticide， and the economic benefits of winter rapeseed. This optimized model of fertilizer and pesticide （T2） can be promoted and applied as the main promotion model for the production of winter rapeseed with direct seeding in Karst mountainous areas of Guizhou Province.
2024,43(3):203-213
, DOI: 10.13300/j.cnki.hnlkxb.2024.03.021
Abstract:
Two treatments including co-cropping Zizania latifolia with crayfish （ZC） and Zizania latifolia monoculture （Z） were set up to study the effects of co-cropping Zizania latifolia with crayfish on the content of nitrogen and phosphorus in soil， the accumulation of dry matter and the uptake and distribution of nitrogen， phosphorus， and potassium in Zizania latifolia to explore fertilization strategies for the planting and farming mode of Zizania latifolia. The results of two years showed that ZC increased the content of total nitrogen， total phosphorus， and available phosphorus in the soil during the harvesting period by 10.85% to 38.89%， 5.45% to 13.79%， and 6.19% to 61.79%， respectively， compared to Z. ZC increased the net Zizania latifolia yield by 5.10% to 19.54%. ZC increased the accumulation of dry matter in the stem， leaf， and net Zizania latifolia during the harvesting period by 14.41% to 16.58%， 10.28% to 15.15%， and 10.57% to 21.45%， respectively. In 2021， ZC significantly increased the content of nitrogen in leaves by 25.74% compared to Z during the harvesting period of Zizania latifolia， but significantly reduced the content of phosphorus in stems by 16.76% during the pregnancy period of Zizania latifolia. In 2022， ZC significantly reduced the content of nitrogen in stem by 23.75% during the pregnancy period of Zizania latifolia and the content of phosphorus in leaves by 12.08% during the tillering period of Zizania latifolia compared to Z under the reduction of nitrogen fertilizer and reduced feeding. There was no significant difference in the content of potassium in the same organ during the entire two-year growth period between the two treatments. For nutrient accumulation， the accumulation of nitrogen， phosphorus， and potassium in the leaves of Zizania latifolia under ZC in 2021 significantly decreased by 26.04%， 27.27%， and 30.11% compared to Z during the tillering period. However， the accumulation of nitrogen and potassium in the stems and leaves during the harvesting period under ZC significantly increased by 18.80%， 38.41%， 44.77%， and 35.71%， respectively， compared to Z. In 2022， the accumulation of phosphorus in the leaves and accumulation of potassium in the stems of ZC significantly increased by 30.0% and 30.77% compared to Z during the harvesting period under the reduction of nitrogen fertilizer and reduced feeding. For nutrient distribution， the distribution of nitrogen in the two treatments of Zizania latifolia during the pregnancy and harvesting period was mainly in the stem and leaves， while the distribution of phosphorus and potassium elements was mainly in the stem， with distribution ratio of 42% to 66% in stem. For nutrient transport， the roots， stems， and leaves of the two treatments of Zizania latifolia mostly exhibited “sink”organs in nitrogen and phosphorus transport in 2021， while they mostly exhibited “source” organs in potassium transport. In 2022， the roots， stems， and leaves of Zizania latifolia in the two treatments mostly represented “source” organs in nitrogen， phosphorus， and potassium transport under the reduction of nitrogen fertilizer and reduced feeding. It is indicated that reducing the input of fertilizer and feed appropriately in the co-cropping Zizania latifolia with crayfish can promote the formation of a reasonable source and sink relationship， which is conducive to the formation of yield.
Two treatments including co-cropping Zizania latifolia with crayfish （ZC） and Zizania latifolia monoculture （Z） were set up to study the effects of co-cropping Zizania latifolia with crayfish on the content of nitrogen and phosphorus in soil， the accumulation of dry matter and the uptake and distribution of nitrogen， phosphorus， and potassium in Zizania latifolia to explore fertilization strategies for the planting and farming mode of Zizania latifolia. The results of two years showed that ZC increased the content of total nitrogen， total phosphorus， and available phosphorus in the soil during the harvesting period by 10.85% to 38.89%， 5.45% to 13.79%， and 6.19% to 61.79%， respectively， compared to Z. ZC increased the net Zizania latifolia yield by 5.10% to 19.54%. ZC increased the accumulation of dry matter in the stem， leaf， and net Zizania latifolia during the harvesting period by 14.41% to 16.58%， 10.28% to 15.15%， and 10.57% to 21.45%， respectively. In 2021， ZC significantly increased the content of nitrogen in leaves by 25.74% compared to Z during the harvesting period of Zizania latifolia， but significantly reduced the content of phosphorus in stems by 16.76% during the pregnancy period of Zizania latifolia. In 2022， ZC significantly reduced the content of nitrogen in stem by 23.75% during the pregnancy period of Zizania latifolia and the content of phosphorus in leaves by 12.08% during the tillering period of Zizania latifolia compared to Z under the reduction of nitrogen fertilizer and reduced feeding. There was no significant difference in the content of potassium in the same organ during the entire two-year growth period between the two treatments. For nutrient accumulation， the accumulation of nitrogen， phosphorus， and potassium in the leaves of Zizania latifolia under ZC in 2021 significantly decreased by 26.04%， 27.27%， and 30.11% compared to Z during the tillering period. However， the accumulation of nitrogen and potassium in the stems and leaves during the harvesting period under ZC significantly increased by 18.80%， 38.41%， 44.77%， and 35.71%， respectively， compared to Z. In 2022， the accumulation of phosphorus in the leaves and accumulation of potassium in the stems of ZC significantly increased by 30.0% and 30.77% compared to Z during the harvesting period under the reduction of nitrogen fertilizer and reduced feeding. For nutrient distribution， the distribution of nitrogen in the two treatments of Zizania latifolia during the pregnancy and harvesting period was mainly in the stem and leaves， while the distribution of phosphorus and potassium elements was mainly in the stem， with distribution ratio of 42% to 66% in stem. For nutrient transport， the roots， stems， and leaves of the two treatments of Zizania latifolia mostly exhibited “sink”organs in nitrogen and phosphorus transport in 2021， while they mostly exhibited “source” organs in potassium transport. In 2022， the roots， stems， and leaves of Zizania latifolia in the two treatments mostly represented “source” organs in nitrogen， phosphorus， and potassium transport under the reduction of nitrogen fertilizer and reduced feeding. It is indicated that reducing the input of fertilizer and feed appropriately in the co-cropping Zizania latifolia with crayfish can promote the formation of a reasonable source and sink relationship， which is conducive to the formation of yield.
2024,43(3):214-219
, DOI: 10.13300/j.cnki.hnlkxb.2024.03.022
Abstract:
The nylon net cages self-made were used to study the characteristics of straw decomposition， nutrient release characteristics， and surface microstructure changes of rice under the disturbance from crayfish simulated in a trenche for aquaculture with rice-crayfish model and with no crayfish as a control in order to investigate the process and characteristics of straw decomposition of rice participated by crayfish under continuous soaking conditions， improve the technology for returning rice straw to the field in the rice-crayfish model， and realize the efficient utilization of straw resources and sustainable development of farmland. The results showed that the average decomposition rate of rice straw in each stage showed a characteristic of fast-slow-fast-slow-fast regardless of whether crayfish participated or not. There was no significant difference in the amount of decomposition， cumulative decomposition rate， and average decomposition rate between the treatment with crayfish and the treatment without crayfish before 150 days. All indexes of the treatment with crayfish were significantly higher than those of the treatment without crayfish after 180 days. The cumulative decomposition rate of rice straw in the treatment with crayfish reached 85.67%， which was 12.35 percentage points higher than that in the treatment without crayfish at 210 days. The cumulative release rate of straw nutrients was in the decreasing order of K>P>N. The cumulative release rate of N in the treatment with crayfish was higher than that in the treatment without crayfish after 150 days. The cumulative release rate of P and the cumulative release rate of total nutrient in the treatment with crayfish were higher trend than those in the treatment without crayfish after 180 days. The cumulative release rate of K in the treatment with crayfish was higher than that in the treatment without crayfish at 210 days. The surface structure of straw treated with crayfish was significantly more damaged than that treated without crayfish after 120 days. It is indicated that the disturbance from crayfish can increase the degree of damage to the surface microstructure of rice straw at the middle and late stages， promote the decomposition and nutrient release of rice straw at the late stage in a trenche for aquaculture with rice-crayfish model.
The nylon net cages self-made were used to study the characteristics of straw decomposition， nutrient release characteristics， and surface microstructure changes of rice under the disturbance from crayfish simulated in a trenche for aquaculture with rice-crayfish model and with no crayfish as a control in order to investigate the process and characteristics of straw decomposition of rice participated by crayfish under continuous soaking conditions， improve the technology for returning rice straw to the field in the rice-crayfish model， and realize the efficient utilization of straw resources and sustainable development of farmland. The results showed that the average decomposition rate of rice straw in each stage showed a characteristic of fast-slow-fast-slow-fast regardless of whether crayfish participated or not. There was no significant difference in the amount of decomposition， cumulative decomposition rate， and average decomposition rate between the treatment with crayfish and the treatment without crayfish before 150 days. All indexes of the treatment with crayfish were significantly higher than those of the treatment without crayfish after 180 days. The cumulative decomposition rate of rice straw in the treatment with crayfish reached 85.67%， which was 12.35 percentage points higher than that in the treatment without crayfish at 210 days. The cumulative release rate of straw nutrients was in the decreasing order of K>P>N. The cumulative release rate of N in the treatment with crayfish was higher than that in the treatment without crayfish after 150 days. The cumulative release rate of P and the cumulative release rate of total nutrient in the treatment with crayfish were higher trend than those in the treatment without crayfish after 180 days. The cumulative release rate of K in the treatment with crayfish was higher than that in the treatment without crayfish at 210 days. The surface structure of straw treated with crayfish was significantly more damaged than that treated without crayfish after 120 days. It is indicated that the disturbance from crayfish can increase the degree of damage to the surface microstructure of rice straw at the middle and late stages， promote the decomposition and nutrient release of rice straw at the late stage in a trenche for aquaculture with rice-crayfish model.
2024,43(3):220-229
, DOI: 10.13300/j.cnki.hnlkxb.2024.03.023
Abstract:
As an important part of urban public space， community public sports service space is the primary place for people to keep fit. Public sports space with high quality can effectively improve the life quality of people. At present， the public sports service space in China is still at the stage of "reconstruction， establishment and neglect of management". The lack of consideration on the use of venues and the satisfaction of residents in planning and construction has led to unscientific allocation of public sports service space， low efficiency of utilization and low level of service， which has affected the development of national fitness. In addition， the old public sports service space in the old city has been unable to effectively meet the high-quality fitness needs of people with the increasing number of residents in the old city and the aging of public sports service facilities. Therefore， it is particularly important to optimize the layout of new and reconstructed public sports service facilities. Jinniu District， Chengdu City was used to conduct empirical studies. POI （roint of interest） for data collection was collected. The accessibility of large public sports facilities was analyzed with ArcGIS road network analysis method. Gini coefficient and Lorenz curve were used to analyze the fairness of the spatial layout of public sports service. The results showed that there were some problems including insufficient scale of public sports service space， low accessibility from residential areas to public sports facilities， and mismatch between the distribution of population and the layout of public sports space in Jinniu District. It is proposed to increase the supply of public sports facilities， improve the transportation conditions from public sports facilities to residential areas， and improve the coverage of public sports space in populous streets to solve the difficulties in fitness and bad experience of fitness in old communities， and promote the development of national fitness with high-quality.
As an important part of urban public space， community public sports service space is the primary place for people to keep fit. Public sports space with high quality can effectively improve the life quality of people. At present， the public sports service space in China is still at the stage of "reconstruction， establishment and neglect of management". The lack of consideration on the use of venues and the satisfaction of residents in planning and construction has led to unscientific allocation of public sports service space， low efficiency of utilization and low level of service， which has affected the development of national fitness. In addition， the old public sports service space in the old city has been unable to effectively meet the high-quality fitness needs of people with the increasing number of residents in the old city and the aging of public sports service facilities. Therefore， it is particularly important to optimize the layout of new and reconstructed public sports service facilities. Jinniu District， Chengdu City was used to conduct empirical studies. POI （roint of interest） for data collection was collected. The accessibility of large public sports facilities was analyzed with ArcGIS road network analysis method. Gini coefficient and Lorenz curve were used to analyze the fairness of the spatial layout of public sports service. The results showed that there were some problems including insufficient scale of public sports service space， low accessibility from residential areas to public sports facilities， and mismatch between the distribution of population and the layout of public sports space in Jinniu District. It is proposed to increase the supply of public sports facilities， improve the transportation conditions from public sports facilities to residential areas， and improve the coverage of public sports space in populous streets to solve the difficulties in fitness and bad experience of fitness in old communities， and promote the development of national fitness with high-quality.
WU Qiuxia, YI Qixian, CHEN Xi, FAN Xibei, TANG Xinyan, WANG Jingyun, YIN Mingxuan, ZHENG Riru, CHEN Shenghong, YUAN Huihong
2024,43(3):230-239
, DOI: 10.13300/j.cnki.hnlkxb.2024.03.024
Abstract:
The headspace solid-phase microextraction combined with gas chromatography-mass spectrometry （HS-SPEM-GC-MS） technology was used to detect volatile substances in 30 common cultivated varieties of pantropical water lilies to detect the volatile components， identify the aroma active substances， and screen the excellent aromatic varieties of water lilies. The results showed that a total of 60 volatile compounds were identified in the 30 varieties of pantropical water lilies， with seven compounds including alkanes， alkenes， terpenoid， benzenoid， esters， alcohols， and aldehydes in descending order of content. Among them， alkanes and alkenes were the categories with higher content， with an average proportion of 42.43% and 28.61%， respectively， but they had no obvious odor characteristics. 19 active substances of odor were further screened by the odor activity value （OAV）. Among them， the characteristic substances of odor that can be perceived by the odor activity value （OAV>1） were all terpenoids including α-ionone， β-ionone， trans-β-ionone and farnesene， among which ionone endowed water lilies with woody and sweet fragrance， while farnesene endowed water lilies with apple and typical floral fragrance. It is indicated that the five varieties of water lilies including ‘Blue Bird’， ‘Kara Sunshine’， ‘Golden Country’， ‘Ruby’， and ‘Pink Diamond’ screened based on the odor activity value are potential elite varieties for landscaping use and processing product.
The headspace solid-phase microextraction combined with gas chromatography-mass spectrometry （HS-SPEM-GC-MS） technology was used to detect volatile substances in 30 common cultivated varieties of pantropical water lilies to detect the volatile components， identify the aroma active substances， and screen the excellent aromatic varieties of water lilies. The results showed that a total of 60 volatile compounds were identified in the 30 varieties of pantropical water lilies， with seven compounds including alkanes， alkenes， terpenoid， benzenoid， esters， alcohols， and aldehydes in descending order of content. Among them， alkanes and alkenes were the categories with higher content， with an average proportion of 42.43% and 28.61%， respectively， but they had no obvious odor characteristics. 19 active substances of odor were further screened by the odor activity value （OAV）. Among them， the characteristic substances of odor that can be perceived by the odor activity value （OAV>1） were all terpenoids including α-ionone， β-ionone， trans-β-ionone and farnesene， among which ionone endowed water lilies with woody and sweet fragrance， while farnesene endowed water lilies with apple and typical floral fragrance. It is indicated that the five varieties of water lilies including ‘Blue Bird’， ‘Kara Sunshine’， ‘Golden Country’， ‘Ruby’， and ‘Pink Diamond’ screened based on the odor activity value are potential elite varieties for landscaping use and processing product.
2024,43(3):240-248
, DOI: 10.13300/j.cnki.hnlkxb.2024.03.025
Abstract:
The PhSPL9b gene was cloned to study the role of SPL （SQUAMOSA-promoter binding protein-like） transcription factor in the flowering transformation in petunia. Point mutation of the miR156/157 target site corresponding to the PhSPL9b gene was conducted to obtain rPhSPL9b. The overexpression vectors for 35S∶∶PhSPL9b and 35S∶∶rPhSPL9b were constructed and transformed into petunia and Arabidopsis. Transgenic plants of Arabidopsis overexpressing PhSPL9b or rPhSPL9b and transgenic plants of petunia overexpressing PhSPL9b were obtained. The results showed that overexpression PhSPL9b or rPhSPL9b， especially 35S∶∶rPhSPL9b， significantly reduced the number of rosettes and promoted flowering in Arabidopsis compared with the control （CK）. The phenotype of transgenic Arabidopsis with 35S∶∶rPhSPL9b was more obvious. Overexpression of PhSPL9b significantly promoted flowering in petunia. The results of analyses with RT-PCR and qRT-PCR showed that the expression level of PhSPL9b in transgenic lines with obvious phenotypes was significantly higher than that in the control. The results of transcription activation showed that PhSPL9b was a transcription factor with the function of activating transcription. It is indicated that the PhSPL9b gene in petunia plays an important regulatory role in flowering time， and its function is conserved. At the same time， it may affect plant flowering by transcriptionally activating the expression of downstream genes.
The PhSPL9b gene was cloned to study the role of SPL （SQUAMOSA-promoter binding protein-like） transcription factor in the flowering transformation in petunia. Point mutation of the miR156/157 target site corresponding to the PhSPL9b gene was conducted to obtain rPhSPL9b. The overexpression vectors for 35S∶∶PhSPL9b and 35S∶∶rPhSPL9b were constructed and transformed into petunia and Arabidopsis. Transgenic plants of Arabidopsis overexpressing PhSPL9b or rPhSPL9b and transgenic plants of petunia overexpressing PhSPL9b were obtained. The results showed that overexpression PhSPL9b or rPhSPL9b， especially 35S∶∶rPhSPL9b， significantly reduced the number of rosettes and promoted flowering in Arabidopsis compared with the control （CK）. The phenotype of transgenic Arabidopsis with 35S∶∶rPhSPL9b was more obvious. Overexpression of PhSPL9b significantly promoted flowering in petunia. The results of analyses with RT-PCR and qRT-PCR showed that the expression level of PhSPL9b in transgenic lines with obvious phenotypes was significantly higher than that in the control. The results of transcription activation showed that PhSPL9b was a transcription factor with the function of activating transcription. It is indicated that the PhSPL9b gene in petunia plays an important regulatory role in flowering time， and its function is conserved. At the same time， it may affect plant flowering by transcriptionally activating the expression of downstream genes.
2024,43(3):249-257
, DOI: 10.13300/j.cnki.hnlkxb.2024.03.026
Abstract:
To explore the spatial distribution characteristics of soil total nitrogen content in forest farm and its response to environmental factors，random forest model and Cubist model were used to establish a quantitative relationship between soil total nitrogen content and environmental covariates including elevation，normalized difference vegetation index，mean annual precipitation，mean annual temperature，y-coordinate and aspect at soil depths of 0-10，10-30 and 30-50 cm in Wangyedian experimental forest farm. Soil total nitrogen content of the area was predicted and mapped，and the controlling factors affecting the spatial variation of soil total nitrogen were analyzed. The results showed that the average content of soil total nitrogen at soil depth of 0-10，10-30 and 30-50 cm was 3.20，2.02 and 1.47 g/kg，respectively. It decreased with the increase of soil depth. The results of cross-validation showed that the R2 of the random forest model for predicting soil total nitrogen at the three soil depths was 0.59，0.42，and 0.39，respectively，better than the R2 of Cubist model with 0.56，0.38，and 0.34，respectively. The prediction accuracy of both models decreased with the increase of soil depth. The influence of various environmental factors on the spatial distribution of soil total nitrogen decreased with the increase of soil depth. From the prediction map of soil total nitrogen with the random forest model，the content of soil total nitrogen at different soil depth showed a spatial pattern of low in the western，northern，and central regions，and high in the southwestern，southeastern，and eastern regions. The uncertainty map showed that the random forest model had a low standard deviation in predicting the distribution of the content of soil total nitrogen. The elevation had the greatest impact on the content of soil total nitrogen，followed by the normalized difference vegetation index>mean annual precipitation>mean annual temperature>y-coordinate>aspect. It is indicated that the random forest model can serve as an effective method for predicting the content of soil total nitrogen at different soil depth in the forest farm.
To explore the spatial distribution characteristics of soil total nitrogen content in forest farm and its response to environmental factors，random forest model and Cubist model were used to establish a quantitative relationship between soil total nitrogen content and environmental covariates including elevation，normalized difference vegetation index，mean annual precipitation，mean annual temperature，y-coordinate and aspect at soil depths of 0-10，10-30 and 30-50 cm in Wangyedian experimental forest farm. Soil total nitrogen content of the area was predicted and mapped，and the controlling factors affecting the spatial variation of soil total nitrogen were analyzed. The results showed that the average content of soil total nitrogen at soil depth of 0-10，10-30 and 30-50 cm was 3.20，2.02 and 1.47 g/kg，respectively. It decreased with the increase of soil depth. The results of cross-validation showed that the R2 of the random forest model for predicting soil total nitrogen at the three soil depths was 0.59，0.42，and 0.39，respectively，better than the R2 of Cubist model with 0.56，0.38，and 0.34，respectively. The prediction accuracy of both models decreased with the increase of soil depth. The influence of various environmental factors on the spatial distribution of soil total nitrogen decreased with the increase of soil depth. From the prediction map of soil total nitrogen with the random forest model，the content of soil total nitrogen at different soil depth showed a spatial pattern of low in the western，northern，and central regions，and high in the southwestern，southeastern，and eastern regions. The uncertainty map showed that the random forest model had a low standard deviation in predicting the distribution of the content of soil total nitrogen. The elevation had the greatest impact on the content of soil total nitrogen，followed by the normalized difference vegetation index>mean annual precipitation>mean annual temperature>y-coordinate>aspect. It is indicated that the random forest model can serve as an effective method for predicting the content of soil total nitrogen at different soil depth in the forest farm.
2024,43(3):258-266
, DOI: 10.13300/j.cnki.hnlkxb.2024.03.027
Abstract:
To objectively assess the genetic diversity of Procambarus clarkii cultured populations in the vicinity of Nanning， Guangxi， three populations of P. clarkii from Nanning （AJ， LQ and SL）， and one population each from Jingzhou， Hubei （JZ） and Hukou， Jiangxi （HK） were collected. The level of genetic diversity was investigated using morphology and microsatellite markers. Morphological analysis showed that the total discrimination accuracy of female and male populations was 68.59% and 73.60%， respectively. Morphological clustering grouped the three Nanning populations into the same branch as the JZ population， indicating that the three Nanning populations had high morphological similarity. Microsatellite analysis revealed that the AJ population and LQ population had the highest genetic diversity， followed by the SL population and HK population. The genetic differentiation coefficient and genetic distance between the LQ population and SL population were the smallest. The results indicated that the populations of P. clarkii in Nanning， Guangxi had high genetic diversity， and that the introduction of P. clarkii from abroad or hybridization between different geographical populations may be an important way to enhance the genetic diversity of P. clarkii.
To objectively assess the genetic diversity of Procambarus clarkii cultured populations in the vicinity of Nanning， Guangxi， three populations of P. clarkii from Nanning （AJ， LQ and SL）， and one population each from Jingzhou， Hubei （JZ） and Hukou， Jiangxi （HK） were collected. The level of genetic diversity was investigated using morphology and microsatellite markers. Morphological analysis showed that the total discrimination accuracy of female and male populations was 68.59% and 73.60%， respectively. Morphological clustering grouped the three Nanning populations into the same branch as the JZ population， indicating that the three Nanning populations had high morphological similarity. Microsatellite analysis revealed that the AJ population and LQ population had the highest genetic diversity， followed by the SL population and HK population. The genetic differentiation coefficient and genetic distance between the LQ population and SL population were the smallest. The results indicated that the populations of P. clarkii in Nanning， Guangxi had high genetic diversity， and that the introduction of P. clarkii from abroad or hybridization between different geographical populations may be an important way to enhance the genetic diversity of P. clarkii.
2024,43(3):267-274
, DOI: 10.13300/j.cnki.hnlkxb.2024.03.028
Abstract:
Two-dimensional composite nanosheet materials （GO-MnO2 NSs） were prepared by combining graphene oxide （GO） with MnO2 nanosheets （MnO2 NSs） through π-π stacking force to develop new broad-spectrum nanomaterials for anti-animal borne virus infections. The morphology， structure， crystallinity and element valences of GO-MnO2 NSs were characterized by TEM， XRD， XPS. The cytotoxicity of GO-MnO2 NSs was tested by MTT. The results showed that the cell survival rate of 625 μg/mL GO-MnO2 NSs exceeded 85%. Porcine epidemic diarrhea virus （PEDV） was used as a model virus for coronavirus to study the effect of GO-MnO2 NSs on PEDV infection through concentration for 50% of maximal effect （EC50）， indirect immunofluorescence and western blot. The results showed that GO-MnO2 NSs had significant antiviral activity. It is indicated that GO-MnO2 NSs can eliminate the overexpression of reactive oxygen species caused by viral infection and inhibit cell apoptosis， while upregulating the expression of antiviral factors including interferon and interferon stimulating genes （ISGs） in cells as well， effectively inhibiting viral infection.
Two-dimensional composite nanosheet materials （GO-MnO2 NSs） were prepared by combining graphene oxide （GO） with MnO2 nanosheets （MnO2 NSs） through π-π stacking force to develop new broad-spectrum nanomaterials for anti-animal borne virus infections. The morphology， structure， crystallinity and element valences of GO-MnO2 NSs were characterized by TEM， XRD， XPS. The cytotoxicity of GO-MnO2 NSs was tested by MTT. The results showed that the cell survival rate of 625 μg/mL GO-MnO2 NSs exceeded 85%. Porcine epidemic diarrhea virus （PEDV） was used as a model virus for coronavirus to study the effect of GO-MnO2 NSs on PEDV infection through concentration for 50% of maximal effect （EC50）， indirect immunofluorescence and western blot. The results showed that GO-MnO2 NSs had significant antiviral activity. It is indicated that GO-MnO2 NSs can eliminate the overexpression of reactive oxygen species caused by viral infection and inhibit cell apoptosis， while upregulating the expression of antiviral factors including interferon and interferon stimulating genes （ISGs） in cells as well， effectively inhibiting viral infection.
2024,43(3):275-281
, DOI: 10.13300/j.cnki.hnlkxb.2024.03.029
Abstract:
In order to find effective microecological preparations for preventing necrotic enteritis （NE） in chickens in this study， a total of 120 one-day-old 817 chickens were randomly divided into four treatment groups. Control group and NE group （broiler model of NE established by infecting with Clostridium perfringens type G） were fed a basal diet. Probiotic group （Prob1） was fed a basal diet supplemented with 0.2% microbial agent 1， and probiotic group （Prob2） was fed a basal diet supplemented with 0.2% microbial agent 2. On days 14 to 16， broilers in Prob1， Prob2 and NE groups were treated with Clostridium perfringens （CP） by continuous gavage. The preventive effects of the two different Bacillus subtilis compound microbial preparations on NE of broilers were evaluated in the 23-day trial period. The results showed that， on day 17， the body weight of broilers in the NE group was lower than that of the control group. However， broilers in the Prob1 and Prob2 groups had a higher body weight at the 17th and 23rd days of the experiment compared to the NE group. The jejunal epithelial cells of broilers in the NE group were necrotic and exfoliated， with a shorter villus， deeper crypt， and smaller villus length and villus crypt ratio compared to the NE group treated with B. subtilis compound microbial preparation. The activities of T-SOD， T-AOC and AKP in the jejunal mucosa of broilers in the NE group were lower than those in the Control group. However， on day 17， the T-AOC and AKP activities in the jejunal mucosa of broilers in the Prob1 and Prob2 groups were significantly higher than those in the NE group， and the T-SOD activity of jejunal mucosa of broilers in Prob1 group was significantly higher than that in NE group. On day 23， the activities of T-SOD， T-AOC and AKP in jejunal mucosa of broilers in the Prob1 and Prob2 groups were higher than those in the NE group， and there were no significant differences. The content of MDA in jejunal mucosa of broilers in the NE group was higher than that in the control group， and the content of MDA in the Prob1 and Prob2 groups was lower than that in the NE group at the 17th and 23rd days. The gene expressions of intestinal tight junction protein CLDN1 and ZO-2 in the NE group were lower than those in the Control group， and there were significant differences on day 17 of the experiment. On the 17th and 23rd days of the experiment， expressions of the intestinal tight junction protein CLDN1 and ZO-2 genes in the Prob1 and Prob2 groups were higher than those in the NE group， and the expressions of ZO-1 gene in the Prob1 and Prob2 groups were significantly higher than those in the NE group. The results showed that adding B. subtilis compound microbial preparation to the diet could improve the growth and development of chickens with necrotizing enteritis， increase the antioxidant capacity and intestinal tight junction protein gene expression of broilers， and B. subtilis compound microbial preparation 1 had a better preventive effect on chicken necrotic enteritis.
In order to find effective microecological preparations for preventing necrotic enteritis （NE） in chickens in this study， a total of 120 one-day-old 817 chickens were randomly divided into four treatment groups. Control group and NE group （broiler model of NE established by infecting with Clostridium perfringens type G） were fed a basal diet. Probiotic group （Prob1） was fed a basal diet supplemented with 0.2% microbial agent 1， and probiotic group （Prob2） was fed a basal diet supplemented with 0.2% microbial agent 2. On days 14 to 16， broilers in Prob1， Prob2 and NE groups were treated with Clostridium perfringens （CP） by continuous gavage. The preventive effects of the two different Bacillus subtilis compound microbial preparations on NE of broilers were evaluated in the 23-day trial period. The results showed that， on day 17， the body weight of broilers in the NE group was lower than that of the control group. However， broilers in the Prob1 and Prob2 groups had a higher body weight at the 17th and 23rd days of the experiment compared to the NE group. The jejunal epithelial cells of broilers in the NE group were necrotic and exfoliated， with a shorter villus， deeper crypt， and smaller villus length and villus crypt ratio compared to the NE group treated with B. subtilis compound microbial preparation. The activities of T-SOD， T-AOC and AKP in the jejunal mucosa of broilers in the NE group were lower than those in the Control group. However， on day 17， the T-AOC and AKP activities in the jejunal mucosa of broilers in the Prob1 and Prob2 groups were significantly higher than those in the NE group， and the T-SOD activity of jejunal mucosa of broilers in Prob1 group was significantly higher than that in NE group. On day 23， the activities of T-SOD， T-AOC and AKP in jejunal mucosa of broilers in the Prob1 and Prob2 groups were higher than those in the NE group， and there were no significant differences. The content of MDA in jejunal mucosa of broilers in the NE group was higher than that in the control group， and the content of MDA in the Prob1 and Prob2 groups was lower than that in the NE group at the 17th and 23rd days. The gene expressions of intestinal tight junction protein CLDN1 and ZO-2 in the NE group were lower than those in the Control group， and there were significant differences on day 17 of the experiment. On the 17th and 23rd days of the experiment， expressions of the intestinal tight junction protein CLDN1 and ZO-2 genes in the Prob1 and Prob2 groups were higher than those in the NE group， and the expressions of ZO-1 gene in the Prob1 and Prob2 groups were significantly higher than those in the NE group. The results showed that adding B. subtilis compound microbial preparation to the diet could improve the growth and development of chickens with necrotizing enteritis， increase the antioxidant capacity and intestinal tight junction protein gene expression of broilers， and B. subtilis compound microbial preparation 1 had a better preventive effect on chicken necrotic enteritis.
2024,43(3):282-292
, DOI: 10.13300/j.cnki.hnlkxb.2024.03.030
Abstract:
Biochar is an efficient adsorption carrier for benzene pollutants， but the adsorption capacity of directly carbonized biochar for benzene pollutants is limited. Low-temperature air oxidation is effective in modifying the structure of biochar and enhancing its adsorption capacity of benzene pollutants. However， the adsorption behavior and mechanism of low-temperature air oxidation biochar for benzene pollutants still needs to be further clarified. Herein， low-temperature air oxidation biochar was prepared by a two-step activation method using bamboo chips as raw material and CaCl2 as activator. The adsorption processes and behaviors of low-temperature air oxidation biochar for four benzene pollutants including phenol， aniline， hydroquinone， and p-nitrophenol were deeply analyzed with comprehensive adsorption experiments， biochar structure characterization， and density flooding theory（DFT） calculations. The adsorption properties and mechanisms of oxygen-modified biochar for benzene pollutants were studied. The results showed that the adsorption performance of low-temperature air oxidation biochar for benzene pollutants was influenced by the synergistic effect of the pore structure and surface functional groups of biochar. Biochar regulated the adsorption and storage process of benzene pollutants at a spatial geometric scale through the pore filling effect of microporous structure. Oxygen atoms were assigned to the surface of the carbon skeleton of biochar in the form of hydroxyl， aldehyde and carboxyl groups after the oxidation of biochar by low temperature air. The electronic structure of the carbon skeleton was influenced by the electronic scale， modifying the adsorption position and type of interaction between the carbon skeleton and benzene pollutants. The adsorption capacities of biochar for benzene pollutants were significantly enhanced through mechanisms such as electrostatic attraction and hydrogen bonding. Among them， the hydrogen atoms of the hydroxyl and carboxyl groups in the carbon skeleton are easy to become donors of hydrogen bonds， while the oxygen atoms of the aldehyde group are easy to become acceptors of hydrogen bonds.
Biochar is an efficient adsorption carrier for benzene pollutants， but the adsorption capacity of directly carbonized biochar for benzene pollutants is limited. Low-temperature air oxidation is effective in modifying the structure of biochar and enhancing its adsorption capacity of benzene pollutants. However， the adsorption behavior and mechanism of low-temperature air oxidation biochar for benzene pollutants still needs to be further clarified. Herein， low-temperature air oxidation biochar was prepared by a two-step activation method using bamboo chips as raw material and CaCl2 as activator. The adsorption processes and behaviors of low-temperature air oxidation biochar for four benzene pollutants including phenol， aniline， hydroquinone， and p-nitrophenol were deeply analyzed with comprehensive adsorption experiments， biochar structure characterization， and density flooding theory（DFT） calculations. The adsorption properties and mechanisms of oxygen-modified biochar for benzene pollutants were studied. The results showed that the adsorption performance of low-temperature air oxidation biochar for benzene pollutants was influenced by the synergistic effect of the pore structure and surface functional groups of biochar. Biochar regulated the adsorption and storage process of benzene pollutants at a spatial geometric scale through the pore filling effect of microporous structure. Oxygen atoms were assigned to the surface of the carbon skeleton of biochar in the form of hydroxyl， aldehyde and carboxyl groups after the oxidation of biochar by low temperature air. The electronic structure of the carbon skeleton was influenced by the electronic scale， modifying the adsorption position and type of interaction between the carbon skeleton and benzene pollutants. The adsorption capacities of biochar for benzene pollutants were significantly enhanced through mechanisms such as electrostatic attraction and hydrogen bonding. Among them， the hydrogen atoms of the hydroxyl and carboxyl groups in the carbon skeleton are easy to become donors of hydrogen bonds， while the oxygen atoms of the aldehyde group are easy to become acceptors of hydrogen bonds.
2024,43(3):293-301
, DOI: 10.13300/j.cnki.hnlkxb.2024.03.031
Abstract:
A device and system for measuring storage capacity based on two-dimensional laser radar scanning was designed to improve the automation and intelligence level of measuring storage capacity of raw materials in storage tower and explore the feasibility of measuring storage capacity based on two-dimensional laser radar scanning. The system used RPLIDAR S1 two-dimensional laser radar scanning to obtain the original point cloud data of material with different storage capacity. The original point cloud was preprocessed with methods including coordinate transformation， overlapping point extraction， filtering， segmentation and others. The greedy projection triangulation algorithm was used to reconstruct the preprocessed point cloud in 3D to obtain a 3D model of the raw materials in the storage tower. The storage capacity of raw materials in the storage tower was obtained by combining the three-dimensional model of material and the bulk density of materials， thereby realizing automatic measurement of storage capacity. Maize was used to measure the amount stored in a small storage tower， and scan and measure different amounts stored to verify the accuracy of the model. The results showed that the average absolute error of the measurement results was 8.05 kg， with the average relative error of 1.52%. It is indicated that the method for measuring storage capacity based on two-dimensional laser radar scanning is feasible， with good stability and accuracy of measurement， and can meet the needs of production in practice. It will provide a new method and technical support for automatically measuring the storage capacity of raw materials in large storage tower.
A device and system for measuring storage capacity based on two-dimensional laser radar scanning was designed to improve the automation and intelligence level of measuring storage capacity of raw materials in storage tower and explore the feasibility of measuring storage capacity based on two-dimensional laser radar scanning. The system used RPLIDAR S1 two-dimensional laser radar scanning to obtain the original point cloud data of material with different storage capacity. The original point cloud was preprocessed with methods including coordinate transformation， overlapping point extraction， filtering， segmentation and others. The greedy projection triangulation algorithm was used to reconstruct the preprocessed point cloud in 3D to obtain a 3D model of the raw materials in the storage tower. The storage capacity of raw materials in the storage tower was obtained by combining the three-dimensional model of material and the bulk density of materials， thereby realizing automatic measurement of storage capacity. Maize was used to measure the amount stored in a small storage tower， and scan and measure different amounts stored to verify the accuracy of the model. The results showed that the average absolute error of the measurement results was 8.05 kg， with the average relative error of 1.52%. It is indicated that the method for measuring storage capacity based on two-dimensional laser radar scanning is feasible， with good stability and accuracy of measurement， and can meet the needs of production in practice. It will provide a new method and technical support for automatically measuring the storage capacity of raw materials in large storage tower.
2024,43(3):302-310
, DOI: 10.13300/j.cnki.hnlkxb.2024.03.032
Abstract:
A visual positioning scheme for an automatic water-based loading robot was designed to solve the problem of low automation in the water-based loading process for basket-packed eggs during the processing of poultry and egg products in China. This scheme combined YOLOv5s with methods of image processing to locate and recognize basket-packed eggs in complex environments. A relationship model between the optimal segmentation threshold T and the average grayscale value M of the image was established. The dynamic threshold segmentation method was used to segment the entire stack of eggs in the image. The two types of basket-packed egg stacks were distinguished based on the aspect ratio of the minimum bounding rectangle of the stack， with the recognition accuracy of the stack type of 100%. YOLOv5s was used to locate and identify the top egg baskets of the stack， with the recognition accuracy of the model of 98.48% and the time required to detect a single image of 0.005 4 s. The image was cropped based on the results of positioning output by YOLOv5s. The rotation angles of all egg baskets were calculated by using image segmentation to segment the bounding border of the egg baskets and detecting their edge information with the Canny operators， with an average angle error of 0.41°. The pose information of all the egg baskets in the basket-packed egg stack was obtained based on the height of the egg baskets. It is indicated that the method of positioning basket-packed eggs based on YOLOv5s and image processing can accurately identify the pose information of all egg baskets in the stack. This scheme has good robustness and feasibility， and can provide visual system technology support for the automatic loading robot of basket-packed poultry eggs.
A visual positioning scheme for an automatic water-based loading robot was designed to solve the problem of low automation in the water-based loading process for basket-packed eggs during the processing of poultry and egg products in China. This scheme combined YOLOv5s with methods of image processing to locate and recognize basket-packed eggs in complex environments. A relationship model between the optimal segmentation threshold T and the average grayscale value M of the image was established. The dynamic threshold segmentation method was used to segment the entire stack of eggs in the image. The two types of basket-packed egg stacks were distinguished based on the aspect ratio of the minimum bounding rectangle of the stack， with the recognition accuracy of the stack type of 100%. YOLOv5s was used to locate and identify the top egg baskets of the stack， with the recognition accuracy of the model of 98.48% and the time required to detect a single image of 0.005 4 s. The image was cropped based on the results of positioning output by YOLOv5s. The rotation angles of all egg baskets were calculated by using image segmentation to segment the bounding border of the egg baskets and detecting their edge information with the Canny operators， with an average angle error of 0.41°. The pose information of all the egg baskets in the basket-packed egg stack was obtained based on the height of the egg baskets. It is indicated that the method of positioning basket-packed eggs based on YOLOv5s and image processing can accurately identify the pose information of all egg baskets in the stack. This scheme has good robustness and feasibility， and can provide visual system technology support for the automatic loading robot of basket-packed poultry eggs.
Display Method:
Abstract:
Microplastics are an emerging pollutant that poses a potential environmental risk to soil ecosystems due to the widespread use and improper handling of plastic materials. Microplastics provide new habitats for microorganisms in the soil and form a unique ecosystem—plastisphere. Due to the special properties of artificial plastics, it is not easy to degrade in the soil environment, which makes the plastisphere pose a serious and lasting ecological threat to the original soil environment. However, recent research on the plastisphere has focused on aquatic ecosystems. Understanding of the effects of soil plastisphere on microorganisms, microplastics, and the combined effects of soil environment and other pollutants is still very limited. This paper reviews the research progress on the ecological risks of the plastisphere as a new habitat for soil microorganisms. This paper mainly discusses the selection effect of soil plastisphere on microorganisms and the migration and transformation of microplastics, the changes of soil structure and soil carbon cycle caused by soil plastisphere, and the combined effect with other environmental pollutants. The purpose of this study is to summarize the mechanism of interaction between microorganisms and microplastics in the soil plastisphere and the subsequent ecological effects, and to provide valuable guidance for future research on the plastisphere of soil ecosystems.
Microplastics are an emerging pollutant that poses a potential environmental risk to soil ecosystems due to the widespread use and improper handling of plastic materials. Microplastics provide new habitats for microorganisms in the soil and form a unique ecosystem—plastisphere. Due to the special properties of artificial plastics, it is not easy to degrade in the soil environment, which makes the plastisphere pose a serious and lasting ecological threat to the original soil environment. However, recent research on the plastisphere has focused on aquatic ecosystems. Understanding of the effects of soil plastisphere on microorganisms, microplastics, and the combined effects of soil environment and other pollutants is still very limited. This paper reviews the research progress on the ecological risks of the plastisphere as a new habitat for soil microorganisms. This paper mainly discusses the selection effect of soil plastisphere on microorganisms and the migration and transformation of microplastics, the changes of soil structure and soil carbon cycle caused by soil plastisphere, and the combined effect with other environmental pollutants. The purpose of this study is to summarize the mechanism of interaction between microorganisms and microplastics in the soil plastisphere and the subsequent ecological effects, and to provide valuable guidance for future research on the plastisphere of soil ecosystems.
Abstract:
To investigate the physiological function of thiamine I in myxobacteria, Corallococcus sp. EGB, Myxococcus xanthus DK1622 and Cystobacter sp. 1404 were selected and employed as research subjects in this study. Genes related to thiamine synthesis pathway in the genomes of three stains and their relationships with the growth and development of strains were studied. The results showed that all three strains’ genomes contained complete thiamine synthesis pathway and genes related to thiamine synthesis precursor pyrimidine (HMP) recovery, but did not contain genes related to thiamine or its precursor thiazole recovery. The TPP-riboswitch present upstream of the HMP synthase gene thiC can regulate the transcriptional level of the thiC gene according to the thiamine concentration. Mutant CL1006 and CL1007 were constructed by inserting the thiC gene into strain DK1622 and thiaminase I knockout mutant CL1003, respectively. CL1006 required additional thiamine or HMP for growth in thiamine-free medium, with a significant increase of 9.0% in colony diameter compared to the thiamine-treated group when HMP was added alone. CL1007 could only grow on medium supplemented with HMP, and the addition of intact thiamine alone could not restore its growth. However, when both CcThi1 and thiamine were added, the growth of CL1007 was restored. These results indicate that myxobacteria do not directly utilize exogenous thiamine but could utilize pyrimidine precursors produced by decomposing thiamine through thiaminase I. This finding lays a foundation for elucidating the physiological function of thiamine I in myxobacteria and in-depth analysis of the ecological regulation mechanism of myxobacteria on microbial communities.
To investigate the physiological function of thiamine I in myxobacteria, Corallococcus sp. EGB, Myxococcus xanthus DK1622 and Cystobacter sp. 1404 were selected and employed as research subjects in this study. Genes related to thiamine synthesis pathway in the genomes of three stains and their relationships with the growth and development of strains were studied. The results showed that all three strains’ genomes contained complete thiamine synthesis pathway and genes related to thiamine synthesis precursor pyrimidine (HMP) recovery, but did not contain genes related to thiamine or its precursor thiazole recovery. The TPP-riboswitch present upstream of the HMP synthase gene thiC can regulate the transcriptional level of the thiC gene according to the thiamine concentration. Mutant CL1006 and CL1007 were constructed by inserting the thiC gene into strain DK1622 and thiaminase I knockout mutant CL1003, respectively. CL1006 required additional thiamine or HMP for growth in thiamine-free medium, with a significant increase of 9.0% in colony diameter compared to the thiamine-treated group when HMP was added alone. CL1007 could only grow on medium supplemented with HMP, and the addition of intact thiamine alone could not restore its growth. However, when both CcThi1 and thiamine were added, the growth of CL1007 was restored. These results indicate that myxobacteria do not directly utilize exogenous thiamine but could utilize pyrimidine precursors produced by decomposing thiamine through thiaminase I. This finding lays a foundation for elucidating the physiological function of thiamine I in myxobacteria and in-depth analysis of the ecological regulation mechanism of myxobacteria on microbial communities.
Abstract:
Measure and analyze the level of urban-rural integration in counties of Jiangsu Province, and explore the influencing factors of urban-rural integration in counties of Jiangsu Province, so as to provide policy inspiration and scientific basis for promoting urban-rural integration development in Jiangsu Province and other regions. By constructing an index evaluation system for urban-rural integration, this paper combined the natural discontinuation method, kernel density estimation method and exploratory spatial analysis method to describe the spatial and temporal distribution and evolution characteristics of urban-rural integration in Jiangsu Province from 2013 to 2021, and identified the internal obstacle factors and external driving factors of urban-rural integration in Jiangsu Province based on the obstacle degree model and geographical detector model. The results show that: (1) Since 2013, the level of Rural-urban integration in Jiangsu Province has continued to rise, but the level of rural-urban integration among counties is different and the difference is still expanding; By 2021, the integration index of each dimension in descending order is: social integration, ecological integration, spatial integration, economic integration, population integration; The regional integration index from high to low is South Jiangsu, Central Jiangsu and North Jiangsu. There is a positive global spatial correlation in county urban-rural integration in Jiangsu Province, and the local spatial distribution pattern shows high-high agglomeration and low-low agglomeration types, with low-level agglomeration taking the main part. (2) On the whole, the low level of industrial structure and employment structure, as well as the deviation of industrial structure and employment structure, are the main internal obstacles to the urban-rural integration development of counties in Jiangsu Province. From the perspective of different regions, there are differences in the resistance of each obstacle factor in Southern Jiangsu, Central Jiangsu and Northern Jiangsu. (3) Digital technology is an important external driving force for urban-rural integration at county level in Jiangsu Province. Among them, the digitalization of rural economy is the most obvious driving force for urban-rural integration, and digital marketing is the main driving path. This study believes that the communication and interaction between counties should be strengthened to promote the linkage and balanced development among counties. Optimize the industrial structure and employment structure of the county simultaneously, according to local conditions, aim at the advantages and disadvantages of each county, and break the obstacles of urban-rural integration in Jiangsu Province; We will focus on supporting the application of digital technology in the rural economy, cultivate new forms of business represented by rural e-commerce, and help the integration of urban and rural areas at the county level to a new level.
Measure and analyze the level of urban-rural integration in counties of Jiangsu Province, and explore the influencing factors of urban-rural integration in counties of Jiangsu Province, so as to provide policy inspiration and scientific basis for promoting urban-rural integration development in Jiangsu Province and other regions. By constructing an index evaluation system for urban-rural integration, this paper combined the natural discontinuation method, kernel density estimation method and exploratory spatial analysis method to describe the spatial and temporal distribution and evolution characteristics of urban-rural integration in Jiangsu Province from 2013 to 2021, and identified the internal obstacle factors and external driving factors of urban-rural integration in Jiangsu Province based on the obstacle degree model and geographical detector model. The results show that: (1) Since 2013, the level of Rural-urban integration in Jiangsu Province has continued to rise, but the level of rural-urban integration among counties is different and the difference is still expanding; By 2021, the integration index of each dimension in descending order is: social integration, ecological integration, spatial integration, economic integration, population integration; The regional integration index from high to low is South Jiangsu, Central Jiangsu and North Jiangsu. There is a positive global spatial correlation in county urban-rural integration in Jiangsu Province, and the local spatial distribution pattern shows high-high agglomeration and low-low agglomeration types, with low-level agglomeration taking the main part. (2) On the whole, the low level of industrial structure and employment structure, as well as the deviation of industrial structure and employment structure, are the main internal obstacles to the urban-rural integration development of counties in Jiangsu Province. From the perspective of different regions, there are differences in the resistance of each obstacle factor in Southern Jiangsu, Central Jiangsu and Northern Jiangsu. (3) Digital technology is an important external driving force for urban-rural integration at county level in Jiangsu Province. Among them, the digitalization of rural economy is the most obvious driving force for urban-rural integration, and digital marketing is the main driving path. This study believes that the communication and interaction between counties should be strengthened to promote the linkage and balanced development among counties. Optimize the industrial structure and employment structure of the county simultaneously, according to local conditions, aim at the advantages and disadvantages of each county, and break the obstacles of urban-rural integration in Jiangsu Province; We will focus on supporting the application of digital technology in the rural economy, cultivate new forms of business represented by rural e-commerce, and help the integration of urban and rural areas at the county level to a new level.
Abstract:
Aim: Arthropod diversity is the most important component of urban biodiversity. Clarifying the relationship between arthropod diversity and green space microenvironmental factors can promote the stability and sustainable development of urban green space ecosystems, which is of great significance. Methods: This article used the interceptor collection method to collect arthropod communities from six small and medium-sized parks within the third ring road of Beijing. Pearson correlation analysis, regression analysis, and principal component analysis (PCA) were used to explore the relationship between green space microenvironmental factors and the diversity of arthropod communities. Results: (1) Aphididae are the dominant family in garden green spaces, accounting for 52.12% of the total abundance; Diaeretiella rapae and Semidalis aleyrodiformes are the dominant species of natural enemy insects, accounting for 27.73% and 23.92% of the total abundance, respectively. There are significant differences in the abundance, abundance, and Shannon Weiner diversity index of arthropod communities among different plots. (2) Pearson correlation analysis showed that the areas, richness and Shannon Wiener index of flowering plants were significantly positively correlated with the abundance of arthropods (P < 0.001), the richness (P < 0.001) and the abundance (P < 0.001) of natural enemy insects, while they were significantly negatively correlated with the Shannon Wiener index and evenness index of arthropod communities (P < 0.001) which is supposed that induce by dosage applicating; and the frequency and dosage ratio of application were significantly positively correlated with the abundance of arthropod communities (P < 0.001). It is deduced that the negative correlations and the positive correlation in abundance was induced by the aphid resurgence caused by dosage applicating. (3) The results of principal component analysis showed that the main microenvironmental factors affecting the diversity of arthropods in green spaces were the ratio of pesticide dosage, the area of flowering plants, the frequency of pesticide application, the evenness of flowering plants, the Shannon Wiener diversity of flowering plants, and the abundance of flowering plants. (4) The RDA analysis results showed that the area, evenness, Shannon Wiener diversity and abundance of flowering plants were significantly positively correlated with the abundance of arthropods and their natural enemies, and significantly negatively correlated with arthropod diversity. The comprehensive ranking results show that the top three factors with the greatest influence are the dosage applicating ratio, the flowering plant area and the dosage applicating frequency. Conclusion: The research results have preliminarily clarified the microenvironmental factors and their impacts on the diversity of arthropods in park green spaces, which has reference significance for promoting the protection of urban green space biodiversity.
Aim: Arthropod diversity is the most important component of urban biodiversity. Clarifying the relationship between arthropod diversity and green space microenvironmental factors can promote the stability and sustainable development of urban green space ecosystems, which is of great significance. Methods: This article used the interceptor collection method to collect arthropod communities from six small and medium-sized parks within the third ring road of Beijing. Pearson correlation analysis, regression analysis, and principal component analysis (PCA) were used to explore the relationship between green space microenvironmental factors and the diversity of arthropod communities. Results: (1) Aphididae are the dominant family in garden green spaces, accounting for 52.12% of the total abundance; Diaeretiella rapae and Semidalis aleyrodiformes are the dominant species of natural enemy insects, accounting for 27.73% and 23.92% of the total abundance, respectively. There are significant differences in the abundance, abundance, and Shannon Weiner diversity index of arthropod communities among different plots. (2) Pearson correlation analysis showed that the areas, richness and Shannon Wiener index of flowering plants were significantly positively correlated with the abundance of arthropods (P < 0.001), the richness (P < 0.001) and the abundance (P < 0.001) of natural enemy insects, while they were significantly negatively correlated with the Shannon Wiener index and evenness index of arthropod communities (P < 0.001) which is supposed that induce by dosage applicating; and the frequency and dosage ratio of application were significantly positively correlated with the abundance of arthropod communities (P < 0.001). It is deduced that the negative correlations and the positive correlation in abundance was induced by the aphid resurgence caused by dosage applicating. (3) The results of principal component analysis showed that the main microenvironmental factors affecting the diversity of arthropods in green spaces were the ratio of pesticide dosage, the area of flowering plants, the frequency of pesticide application, the evenness of flowering plants, the Shannon Wiener diversity of flowering plants, and the abundance of flowering plants. (4) The RDA analysis results showed that the area, evenness, Shannon Wiener diversity and abundance of flowering plants were significantly positively correlated with the abundance of arthropods and their natural enemies, and significantly negatively correlated with arthropod diversity. The comprehensive ranking results show that the top three factors with the greatest influence are the dosage applicating ratio, the flowering plant area and the dosage applicating frequency. Conclusion: The research results have preliminarily clarified the microenvironmental factors and their impacts on the diversity of arthropods in park green spaces, which has reference significance for promoting the protection of urban green space biodiversity.
Abstract:
The reduction in chemical fertilizer combined with organic amendments is an effective way of realizing the green and sustainable development of agriculture in China. In this paper, we studied the effects of reduced fertilizer application combined with straw return and biochar on rice yield, nutrient absorption and soil carbon to provide a scientific basis for optimizing nutrient resource management in the region's farmland and the resource utilization of straw. A field plot experiment was carried out for two consecutive years in the lime concretion black soil area. Five treatments were set up, including no fertilizer (CK), conventional application of chemical fertilizer (100%NPK), 20% reduction of chemical fertilizer (80%NPK), 20% reduction of chemical fertilizer plus biochar (80%NPK+S), 20% reduction of chemical fertilizer plus straw returning (80%NPK+B). The rice grain yields, aboveground biomass, the content of N, P and K in grain and straw, soil total organic carbon (TOC) and microbial biomass carbon (MBC) were measured and analyzed. The results showed that biochar and straw returning combined with chemical fertilizer reduction by 20% had shown an effective increase on the grain yield and aboveground biomass of rice, in which the effect of biochar exhibited better effect than that of straw returning. The average yield and aboveground biomass of rice in 80%NPK+B treatment was 5.2% and 4.7% higher than those in 100%NPK, and 7.9% and 7.2% higher than those in 80%NPK, respectively. Compared with 100%NPK treatment, the average yield and aboveground biomass of rice in 80%NPK+B treatment increased by 3.4% and 3.0%, respectively. In terms of nutrient uptake by rice, the addition of biochar combined with chemical fertilizer reduction by 20% improved efficiently the nitrogen, phosphorus and potassium absorption of rice, which were 10.4%、7.2% and 20.0% higher over 100%NPK treatment, respectively. The addition of straw combined with chemical fertilizer reduction by 20% could efficiently improve the nitrogen and potassium absorption of rice, while reduce the phosphorus absorption at the same time. It was also found that the application of biochar or straw combined with chemical fertilizer reduction by 20% promoted the accumulation of soil total organic carbon and significantly enhanced microbial biomass carbon at maturity. The benefit of biochar application was better than that of straw retuning in increasing total organic carbon content, while straw retuning performs better than that of biochar in improving microbial biomass carbon content. In conclusion, biochar application combined with chemical fertilizer reduction by 20% or straw returning combined with nitrogen and potassium fertilizer reduction by 20% has the potential to increase or maintain the same levels of rice yields, enhance nutrient absorption, and benefit the fixation of soil organic carbon and in lime concretion black soil along the Huai River.
The reduction in chemical fertilizer combined with organic amendments is an effective way of realizing the green and sustainable development of agriculture in China. In this paper, we studied the effects of reduced fertilizer application combined with straw return and biochar on rice yield, nutrient absorption and soil carbon to provide a scientific basis for optimizing nutrient resource management in the region's farmland and the resource utilization of straw. A field plot experiment was carried out for two consecutive years in the lime concretion black soil area. Five treatments were set up, including no fertilizer (CK), conventional application of chemical fertilizer (100%NPK), 20% reduction of chemical fertilizer (80%NPK), 20% reduction of chemical fertilizer plus biochar (80%NPK+S), 20% reduction of chemical fertilizer plus straw returning (80%NPK+B). The rice grain yields, aboveground biomass, the content of N, P and K in grain and straw, soil total organic carbon (TOC) and microbial biomass carbon (MBC) were measured and analyzed. The results showed that biochar and straw returning combined with chemical fertilizer reduction by 20% had shown an effective increase on the grain yield and aboveground biomass of rice, in which the effect of biochar exhibited better effect than that of straw returning. The average yield and aboveground biomass of rice in 80%NPK+B treatment was 5.2% and 4.7% higher than those in 100%NPK, and 7.9% and 7.2% higher than those in 80%NPK, respectively. Compared with 100%NPK treatment, the average yield and aboveground biomass of rice in 80%NPK+B treatment increased by 3.4% and 3.0%, respectively. In terms of nutrient uptake by rice, the addition of biochar combined with chemical fertilizer reduction by 20% improved efficiently the nitrogen, phosphorus and potassium absorption of rice, which were 10.4%、7.2% and 20.0% higher over 100%NPK treatment, respectively. The addition of straw combined with chemical fertilizer reduction by 20% could efficiently improve the nitrogen and potassium absorption of rice, while reduce the phosphorus absorption at the same time. It was also found that the application of biochar or straw combined with chemical fertilizer reduction by 20% promoted the accumulation of soil total organic carbon and significantly enhanced microbial biomass carbon at maturity. The benefit of biochar application was better than that of straw retuning in increasing total organic carbon content, while straw retuning performs better than that of biochar in improving microbial biomass carbon content. In conclusion, biochar application combined with chemical fertilizer reduction by 20% or straw returning combined with nitrogen and potassium fertilizer reduction by 20% has the potential to increase or maintain the same levels of rice yields, enhance nutrient absorption, and benefit the fixation of soil organic carbon and in lime concretion black soil along the Huai River.
Abstract:
Prokaryotic Argonautes (pAgos) are an emerging class of programmable nucleases that are considered to be more flexible than existing CRISPR–Cas systems, showing great potential for biotechnology. The current applications of pAgos mainly include molecular diagnostics and in vitro DNA assembly. However, early research primarily focused on thermophilic pAgos. To enable in vivo biotechnological applications such as genome editing, researchers have gradually shifted their focus to mesophilic organisms. Here, this review will discuss the known pAgos and their various applications, as well as the challenges and potential strategies for applying pAgos in prokaryotic and eukaryotic organisms.
Prokaryotic Argonautes (pAgos) are an emerging class of programmable nucleases that are considered to be more flexible than existing CRISPR–Cas systems, showing great potential for biotechnology. The current applications of pAgos mainly include molecular diagnostics and in vitro DNA assembly. However, early research primarily focused on thermophilic pAgos. To enable in vivo biotechnological applications such as genome editing, researchers have gradually shifted their focus to mesophilic organisms. Here, this review will discuss the known pAgos and their various applications, as well as the challenges and potential strategies for applying pAgos in prokaryotic and eukaryotic organisms.
Abstract:
In order to simplify the detection steps of multi-pesticide residues in bananas, shorten the detection time and reduce the analysis cost, a rapid and accurate detection method for 11 common pesticides in bananas was established by solid-phase microextraction combined with ultra-performance chromatography-tandem mass spectrometry (SPME-UPLC-MS/MS). Two kinds of SPME fibers with extensive coverage capability and large extraction capacity were prepared by using cotton swabs as support carriers. The pesticides were extracted from diluted banana homogenate samples in a dual-fiber mode and desorbed by a little of methanol. The desorption solution was directly analyzed by UPLC-MS/MS and the analytes were quantified by matrix-matched external standard method. The results showed that the limits of detection of 11 pesticides in banana were 0.23~2.43 μg/kg, and the limits of quantification were 0.68~7.36 μg/kg. The recoveries were 86.2%~109.8% and the relative standard deviations were 0.6%~11.2%, which is in accordance with the relevant regulations of pesticide determination. The results indicate that the new method is simple, rapid, sensitive, accurate and low-cost, and can meet the requirements of rapid detection of multi-pesticide residues in bananas.
In order to simplify the detection steps of multi-pesticide residues in bananas, shorten the detection time and reduce the analysis cost, a rapid and accurate detection method for 11 common pesticides in bananas was established by solid-phase microextraction combined with ultra-performance chromatography-tandem mass spectrometry (SPME-UPLC-MS/MS). Two kinds of SPME fibers with extensive coverage capability and large extraction capacity were prepared by using cotton swabs as support carriers. The pesticides were extracted from diluted banana homogenate samples in a dual-fiber mode and desorbed by a little of methanol. The desorption solution was directly analyzed by UPLC-MS/MS and the analytes were quantified by matrix-matched external standard method. The results showed that the limits of detection of 11 pesticides in banana were 0.23~2.43 μg/kg, and the limits of quantification were 0.68~7.36 μg/kg. The recoveries were 86.2%~109.8% and the relative standard deviations were 0.6%~11.2%, which is in accordance with the relevant regulations of pesticide determination. The results indicate that the new method is simple, rapid, sensitive, accurate and low-cost, and can meet the requirements of rapid detection of multi-pesticide residues in bananas.
Abstract:
Leucine-rich repeat (LRR) is widely present in various organisms, mainly involved in the innate immune process. To further study its mechanism, it is necessary to prepare an antibody that can specifically recognize LRR structure. Chlamydomonas reinhardtii as a model organism, the physicochemical properties of CrLRR-1 protein including secondary structure, hydrophilicity, immunogenicity were predicted and analyzed by bioinformatics. CrLRR-1 specific peptide was designed and synthesized, which coupled with keyhole limpet hemocyanin (KLH) was used to immunize New Zealand white rabbits. The antiserum titer was determined to be 1:512 000 by indirect ELISA and the antiserum was purified by Protein A and antigen affinity. The results of western blotting and immunofluorescence showed the polyclonal antibody could specifically recognize to LRR-1 in C. reinhardtii, and the CrLRR-1 protein is mainly located in the cell membrane. In conclusion, polyclonal antibody against CrLRR-1 protein was successfully prepared.
Leucine-rich repeat (LRR) is widely present in various organisms, mainly involved in the innate immune process. To further study its mechanism, it is necessary to prepare an antibody that can specifically recognize LRR structure. Chlamydomonas reinhardtii as a model organism, the physicochemical properties of CrLRR-1 protein including secondary structure, hydrophilicity, immunogenicity were predicted and analyzed by bioinformatics. CrLRR-1 specific peptide was designed and synthesized, which coupled with keyhole limpet hemocyanin (KLH) was used to immunize New Zealand white rabbits. The antiserum titer was determined to be 1:512 000 by indirect ELISA and the antiserum was purified by Protein A and antigen affinity. The results of western blotting and immunofluorescence showed the polyclonal antibody could specifically recognize to LRR-1 in C. reinhardtii, and the CrLRR-1 protein is mainly located in the cell membrane. In conclusion, polyclonal antibody against CrLRR-1 protein was successfully prepared.
Abstract:
LysM receptor-like kinases (LysM-RLKs) belong to the multi-gene family whose extracellular domains are directly involved in the perception of glycosyl compounds including chitin, peptidoglycans, and lipochitooligosaccharides, thereby activating pathways of plant immunity or symbiotic signal transduction. The function of the first LysM receptor gene, LYK3, in the model legume Medicago truncata was characterized in 2003. Subsequently, the function of more and more LysM receptor kinases was identified. This article provided a detailed enumeration and functional characterization of the LysM-RLK family in M. truncatula. The progress on studying LysM receptor kinase family in nodulation symbiosis, mycorrhizal symbiosis, and immune perception of Medicago truncata was summarized. It is indicated that the expansion of the number of LysM-RLKs genes within the M. truncatula has led to functional differentiation, but there is a phenomenon of functional redundancy among some genes as well. In addition, a close cross-linking between immune and symbiotic signals at the level of receptor perception mediated by LysM-RLKs was revealed. It will provide effective references and perspectives for further studying LysM-RLKs genes in M. truncatula.
LysM receptor-like kinases (LysM-RLKs) belong to the multi-gene family whose extracellular domains are directly involved in the perception of glycosyl compounds including chitin, peptidoglycans, and lipochitooligosaccharides, thereby activating pathways of plant immunity or symbiotic signal transduction. The function of the first LysM receptor gene, LYK3, in the model legume Medicago truncata was characterized in 2003. Subsequently, the function of more and more LysM receptor kinases was identified. This article provided a detailed enumeration and functional characterization of the LysM-RLK family in M. truncatula. The progress on studying LysM receptor kinase family in nodulation symbiosis, mycorrhizal symbiosis, and immune perception of Medicago truncata was summarized. It is indicated that the expansion of the number of LysM-RLKs genes within the M. truncatula has led to functional differentiation, but there is a phenomenon of functional redundancy among some genes as well. In addition, a close cross-linking between immune and symbiotic signals at the level of receptor perception mediated by LysM-RLKs was revealed. It will provide effective references and perspectives for further studying LysM-RLKs genes in M. truncatula.
Abstract:
To address the challenge of handling high moisture content sediment sludge in the solid liquid separator of pond Juanyang mode, this study conducted dewatering experiments using a "coagulation + plate and frame filtration" approach. Initially, Poly Aluminum Sulfate (PAS), Poly Silicate Aluminum Ferric (PSAF), and Poly Ferric Sulfate(PFS) were selected as experimental factors for sludge coagulation tests, with sludge specific resistance (SRF) and pollution properties of filtrate as experimental indicators. Subsequently, factors such as types of filter cloth, dosage of the selected coagulant, filtration pressure, and dwell time were considered for plate and frame filtration dewatering experiments on sediment sludge, with sludge dewatering rate (DR) and pollution properties of filtrate as experimental indicators. Experimental results revealed that PAS, PSAF, and PFS exhibit significant conditioning effects on the sludge. The optimal effect is achieved when the PSAF dosage is 2% of the dry mass of the sludge, resulting in a reduction of sludge specific resistance by 97.43% to 2.08×10^12m/kg, with the Nemerow index of filtrate was 3.61. Plate and frame filtration demonstrated good dewatering performance on the sludge conditioned with PSAF. By using polyester 621 filter cloth, a 2% addition rate of PSAF of the sludge dry mass, a filtration pressure of 0.3 MPa, and and a dwell time of 10 minutes, the plate and frame filtration achieved effective dewatering, reducing the sludge moisture content to 70.98% and a dewatering rate of 80.94%, with the Nemerow index was 4.54. Therefore, the approach of plate and frame filtration after PSAF conditioning can serve as an effective dewatering technique for sediment sludge in pond Juanyang systems, aiming to reduce sludge volume for easier transportation and storage.
To address the challenge of handling high moisture content sediment sludge in the solid liquid separator of pond Juanyang mode, this study conducted dewatering experiments using a "coagulation + plate and frame filtration" approach. Initially, Poly Aluminum Sulfate (PAS), Poly Silicate Aluminum Ferric (PSAF), and Poly Ferric Sulfate(PFS) were selected as experimental factors for sludge coagulation tests, with sludge specific resistance (SRF) and pollution properties of filtrate as experimental indicators. Subsequently, factors such as types of filter cloth, dosage of the selected coagulant, filtration pressure, and dwell time were considered for plate and frame filtration dewatering experiments on sediment sludge, with sludge dewatering rate (DR) and pollution properties of filtrate as experimental indicators. Experimental results revealed that PAS, PSAF, and PFS exhibit significant conditioning effects on the sludge. The optimal effect is achieved when the PSAF dosage is 2% of the dry mass of the sludge, resulting in a reduction of sludge specific resistance by 97.43% to 2.08×10^12m/kg, with the Nemerow index of filtrate was 3.61. Plate and frame filtration demonstrated good dewatering performance on the sludge conditioned with PSAF. By using polyester 621 filter cloth, a 2% addition rate of PSAF of the sludge dry mass, a filtration pressure of 0.3 MPa, and and a dwell time of 10 minutes, the plate and frame filtration achieved effective dewatering, reducing the sludge moisture content to 70.98% and a dewatering rate of 80.94%, with the Nemerow index was 4.54. Therefore, the approach of plate and frame filtration after PSAF conditioning can serve as an effective dewatering technique for sediment sludge in pond Juanyang systems, aiming to reduce sludge volume for easier transportation and storage.
Abstract:
This article briefly outlines the research progress of precision vegetable seeding technology and equipment both domestically and internationally. It analyzes the general situation of vegetable production and major seeding equipment worldwide, emphasizing the key technological equipment and the dynamics of intelligent mechanized direct seeding in vegetables, including precision and variable seed metering, seedbed formation, seed furrow shaping, and control detection. The study clarifies the research priorities and challenges in mechanized direct seeding of vegetables, summarizes the optimized design methods for the seed metering system and seedbed forming system of precision vegetable seeders, and identifies the foundation and core of precision mechanized direct seeding of vegetables. It explores the key factors affecting seeding accuracy and elucidates the implementation method of precision live streaming technology for vegetable seeds from the perspective of precision key technology and equipment analysis. Based on the structures and principles of different metering devices, it elucidates the factors influencing the stability of seeding depth and the realization methods of precision seeding in mechanized precision vegetable planting. After systematically summarizing and analyzing the characteristics of vegetable cultivation in China and the development trends of precision direct seeding technology and equipment, the article points out the current technical difficulties in precision vegetable seeding and proposes that the research focus should be on breaking through the methods of precision and variable seed metering, as well as high-speed and efficient seeding. Furthermore, by analyzing the current development status of precision seeders both domestically and internationally, the article anticipates the future development trends of precision direct seeding technology for vegetables, providing a reference for the theoretical research and the development of precision vegetable seeders in China, which holds significant importance for the advancement of high-speed precision seeding technology in the country.
This article briefly outlines the research progress of precision vegetable seeding technology and equipment both domestically and internationally. It analyzes the general situation of vegetable production and major seeding equipment worldwide, emphasizing the key technological equipment and the dynamics of intelligent mechanized direct seeding in vegetables, including precision and variable seed metering, seedbed formation, seed furrow shaping, and control detection. The study clarifies the research priorities and challenges in mechanized direct seeding of vegetables, summarizes the optimized design methods for the seed metering system and seedbed forming system of precision vegetable seeders, and identifies the foundation and core of precision mechanized direct seeding of vegetables. It explores the key factors affecting seeding accuracy and elucidates the implementation method of precision live streaming technology for vegetable seeds from the perspective of precision key technology and equipment analysis. Based on the structures and principles of different metering devices, it elucidates the factors influencing the stability of seeding depth and the realization methods of precision seeding in mechanized precision vegetable planting. After systematically summarizing and analyzing the characteristics of vegetable cultivation in China and the development trends of precision direct seeding technology and equipment, the article points out the current technical difficulties in precision vegetable seeding and proposes that the research focus should be on breaking through the methods of precision and variable seed metering, as well as high-speed and efficient seeding. Furthermore, by analyzing the current development status of precision seeders both domestically and internationally, the article anticipates the future development trends of precision direct seeding technology for vegetables, providing a reference for the theoretical research and the development of precision vegetable seeders in China, which holds significant importance for the advancement of high-speed precision seeding technology in the country.
Abstract:
A salt-tolerant strain SF-18 with significant antibacterial activity was isolated and screened from soil samples in Aksu saline alkali land, Xinjiang. The SF-18 strain has a significant inhibitory effect on Staphylococcus aureus and Verticillium dahlia and could grow in the broth containing 18% NaCl. Using the Verticillium dahlia as an indicator strain, the SF-18 cell-free fermentation supernatant showed stable antibacterial activity within the range of -20℃-80℃, and pH 5-pH 12 environments. The strain was identified as belonging to the genus Bacillus based on the 16S rDNA gene and gyrB gene sequences. Whole gene sequence analysis showed that there were 480 genes of the strain involved in the metabolism of multiple carbon sources. The strain contained genes encoding the alimine and trehalose which are related to stress resistance. The prediction analysis of secondary metabolites showed that strain SF-18 contained gene clusters related to synthesize a various of resistant compounds, such as bacillaene, bacillibactin, mersacidin, fengycin, zwittermicin, as well as genes related to glucanase and chitinase that can hydrolyze the cell wall of pathogen. Therefore, it is speculated that strain SF-18 can produce antibacterial secondary metabolites and related degrading enzymes to prevent and control plant disease, showing good application prospects in agricultural biological control.
A salt-tolerant strain SF-18 with significant antibacterial activity was isolated and screened from soil samples in Aksu saline alkali land, Xinjiang. The SF-18 strain has a significant inhibitory effect on Staphylococcus aureus and Verticillium dahlia and could grow in the broth containing 18% NaCl. Using the Verticillium dahlia as an indicator strain, the SF-18 cell-free fermentation supernatant showed stable antibacterial activity within the range of -20℃-80℃, and pH 5-pH 12 environments. The strain was identified as belonging to the genus Bacillus based on the 16S rDNA gene and gyrB gene sequences. Whole gene sequence analysis showed that there were 480 genes of the strain involved in the metabolism of multiple carbon sources. The strain contained genes encoding the alimine and trehalose which are related to stress resistance. The prediction analysis of secondary metabolites showed that strain SF-18 contained gene clusters related to synthesize a various of resistant compounds, such as bacillaene, bacillibactin, mersacidin, fengycin, zwittermicin, as well as genes related to glucanase and chitinase that can hydrolyze the cell wall of pathogen. Therefore, it is speculated that strain SF-18 can produce antibacterial secondary metabolites and related degrading enzymes to prevent and control plant disease, showing good application prospects in agricultural biological control.
Abstract:
It is to screen microaerobic Fe2+ oxidizing bacteria (FeOB) with better oxidative abilities to Fe2+ and to evaluate its effects on improvement of gleyed paddy soils and soil microbial communities and functions, laying a foundation for establishing microbial improvement technologies of gleyed paddy fields. FeOB were enriched using Modified wolf’s mineral medium. The FeOB strain was taxonomically identified by combined technologies, including 16S rRNA sequencing, et al. Pot experiments were conducted to evaluate the effects of the strain on soil reducing substances, soil nutrients, nitrogen cycling functional gene (NCFG) abundances and rice seedlings in gleyed paddy soils. The impacts on the soil micro-ecology were examined using 16S rRNA high-throughput sequencing technology. As a result, a FeOB strain exhibiting a strong oxidative effect on Fe2+ was obtained and was subsequently identified as Lysinibacillus sphaericus WH07. The 100 mL fermentation liquids of the strain WH07 were used to treat gleyed paddy soil with different concentration of 106 (T1), 107 (T2), 108 (T3) CFU/mL, respectively. Compared to the control, the soil redox potentials (Eh) were significantly increased (P<0.05), being changed from negative to positive potentials. The total reducing substances, the ferrous contents, and the manganese contents, all were decreased by 0.37%?53.19% in all three treatments and were significantly decreased in both T2 and T3 (P<0.05). Five routine indicators of the soils, including the alkaline hydrolyzed nitrogen contents, et al., were all significantly increased by 3.40%?49.90% (P<0.05). Four NCFG, including AOA-amoA, et al., were increased or significantly increased in abundance compared with the control. The physiological indicators of rice seedlings, including plant heights, et al., were higher or significantly higher than the control. Both Chao1 and Shannon α diversity indexes were significantly decreased than the control (P<0.05). Among top 10 phyla of soil bacteria, 8 phyla were significantly down-regulated, including Proteobacteria, et al., while 2 phyla (Bacteroidetes and Firmicutes) were significantly up-regulated. Among top 50 genera, a total of 20, 19, and 22 genera were significantly up-regulated respectively in three treatments (P<0.05), including 6 FeOB, such as Macellibacteroides, et al., while 25 genera were significantly down-regulated in all three treatments (P<0.05), composing of 4 Fe reducing bacteria, such as MBNT15, et al. Analysis of the regulating network showed that the strain WH07 potentially coordinated with other FeOB improved soil physiochemical properties and biological activities, finally improving the growth of rice seedlings. The results of this study showed that application of the strain WH07 significantly improved the physiochemical properties of the gleyed rice soil and significantly changed soil microbial communities and functions, laying a foundation for research and development of highly efficient microbial agents improving gleyed paddy soils.
It is to screen microaerobic Fe2+ oxidizing bacteria (FeOB) with better oxidative abilities to Fe2+ and to evaluate its effects on improvement of gleyed paddy soils and soil microbial communities and functions, laying a foundation for establishing microbial improvement technologies of gleyed paddy fields. FeOB were enriched using Modified wolf’s mineral medium. The FeOB strain was taxonomically identified by combined technologies, including 16S rRNA sequencing, et al. Pot experiments were conducted to evaluate the effects of the strain on soil reducing substances, soil nutrients, nitrogen cycling functional gene (NCFG) abundances and rice seedlings in gleyed paddy soils. The impacts on the soil micro-ecology were examined using 16S rRNA high-throughput sequencing technology. As a result, a FeOB strain exhibiting a strong oxidative effect on Fe2+ was obtained and was subsequently identified as Lysinibacillus sphaericus WH07. The 100 mL fermentation liquids of the strain WH07 were used to treat gleyed paddy soil with different concentration of 106 (T1), 107 (T2), 108 (T3) CFU/mL, respectively. Compared to the control, the soil redox potentials (Eh) were significantly increased (P<0.05), being changed from negative to positive potentials. The total reducing substances, the ferrous contents, and the manganese contents, all were decreased by 0.37%?53.19% in all three treatments and were significantly decreased in both T2 and T3 (P<0.05). Five routine indicators of the soils, including the alkaline hydrolyzed nitrogen contents, et al., were all significantly increased by 3.40%?49.90% (P<0.05). Four NCFG, including AOA-amoA, et al., were increased or significantly increased in abundance compared with the control. The physiological indicators of rice seedlings, including plant heights, et al., were higher or significantly higher than the control. Both Chao1 and Shannon α diversity indexes were significantly decreased than the control (P<0.05). Among top 10 phyla of soil bacteria, 8 phyla were significantly down-regulated, including Proteobacteria, et al., while 2 phyla (Bacteroidetes and Firmicutes) were significantly up-regulated. Among top 50 genera, a total of 20, 19, and 22 genera were significantly up-regulated respectively in three treatments (P<0.05), including 6 FeOB, such as Macellibacteroides, et al., while 25 genera were significantly down-regulated in all three treatments (P<0.05), composing of 4 Fe reducing bacteria, such as MBNT15, et al. Analysis of the regulating network showed that the strain WH07 potentially coordinated with other FeOB improved soil physiochemical properties and biological activities, finally improving the growth of rice seedlings. The results of this study showed that application of the strain WH07 significantly improved the physiochemical properties of the gleyed rice soil and significantly changed soil microbial communities and functions, laying a foundation for research and development of highly efficient microbial agents improving gleyed paddy soils.
Abstract:
Withering is an important process of black tea processing, in order to explore the effect of solar withering on the quality of black tea prepared from different fresh leaf tenderness and tea plant cultivars, solar withering experiments were carried out on different varieties such as black tea varieties, green tea varieties, red and green varieties, as well as fresh leaves with different tenderness, such as one bud of one leaf, one bud of two leaves. The results showed that the effects of sun withering on the quality of black tea of different fresh leaf tenderness and tea plant cultivars were compared in this research. The results showed that the effects of sun withering on the quality of black tea of different fresh leaf tenderness and tea plant cultivars were different. The raw materials with the tender degree of one bud of two and three leaves and below were suitabled for sun withering, and the leaf damage was less during the withering process, the content of tea polyphenols and amino acids decreased less, and the content of soluble sugar increased more, increasing by 15%, 13% and 11%, and the content of theaflavins was higher, among which theaflavins in black tea with three leaves and four or five leaves of one bud increased significantly (32% and 10%). Research has shown that sun withering was more suitable for tea plant varieties with weak flowery and fruity aroma, and it was not necessary to carry out sun withering for varieties with rich flowery and fruity aroma, while the albino and purple varieties were not suitable for sun withering.
Withering is an important process of black tea processing, in order to explore the effect of solar withering on the quality of black tea prepared from different fresh leaf tenderness and tea plant cultivars, solar withering experiments were carried out on different varieties such as black tea varieties, green tea varieties, red and green varieties, as well as fresh leaves with different tenderness, such as one bud of one leaf, one bud of two leaves. The results showed that the effects of sun withering on the quality of black tea of different fresh leaf tenderness and tea plant cultivars were compared in this research. The results showed that the effects of sun withering on the quality of black tea of different fresh leaf tenderness and tea plant cultivars were different. The raw materials with the tender degree of one bud of two and three leaves and below were suitabled for sun withering, and the leaf damage was less during the withering process, the content of tea polyphenols and amino acids decreased less, and the content of soluble sugar increased more, increasing by 15%, 13% and 11%, and the content of theaflavins was higher, among which theaflavins in black tea with three leaves and four or five leaves of one bud increased significantly (32% and 10%). Research has shown that sun withering was more suitable for tea plant varieties with weak flowery and fruity aroma, and it was not necessary to carry out sun withering for varieties with rich flowery and fruity aroma, while the albino and purple varieties were not suitable for sun withering.
Abstract:
Under the condition of greenhouse, the pot culture method of vermiculite mixed soil was used to explore the effects of single inoculation and double inoculation of rhizobium and arbuscular mycorrhizal fungi on the growth of 10 different strains of soybean planted in most regions of China. The results showed that both rhizobium Bradyrhizobium japonicum USDA110 and mycorrhizal fungus Rhizophagus irregularis could colonize all tested soybean strains and form symbiotic structure. Inoculation of rhizobium and mycorrhizal fungi alone could significantly increase the aboveground fresh weight of soybean, in which inoculation of rhizobium alone could increase the aboveground fresh weight of soybean strains 119, 851 and 921 by 102% - 429%. Inoculation of mycorrhizal fungi alone could also increase the aboveground fresh weight of most strains of soybean by 39% - 255%. Under the condition of double inoculation of rhizobium and mycorrhizal fungi, the symbiosis of mycorrhizal fungi showed the phenomenon of symbiotic colonization delay. In the presence of mycorrhizal fungi, the single nodule volume and nitrogenase activity of soybean lines 985, 851 and 115 increased. Therefore, the same inoculation method has different effects on different strains of soybean, and the growth of the same strain soybean is also different after different inoculation methods. The double inoculation method was the best for 985 and 115 lines, the single inoculation of rhizobium for 851, 167, 509, 921 and 168 was the best, and 119, 909 and 045 could be inoculated with rhizobium or mycorrhizal fungi to increase the yield.
Under the condition of greenhouse, the pot culture method of vermiculite mixed soil was used to explore the effects of single inoculation and double inoculation of rhizobium and arbuscular mycorrhizal fungi on the growth of 10 different strains of soybean planted in most regions of China. The results showed that both rhizobium Bradyrhizobium japonicum USDA110 and mycorrhizal fungus Rhizophagus irregularis could colonize all tested soybean strains and form symbiotic structure. Inoculation of rhizobium and mycorrhizal fungi alone could significantly increase the aboveground fresh weight of soybean, in which inoculation of rhizobium alone could increase the aboveground fresh weight of soybean strains 119, 851 and 921 by 102% - 429%. Inoculation of mycorrhizal fungi alone could also increase the aboveground fresh weight of most strains of soybean by 39% - 255%. Under the condition of double inoculation of rhizobium and mycorrhizal fungi, the symbiosis of mycorrhizal fungi showed the phenomenon of symbiotic colonization delay. In the presence of mycorrhizal fungi, the single nodule volume and nitrogenase activity of soybean lines 985, 851 and 115 increased. Therefore, the same inoculation method has different effects on different strains of soybean, and the growth of the same strain soybean is also different after different inoculation methods. The double inoculation method was the best for 985 and 115 lines, the single inoculation of rhizobium for 851, 167, 509, 921 and 168 was the best, and 119, 909 and 045 could be inoculated with rhizobium or mycorrhizal fungi to increase the yield.
Abstract:
Industrial syngas contains a large amount of CO2, and the resource utilization of CO2 is of great significance to the current environmental improvement. The homoacetogenesis in the anaerobic fermentation process has two characteristics : autotrophic and heterotrophic. It can use CO2 and H2 to produce acetic acid, and can also degrade glucose to produce volatile fatty acids ( VFAs ). This study intends to use its autotrophic characteristics to explore its ability to convert CO2 into resources, and to explore the effects of headspace H2 / CO2 ratio, carbon source type and pH value on the synthesis of homoacetogenesis reaction products. The results showed that high pH value was conducive to the autotrophic reaction of homoacetogenic bacteria using H2 / CO2 mixed gas. When pH = 5 and H2 / CO2 = 3 : 1, the yield of VFAs ( including acetic acid, propionic acid and butyric acid ) was the highest, reaching 3369.89 mg / L, and the proportion of acetic acid was 76.1 %. When glucose and H2 / CO2 mixed gas were used as a common carbon source, the homoacetogenic bacteria would preferentially use glucose for heterotrophic reaction, and then the H2 / CO2 mixed gas began to be utilized.Significant analysis showed that there was a weak correlation between VFAs content and pH value, but a negative correlation with H2 / CO2, indicating that CO2 content had a greater impact on the autotrophic pathway of homoacetogens. In addition, this paper also established a BP neural network prediction model for homoacetogenic reaction, which can accurately predict the VFAs production of homoacetogenic bacteria with H2 / CO2 mixed gas as carbon source ( R2 = 0.96584 ).
Industrial syngas contains a large amount of CO2, and the resource utilization of CO2 is of great significance to the current environmental improvement. The homoacetogenesis in the anaerobic fermentation process has two characteristics : autotrophic and heterotrophic. It can use CO2 and H2 to produce acetic acid, and can also degrade glucose to produce volatile fatty acids ( VFAs ). This study intends to use its autotrophic characteristics to explore its ability to convert CO2 into resources, and to explore the effects of headspace H2 / CO2 ratio, carbon source type and pH value on the synthesis of homoacetogenesis reaction products. The results showed that high pH value was conducive to the autotrophic reaction of homoacetogenic bacteria using H2 / CO2 mixed gas. When pH = 5 and H2 / CO2 = 3 : 1, the yield of VFAs ( including acetic acid, propionic acid and butyric acid ) was the highest, reaching 3369.89 mg / L, and the proportion of acetic acid was 76.1 %. When glucose and H2 / CO2 mixed gas were used as a common carbon source, the homoacetogenic bacteria would preferentially use glucose for heterotrophic reaction, and then the H2 / CO2 mixed gas began to be utilized.Significant analysis showed that there was a weak correlation between VFAs content and pH value, but a negative correlation with H2 / CO2, indicating that CO2 content had a greater impact on the autotrophic pathway of homoacetogens. In addition, this paper also established a BP neural network prediction model for homoacetogenic reaction, which can accurately predict the VFAs production of homoacetogenic bacteria with H2 / CO2 mixed gas as carbon source ( R2 = 0.96584 ).
Abstract:
In order to establish a rapid method for the determination of lutein content in the petals of marigold (Tagetes erecta), the values of L* (brightness), a* (redness) and b* (yellowness) of marigold petals were measured by colorimeter and the color factors, such as a*/b*, (a*/b*)2, chroma, hue and shade were calculated. At the same time, UV- Spectrophotometry combined with HPLC method was used to determine the lutein content of petals, and the correlation between lutein content and these color factors was analyzed, and the regression equation was established and verified. The results showed that the lutein content of marigold petals was significantly correlated with a*、a*/b*、(a*/b*)2, hue and shade; the regression equation between lutein content and a* value constructed by cubic function model had the highest degree of fit, and there was no significant difference between the predicted value and the measured value of lutein content. The results showed that the cubic function model based on a* value could quickly and non-destructively predict the lutein content of marigold petals.
In order to establish a rapid method for the determination of lutein content in the petals of marigold (Tagetes erecta), the values of L* (brightness), a* (redness) and b* (yellowness) of marigold petals were measured by colorimeter and the color factors, such as a*/b*, (a*/b*)2, chroma, hue and shade were calculated. At the same time, UV- Spectrophotometry combined with HPLC method was used to determine the lutein content of petals, and the correlation between lutein content and these color factors was analyzed, and the regression equation was established and verified. The results showed that the lutein content of marigold petals was significantly correlated with a*、a*/b*、(a*/b*)2, hue and shade; the regression equation between lutein content and a* value constructed by cubic function model had the highest degree of fit, and there was no significant difference between the predicted value and the measured value of lutein content. The results showed that the cubic function model based on a* value could quickly and non-destructively predict the lutein content of marigold petals.
Abstract:
Silver ion (Ag+) poses serious threat to the environment and human health, therefore, accurate and interference-free detection of Ag+ is of great scientific significance and practical application value. To achieve this purpose, the surface-enhanced Raman spectroscopy (SERS) sensing detection technology based on functionalized gold nanoparticles was established, when Ag+ were present, based on the coordination of Ag+ and cyanogroup (-CN) in merhydryl benzonitrile (MBN) modified on the surface of gold nanoparticles, the gold nanoparticles were controlled to gather, forming a chain structure and generating the "hot spot" effect, the SERS signal of MBN was enhanced at 2228 cm-1 in the biological "silent zone", and the degree of enhancement increased with the increase of Ag+ concentration. The results show that, in the concentration interval of 0.1 nM ~ 100 nM, the linear relationship is good, and the minimum detectable concentration of Ag+ is 0.1 nM, which is far lower than the Environmental Protection Agency (EPA) regulation that the concentration of Ag+ in drinking water which should be less than 0.93 μM. While the recovery rate of Ag+ was 99.7% ~ 101.4% in actual water samples.
Silver ion (Ag+) poses serious threat to the environment and human health, therefore, accurate and interference-free detection of Ag+ is of great scientific significance and practical application value. To achieve this purpose, the surface-enhanced Raman spectroscopy (SERS) sensing detection technology based on functionalized gold nanoparticles was established, when Ag+ were present, based on the coordination of Ag+ and cyanogroup (-CN) in merhydryl benzonitrile (MBN) modified on the surface of gold nanoparticles, the gold nanoparticles were controlled to gather, forming a chain structure and generating the "hot spot" effect, the SERS signal of MBN was enhanced at 2228 cm-1 in the biological "silent zone", and the degree of enhancement increased with the increase of Ag+ concentration. The results show that, in the concentration interval of 0.1 nM ~ 100 nM, the linear relationship is good, and the minimum detectable concentration of Ag+ is 0.1 nM, which is far lower than the Environmental Protection Agency (EPA) regulation that the concentration of Ag+ in drinking water which should be less than 0.93 μM. While the recovery rate of Ag+ was 99.7% ~ 101.4% in actual water samples.
Abstract:
Abstract: In order to study the effect of different pretreatment methods of sugar removal on the quality of red jujube crisp slices dried by hot air drying and pressure difference flash drying. Ultrasound (US), ultrasound-assisted enzymatic method (US+EM), ultrasound-assisted alkaline method (Ultrasound-assisted alkaline method) were performed on the red date crisp tablets. After US+AM) and Ultrasound assisted hot-water method (US+WM), the color, texture (hardness, brittleness), taste and main nutrients (polysaccharide, flavone, VC) of dried jujube crisp were determined and analyzed. After ultrasonic assisted desugaration, the US+EM treatment group had the lowest water loss rate, the reduction rate of solid matter was 3.36%, and the polysaccharide content of jujube crisp chips was decreased, among which the US+WM treatment group had the lowest pressure difference flash dry jujube crisp chips content, which was 12.11 mg/100 g. The loss of flavonol content, antioxidant capacity and VC content in US+EM treatment group was the smallest, and there were significant differences among different treatment groups (P < 0.05). In addition, the electronic tongue results showed that US+EM treatment had the best taste for flash dried red date crisp. Based on the above research results, the ultrasound-assisted enzymatic treatment can minimize the quality of jujube chips and reduce the sugar, so as to meet modern people's pursuit of natural, nutritious and healthy leisure food.
Abstract: In order to study the effect of different pretreatment methods of sugar removal on the quality of red jujube crisp slices dried by hot air drying and pressure difference flash drying. Ultrasound (US), ultrasound-assisted enzymatic method (US+EM), ultrasound-assisted alkaline method (Ultrasound-assisted alkaline method) were performed on the red date crisp tablets. After US+AM) and Ultrasound assisted hot-water method (US+WM), the color, texture (hardness, brittleness), taste and main nutrients (polysaccharide, flavone, VC) of dried jujube crisp were determined and analyzed. After ultrasonic assisted desugaration, the US+EM treatment group had the lowest water loss rate, the reduction rate of solid matter was 3.36%, and the polysaccharide content of jujube crisp chips was decreased, among which the US+WM treatment group had the lowest pressure difference flash dry jujube crisp chips content, which was 12.11 mg/100 g. The loss of flavonol content, antioxidant capacity and VC content in US+EM treatment group was the smallest, and there were significant differences among different treatment groups (P < 0.05). In addition, the electronic tongue results showed that US+EM treatment had the best taste for flash dried red date crisp. Based on the above research results, the ultrasound-assisted enzymatic treatment can minimize the quality of jujube chips and reduce the sugar, so as to meet modern people's pursuit of natural, nutritious and healthy leisure food.
Abstract:
Rapeseed is the second largest oil crop in the world, and also the most important source of edible vegetable oil in China. For a long time, rapeseed breeders have tried to breed superior varieties through traditional breeding strategies. However, Brassica napus is an allotetraploid species evolved from double diploidization after interspecific hybridization, and there are many gene redundancy in its genome. Therefore, the efficiency of improving traits through traditional genetic methods such as artificial hybridization selection and random mutagenesis is very low. To achieve rapid and efficient innovation of germplasm resources and genetic improvement in rapeseed, the application of CRISPR/Cas9 gene editing technology is not only appropriate but also timely for rapeseed. In recent years, CRISPR/Cas9 technology has been widely used in gene function research and targeted genetic improvement of polyploid rapeseed due to its unique advantages of high efficiency and simplicity. The present article reviews the current researches on the application of CRISPR/Cas9 system in the study of gene function and genetic improvement of rapeseed, involving important agronomic traits such as yield, oil content and fatty acid composition, biological and abiotic stress tolerance. The limitations of gene editing in rapeseed and the direction of its future development were also discussed.
Rapeseed is the second largest oil crop in the world, and also the most important source of edible vegetable oil in China. For a long time, rapeseed breeders have tried to breed superior varieties through traditional breeding strategies. However, Brassica napus is an allotetraploid species evolved from double diploidization after interspecific hybridization, and there are many gene redundancy in its genome. Therefore, the efficiency of improving traits through traditional genetic methods such as artificial hybridization selection and random mutagenesis is very low. To achieve rapid and efficient innovation of germplasm resources and genetic improvement in rapeseed, the application of CRISPR/Cas9 gene editing technology is not only appropriate but also timely for rapeseed. In recent years, CRISPR/Cas9 technology has been widely used in gene function research and targeted genetic improvement of polyploid rapeseed due to its unique advantages of high efficiency and simplicity. The present article reviews the current researches on the application of CRISPR/Cas9 system in the study of gene function and genetic improvement of rapeseed, involving important agronomic traits such as yield, oil content and fatty acid composition, biological and abiotic stress tolerance. The limitations of gene editing in rapeseed and the direction of its future development were also discussed.
Abstract:
To investigate the function of the GmSBT1 gene in nitrogen fixation in symbiosis between rhizobia and host plants, bioinformatics analysis, spatiotemporal expression localization, GUS staining localization and gene silencing were used to investigate its role in soybean rhizobia symbiosis. The results showed that the gene was specifically induced by rhizobia and only expressed at high levels in the rhizobia, possibly in the rhizobia cortex and bacterial cells. RNAi interference significantly reduced the aboveground fresh weight, nodule weight, and nitrogenase activity. This indicates that the GmSBT1 protein plays an important role in the formation and development of nodules, as well as nitrogen fixation in nodules.
To investigate the function of the GmSBT1 gene in nitrogen fixation in symbiosis between rhizobia and host plants, bioinformatics analysis, spatiotemporal expression localization, GUS staining localization and gene silencing were used to investigate its role in soybean rhizobia symbiosis. The results showed that the gene was specifically induced by rhizobia and only expressed at high levels in the rhizobia, possibly in the rhizobia cortex and bacterial cells. RNAi interference significantly reduced the aboveground fresh weight, nodule weight, and nitrogenase activity. This indicates that the GmSBT1 protein plays an important role in the formation and development of nodules, as well as nitrogen fixation in nodules.
Abstract:
In order to solve the problem that rapeseed grains are easily broken in the process of shredding and throwing in a self-developed rapeseed combine, the discrete element simulation of kernel crushing and the optimization of the shredding and throwing device were carried out. Based on the discrete element method, the rapeseed kernel bonding model was constructed and uniaxial compression test was carried out. According to the steepest climb test and Box-Behnken test, the optimal parameter combination of rape kernel bonding model is 7.0×109N/m, 6.82×109N/m, 6.61×1010Pa, 8.18×1010Pa, when the normal stiffness coefficient, tangential stiffness coefficient, critical normal stress and critical tangential stress are respectively. The simulation value of rapeseed grain crushing load was 12.67N, and the relative error with the physical value was 3.59%. Combined with the rapeseed grain bonding model, a simulation model of the shredding and throwing device of the rapeseed combine harvester was established. The three-factor and three-level Box-Behnken test was carried out with the rotating speed of the drum, the shredding clearance and the number of cutters as test factors, and the optimal parameter combination of the shredding and throwing device was determined. The results showed that: The optimal parameter combination of the shredding and throwing device is the drum speed 450r/min, the shredding clearance 30mm and the number of cutting tools 10. Bench test and field test of the rapeseed shredding and throwing device were carried out. The bench test results showed that with the increase of the rotation speed of the shredding drum, the rapeseed kernel crushing rate of the shredding and throwing device showed a linear increase trend. Field experiment results showed that the average rate of rapeseed grain breakage was 0.82%, and the operation of the shredding and throwing device was smooth. This study can provide a reference for the improvement and optimization of the structure of the cutting and throwing device for rape combined harvest.
In order to solve the problem that rapeseed grains are easily broken in the process of shredding and throwing in a self-developed rapeseed combine, the discrete element simulation of kernel crushing and the optimization of the shredding and throwing device were carried out. Based on the discrete element method, the rapeseed kernel bonding model was constructed and uniaxial compression test was carried out. According to the steepest climb test and Box-Behnken test, the optimal parameter combination of rape kernel bonding model is 7.0×109N/m, 6.82×109N/m, 6.61×1010Pa, 8.18×1010Pa, when the normal stiffness coefficient, tangential stiffness coefficient, critical normal stress and critical tangential stress are respectively. The simulation value of rapeseed grain crushing load was 12.67N, and the relative error with the physical value was 3.59%. Combined with the rapeseed grain bonding model, a simulation model of the shredding and throwing device of the rapeseed combine harvester was established. The three-factor and three-level Box-Behnken test was carried out with the rotating speed of the drum, the shredding clearance and the number of cutters as test factors, and the optimal parameter combination of the shredding and throwing device was determined. The results showed that: The optimal parameter combination of the shredding and throwing device is the drum speed 450r/min, the shredding clearance 30mm and the number of cutting tools 10. Bench test and field test of the rapeseed shredding and throwing device were carried out. The bench test results showed that with the increase of the rotation speed of the shredding drum, the rapeseed kernel crushing rate of the shredding and throwing device showed a linear increase trend. Field experiment results showed that the average rate of rapeseed grain breakage was 0.82%, and the operation of the shredding and throwing device was smooth. This study can provide a reference for the improvement and optimization of the structure of the cutting and throwing device for rape combined harvest.
liuchenglang, huangwenkai, yansuyun, zhouxianyan, dongmeichao, xuxiangzeng, gaoshide, gaojunyan, dengxiuxin, chailijun
Abstract:
Fruit seedlessness is a major excellent agronomic trait of citrus, in order to clarify the cause of seedlessness of ‘Dongshi Zaoyou’ pummelo. Taking ‘Dongshi Zaoyou’ pummelo and its hybrid offspring as the main test materials, we explored the causes of seedlessness of ‘Dongshi Zaoyou’ pummelo by using the staining methods of magenta acetate and aniline blue, cross-pollination and molecular markers. The results showed that ‘Dongshi Zaoyou’ pummelo was observed to have complete floral structures, pollen viability and pollen germination rates of 94.80% and 86.62%, respectively. ‘Dongshi Zaoyou’ pummelo showed self-incompatibility, whereas crosses with ‘Shatianyou’ pummelo showed cross-compatibility. A total of 164 F1 hybrids were identified from 175 cross progenies of ‘Shatianyou’ pummelo × ‘Dongshi Zaoyou’ pummelo using S5/S6-genotyped molecular markers, which excluded the possibility of male sterility in ‘Dongshi Zaoyou’ pummelo. In addition, the fruit set percentage of ‘Dongshi Zaoyou’ pummelo was 13.04% and 25.56% for two consecutive years with stimulating parthenocarpy and natural parthenocarpy, respectively. It was inferred that the self-incompatibility of ‘Dongshi Zaoyou’ pummelo and its ability to produce a partial parthenocarpy were the main reasons for its seedlessness.
Fruit seedlessness is a major excellent agronomic trait of citrus, in order to clarify the cause of seedlessness of ‘Dongshi Zaoyou’ pummelo. Taking ‘Dongshi Zaoyou’ pummelo and its hybrid offspring as the main test materials, we explored the causes of seedlessness of ‘Dongshi Zaoyou’ pummelo by using the staining methods of magenta acetate and aniline blue, cross-pollination and molecular markers. The results showed that ‘Dongshi Zaoyou’ pummelo was observed to have complete floral structures, pollen viability and pollen germination rates of 94.80% and 86.62%, respectively. ‘Dongshi Zaoyou’ pummelo showed self-incompatibility, whereas crosses with ‘Shatianyou’ pummelo showed cross-compatibility. A total of 164 F1 hybrids were identified from 175 cross progenies of ‘Shatianyou’ pummelo × ‘Dongshi Zaoyou’ pummelo using S5/S6-genotyped molecular markers, which excluded the possibility of male sterility in ‘Dongshi Zaoyou’ pummelo. In addition, the fruit set percentage of ‘Dongshi Zaoyou’ pummelo was 13.04% and 25.56% for two consecutive years with stimulating parthenocarpy and natural parthenocarpy, respectively. It was inferred that the self-incompatibility of ‘Dongshi Zaoyou’ pummelo and its ability to produce a partial parthenocarpy were the main reasons for its seedlessness.
Abstract:
Aiming at the problems such as complex tea garden background, different scale of tea diseases, minimal disease spots and easy to miss and misdetect, an improved Faster RCNN model was proposed to identify tea leaf diseases.By comparing the feature extraction network VGG-16, mobilenetv2 and ResNet50 with optimized region suggestion frame, ResNet50 is selected as the backbone network with good effect;FPN network is integrated to improve the problem of missing detection of small targets and multi-scale problem of disease spots;Rank & Sort (RS) Loss function is used to replace the loss function in the original Faster RCNN to alleviate the impact of uneven sample distribution on model performance.The results show: The average precision mAP of the model proposed in this study was 88.06%, the detection speed was 19.1 frames /s, and the average accuracy of the identification of algal spot, white star disease, anthrax and soot disease was 75.54%, 86.84%, 90.42% and 99.45%, respectively. Compared with the original Faster RCNN model, the improvements were 40.98%, 44.16%, 13.9% and 2.43%, respectively.The results showed that this study could well detect and identify tea leaf diseases under the complex background of tea gardens, meet the requirements of tea leaf disease detection, provide reference for tea disease detection under natural environment, and have important research significance for tea disease prevention.
Aiming at the problems such as complex tea garden background, different scale of tea diseases, minimal disease spots and easy to miss and misdetect, an improved Faster RCNN model was proposed to identify tea leaf diseases.By comparing the feature extraction network VGG-16, mobilenetv2 and ResNet50 with optimized region suggestion frame, ResNet50 is selected as the backbone network with good effect;FPN network is integrated to improve the problem of missing detection of small targets and multi-scale problem of disease spots;Rank & Sort (RS) Loss function is used to replace the loss function in the original Faster RCNN to alleviate the impact of uneven sample distribution on model performance.The results show: The average precision mAP of the model proposed in this study was 88.06%, the detection speed was 19.1 frames /s, and the average accuracy of the identification of algal spot, white star disease, anthrax and soot disease was 75.54%, 86.84%, 90.42% and 99.45%, respectively. Compared with the original Faster RCNN model, the improvements were 40.98%, 44.16%, 13.9% and 2.43%, respectively.The results showed that this study could well detect and identify tea leaf diseases under the complex background of tea gardens, meet the requirements of tea leaf disease detection, provide reference for tea disease detection under natural environment, and have important research significance for tea disease prevention.
Abstract:
Glyphosate and glufosinate are two widely used non-selective herbicides globally. The former inhibits the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) in the plant's shikimate acid metabolic pathway, while the latter inhibits the glutamine synthetase (GS) essential for plant ammonia assimilation. Both herbicides can non-selectively kill annual plants, including crops. The introduction of glyphosate-resistant genes into crops confers herbicide tolerance (HT) to the crops, which holds significant value in the field of molecular breeding. This study isolated a halophilic bacterium (Halomonas sp.) with high resistance to glyphosate from marine bacteria. Through genome sequencing and bioinformatic analysis, the coding gene (fHoEPSPS) for 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) in this strain was identified to encode a bifunctional enzyme (fHoEPSPS) fused with a prephenate dehydratase (PDT) domain. The full-length fHoEPSPS, the G384A mutant (mfHoEPSPS), and a mutant lacking the N-terminal PDT domain (mHoEPSPS) were recombinantly expressed and purified in E. coli (DE3). Glyphosate resistance analysis revealed that the resistance of mfHoEPSPS was 19 times higher than that of fHoEPSPS. The introduction of the mHoEPSPS coding gene into tobacco confers a 3 times the recommended dosage of glyphosate tolerance. Moreover, to develop enzyme with both glyphosate and glufosinate tolerance, we constructd a chimeric enzyme by linking the glufosinate -resistant enzyme (Repat) at the N-terminus of mHoEPSPS with the self-cleaving peptide LP4/2A, resulting RLH. Tobacco transformed with the RLH gene exhibited simultaneous tolerance to 3-5 times the recommended dosage of glyphosate/glufosinate compound herbicides. This research provides new genetic resources for the breeding of HT crops and provide us new insights into the cultivation of dual-resistant glyphosate/glufosinate crops to address the evolution of glyphosate-resistant weeds.
Glyphosate and glufosinate are two widely used non-selective herbicides globally. The former inhibits the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) in the plant's shikimate acid metabolic pathway, while the latter inhibits the glutamine synthetase (GS) essential for plant ammonia assimilation. Both herbicides can non-selectively kill annual plants, including crops. The introduction of glyphosate-resistant genes into crops confers herbicide tolerance (HT) to the crops, which holds significant value in the field of molecular breeding. This study isolated a halophilic bacterium (Halomonas sp.) with high resistance to glyphosate from marine bacteria. Through genome sequencing and bioinformatic analysis, the coding gene (fHoEPSPS) for 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) in this strain was identified to encode a bifunctional enzyme (fHoEPSPS) fused with a prephenate dehydratase (PDT) domain. The full-length fHoEPSPS, the G384A mutant (mfHoEPSPS), and a mutant lacking the N-terminal PDT domain (mHoEPSPS) were recombinantly expressed and purified in E. coli (DE3). Glyphosate resistance analysis revealed that the resistance of mfHoEPSPS was 19 times higher than that of fHoEPSPS. The introduction of the mHoEPSPS coding gene into tobacco confers a 3 times the recommended dosage of glyphosate tolerance. Moreover, to develop enzyme with both glyphosate and glufosinate tolerance, we constructd a chimeric enzyme by linking the glufosinate -resistant enzyme (Repat) at the N-terminus of mHoEPSPS with the self-cleaving peptide LP4/2A, resulting RLH. Tobacco transformed with the RLH gene exhibited simultaneous tolerance to 3-5 times the recommended dosage of glyphosate/glufosinate compound herbicides. This research provides new genetic resources for the breeding of HT crops and provide us new insights into the cultivation of dual-resistant glyphosate/glufosinate crops to address the evolution of glyphosate-resistant weeds.
Abstract:
To enhance the accuracy of mechanical harvesting of pineapples in regions with different maturity levels and ensure the quality of pineapples, a real-time pineapple ripeness detection method based on improved YOLOv8 is proposed. Addressing challenges such as small and densely packed targets and light obstruction in natural environments, this study replaces the common convolutions in the backbone and neck parts of the original YOLOv8 model with Depthwise Separable Convolutions (DSConv) to streamline model parameters. Additionally, a Convolutional Block Attention Module (CBAM) is introduced before feature fusion to prioritize important features, thereby improving the accuracy of target detection. The YOLOv8 network's original loss function, CIoU, is replaced with the EIoU loss function to expedite network convergence.Various ablation experiments are designed for different modules in the study, demonstrating the effectiveness of each improvement. The results show that the PmA of the improved model for pineapple maturity detection is 97.33%, which is 5.53, 7.91, 4.38 and 4.66 percentage points higher than that of Faster R-CNN, YOLOv4, YOLOv5 and YOLOv7, respectively. On the premise of ensuring the detection accuracy, the number of model parameters of the algorithm is only 16.8×106. The results show that the improved model improves the accuracy and inference speed of pineapple maturity recognition, and has stronger robustness.
To enhance the accuracy of mechanical harvesting of pineapples in regions with different maturity levels and ensure the quality of pineapples, a real-time pineapple ripeness detection method based on improved YOLOv8 is proposed. Addressing challenges such as small and densely packed targets and light obstruction in natural environments, this study replaces the common convolutions in the backbone and neck parts of the original YOLOv8 model with Depthwise Separable Convolutions (DSConv) to streamline model parameters. Additionally, a Convolutional Block Attention Module (CBAM) is introduced before feature fusion to prioritize important features, thereby improving the accuracy of target detection. The YOLOv8 network's original loss function, CIoU, is replaced with the EIoU loss function to expedite network convergence.Various ablation experiments are designed for different modules in the study, demonstrating the effectiveness of each improvement. The results show that the PmA of the improved model for pineapple maturity detection is 97.33%, which is 5.53, 7.91, 4.38 and 4.66 percentage points higher than that of Faster R-CNN, YOLOv4, YOLOv5 and YOLOv7, respectively. On the premise of ensuring the detection accuracy, the number of model parameters of the algorithm is only 16.8×106. The results show that the improved model improves the accuracy and inference speed of pineapple maturity recognition, and has stronger robustness.
Abstract:
Aiming at the problem that the existing chain-type paper pot seedling transplanters are mostly continuous chain transplanting with unadjustable plant spacing and cannot meet the requirements of large plant spacing crop transplanting, this paper explored and designed a seedling chain breaking device for chain pot seedling transplanters, taking conventional hexagonal cross-section chain pot seedlings as the test object. Based on the principle of seedling chain breaking device, the structure of key components and the value range of working parameters were determined through theoretical analysis of working process. A test bench was set up for single factor test, with the opening of the pinch finger, the inclination angle of the seedling chute and the planting frequency as the main test factors, and the success rate of seedling taking and the matrix loss rate as the evaluation indexes. The orthogonal combination test of three factors and three levels was carried out to analyze the influence of each factor on the evaluation index and optimize it. The test results showed that the effect was better when the opening of the pinch finger was 52mm, the inclination angle of the seedling chute was 20°, and the planting frequency was 45 plants/min. Under this parameter combination, the success rate of seedling taking was 91.3% and the matrix loss rate was 14.2% in the bench test, and the success rate of seedling taking was 87.5% and the matrix loss rate was 17.4% in the soil tank verification test. This study can provide reference for the development of the whole chain pot seedling transplanter.
Aiming at the problem that the existing chain-type paper pot seedling transplanters are mostly continuous chain transplanting with unadjustable plant spacing and cannot meet the requirements of large plant spacing crop transplanting, this paper explored and designed a seedling chain breaking device for chain pot seedling transplanters, taking conventional hexagonal cross-section chain pot seedlings as the test object. Based on the principle of seedling chain breaking device, the structure of key components and the value range of working parameters were determined through theoretical analysis of working process. A test bench was set up for single factor test, with the opening of the pinch finger, the inclination angle of the seedling chute and the planting frequency as the main test factors, and the success rate of seedling taking and the matrix loss rate as the evaluation indexes. The orthogonal combination test of three factors and three levels was carried out to analyze the influence of each factor on the evaluation index and optimize it. The test results showed that the effect was better when the opening of the pinch finger was 52mm, the inclination angle of the seedling chute was 20°, and the planting frequency was 45 plants/min. Under this parameter combination, the success rate of seedling taking was 91.3% and the matrix loss rate was 14.2% in the bench test, and the success rate of seedling taking was 87.5% and the matrix loss rate was 17.4% in the soil tank verification test. This study can provide reference for the development of the whole chain pot seedling transplanter.
Abstract:
In the face of resource shortage and increasing carbon emissions, how to change the traditional development model and promote the green transformation of the whole society is an important issue to be solved urgently in China to adhere to the green, low-carbon and circular development path. Based on the panel data of 30 provinces in China from 2010 to 2020, this paper constructs an index system and uses the entropy weight TOPSIS model, coupling coordination degree model and spatial autocorrelation model to analyze the coupling coordination degree of digital economy, low-carbon development and new urbanization and its spatio-temporal evolution characteristics. The results show that: (1) From 2010 to 2020, the comprehensive development level of the three systems has significantly improved, showing the spatial distribution characteristics of "high in the east and low in the west"; (2) The coupling coordination degree of the three systems showed a fluctuating upward trend, and the overall level was not high after experiencing the stage of "mild imbalance → barely coordination"; (3) The spatial characteristics of the three systems are positive spatial autocorrelation, the correlation is gradually enhanced, and the spatial distribution changes to the aggregation state; (4) The high-high agglomeration type is mainly distributed in the southeast coastal and central areas and shows a significant diffusion trend, and the coordinated development level shows a "high southeast and low northwest" trend. Based on the empirical analysis results, suggestions are put forward for the coupling and coordination of digital economy, low-carbon development and new urbanization, in order to provide references for strengthening regional linkage, making up for weaknesses, and promoting green, low-carbon and circular development.
In the face of resource shortage and increasing carbon emissions, how to change the traditional development model and promote the green transformation of the whole society is an important issue to be solved urgently in China to adhere to the green, low-carbon and circular development path. Based on the panel data of 30 provinces in China from 2010 to 2020, this paper constructs an index system and uses the entropy weight TOPSIS model, coupling coordination degree model and spatial autocorrelation model to analyze the coupling coordination degree of digital economy, low-carbon development and new urbanization and its spatio-temporal evolution characteristics. The results show that: (1) From 2010 to 2020, the comprehensive development level of the three systems has significantly improved, showing the spatial distribution characteristics of "high in the east and low in the west"; (2) The coupling coordination degree of the three systems showed a fluctuating upward trend, and the overall level was not high after experiencing the stage of "mild imbalance → barely coordination"; (3) The spatial characteristics of the three systems are positive spatial autocorrelation, the correlation is gradually enhanced, and the spatial distribution changes to the aggregation state; (4) The high-high agglomeration type is mainly distributed in the southeast coastal and central areas and shows a significant diffusion trend, and the coordinated development level shows a "high southeast and low northwest" trend. Based on the empirical analysis results, suggestions are put forward for the coupling and coordination of digital economy, low-carbon development and new urbanization, in order to provide references for strengthening regional linkage, making up for weaknesses, and promoting green, low-carbon and circular development.
Abstract:
[Objective] The spatial distribution prediction of soil total nitrogen and its influencing factors are essential for understanding nitrogen cycle and formulating soil nitrogen management measures. Combined with measured soil total nitrogen content data and multi-source environmental variables, the random forest model was established to explore the spatial distribution characteristics of soil total nitrogen content in a forest farm and the response to environmental factors. [Method] The Wangyedian Experimental Forest Farm was taken as the research area, and a quantitative relationship was established between soil total nitrogen content and environmental covariates of altitude, normalized vegetation index, slope aspect, mean annual temperature, mean annual precipitation and y coordinate at soil depths of 0-10, 10-30 and 30-50 cm using the random forest model. Soil total nitrogen content was predicted and mapped, and the controlling factors affecting its spatial variation were analyzed. [Result] The results showed that (1) the average soil total nitrogen contents at soil depths of 0-10, 10-30 and 30-50 cm were 3.20, 2.02 and 1.47 g kg-1, respectively. It decreased with the increase of soil depth. (2) Cross-validation results showed that the R2 of soil total nitrogen at the three soil depths were 0.54, 0.40 and 0.38, respectively, and the prediction accuracy of the model decreased with the increase of soil depth, indicating that the random forest model could explain 38%~54% of the spatial variation of soil total nitrogen. The effects of various environmental factors on the spatial distribution of soil total nitrogen decreased with the increase of soil depth. (3) Judged from the prognostic map, soil total nitrogen content in different soil depth showed a spatial pattern of low content in the west, north and central parts, and high content in the southwest, southeast and east parts. (4) Altitude had the greatest effect on soil total nitrogen content, and the rest was in the order of normalized vegetation index > mean annual precipitation > y-coordinate > aspect > mean annual temperature. [Conclusion] The random forest model can effectively predict soil total nitrogen content at different soil depths in this forest farm, providing a new idea for the spatial distribution prediction of other soil attributes. Meanwhile, this study provide a reference for forest soil nutrient management and sustainable use on forest farm scale.
[Objective] The spatial distribution prediction of soil total nitrogen and its influencing factors are essential for understanding nitrogen cycle and formulating soil nitrogen management measures. Combined with measured soil total nitrogen content data and multi-source environmental variables, the random forest model was established to explore the spatial distribution characteristics of soil total nitrogen content in a forest farm and the response to environmental factors. [Method] The Wangyedian Experimental Forest Farm was taken as the research area, and a quantitative relationship was established between soil total nitrogen content and environmental covariates of altitude, normalized vegetation index, slope aspect, mean annual temperature, mean annual precipitation and y coordinate at soil depths of 0-10, 10-30 and 30-50 cm using the random forest model. Soil total nitrogen content was predicted and mapped, and the controlling factors affecting its spatial variation were analyzed. [Result] The results showed that (1) the average soil total nitrogen contents at soil depths of 0-10, 10-30 and 30-50 cm were 3.20, 2.02 and 1.47 g kg-1, respectively. It decreased with the increase of soil depth. (2) Cross-validation results showed that the R2 of soil total nitrogen at the three soil depths were 0.54, 0.40 and 0.38, respectively, and the prediction accuracy of the model decreased with the increase of soil depth, indicating that the random forest model could explain 38%~54% of the spatial variation of soil total nitrogen. The effects of various environmental factors on the spatial distribution of soil total nitrogen decreased with the increase of soil depth. (3) Judged from the prognostic map, soil total nitrogen content in different soil depth showed a spatial pattern of low content in the west, north and central parts, and high content in the southwest, southeast and east parts. (4) Altitude had the greatest effect on soil total nitrogen content, and the rest was in the order of normalized vegetation index > mean annual precipitation > y-coordinate > aspect > mean annual temperature. [Conclusion] The random forest model can effectively predict soil total nitrogen content at different soil depths in this forest farm, providing a new idea for the spatial distribution prediction of other soil attributes. Meanwhile, this study provide a reference for forest soil nutrient management and sustainable use on forest farm scale.
Abstract:
In order to explore the basis of climate resource allocation in the production of tobacco leaves for cigar wrapper. Taking“Yunxue-1”variety as the test material，the climate indices during the growth period of tobacco plants was changed by adjusting the transplanting period，and the multivariate statistical analysis method was used to study the basis of climate resource allocation of tobacco leaves for cigar wrapper and its influence on the agronomic traits of tobacco plants and the chemical composition of tobacco leaves after fermentation. The results of correlation analysis showed that The results of correlation analysis showed that the accumulated temperature，≥10℃ effective accumulated temperature，total precipitation and total temperature difference had a great influence on the agronomic traits of tobacco plants，and the correlation coefficient was between 0.478 and 0.939. The accumulated temperature，≥10℃ effective accumulated temperature and average temperature had a great influence on the total sugar, nicotine，total nitrogen and protein content of tobacco leaves，and the correlation coefficient was between -0.955 and -1.000. Through factor analysis，two main factors of climate accumulation factor and humidity factor were both extracted from eight climate indicies. Further through grey correlation analysis found that the above two factors were the main factors affecting the agronomic traits of tobacco plants and the conventional chemical components of tobacco leaves. Therefore，the main climatic factors determining the transplanting period of tobacco plants for cigar wrapper should be based on the comprehensive configuration of temperature，precipitation and relative humidity during the field growth period.
In order to explore the basis of climate resource allocation in the production of tobacco leaves for cigar wrapper. Taking“Yunxue-1”variety as the test material，the climate indices during the growth period of tobacco plants was changed by adjusting the transplanting period，and the multivariate statistical analysis method was used to study the basis of climate resource allocation of tobacco leaves for cigar wrapper and its influence on the agronomic traits of tobacco plants and the chemical composition of tobacco leaves after fermentation. The results of correlation analysis showed that The results of correlation analysis showed that the accumulated temperature，≥10℃ effective accumulated temperature，total precipitation and total temperature difference had a great influence on the agronomic traits of tobacco plants，and the correlation coefficient was between 0.478 and 0.939. The accumulated temperature，≥10℃ effective accumulated temperature and average temperature had a great influence on the total sugar, nicotine，total nitrogen and protein content of tobacco leaves，and the correlation coefficient was between -0.955 and -1.000. Through factor analysis，two main factors of climate accumulation factor and humidity factor were both extracted from eight climate indicies. Further through grey correlation analysis found that the above two factors were the main factors affecting the agronomic traits of tobacco plants and the conventional chemical components of tobacco leaves. Therefore，the main climatic factors determining the transplanting period of tobacco plants for cigar wrapper should be based on the comprehensive configuration of temperature，precipitation and relative humidity during the field growth period.
WU Qiu-xia, YI Qi-xian, CHEN Xi, FAN Xi-bei, TANG Xin-yan, WANG Jin-yun, YIN Ming-xuan, ZHENG Ri-ru, CHEN Sheng-hong, YUAN Hui-hong
Abstract:
In order to detect the volatile components , identify the aroma active substances, and screen the excellent aromatic varieties of Brachyceras water lilies, Headspace solid-phase microextraction combined with gas chromatography-mass spectrometry (HS-SPEM-GC-MS) was conducted to detect volatile compounds in 30 cultivars of Brachyceras water lilies. The results showed that a total of 60 volatile compounds including alkanes, alkenes, terpenes, benzenoids, esters, alcohols and aldehydes were identified. Among them, alkanes and alkenes were the main categories, accounting for 42.43% and 28.61% of the total content, respectively. However, these compounds have trace fragrance characteristics. Furthermore, 19 aroma active compounds were screened by the aroma activity value (OAV). Among them, α-ionone, β-ionone, trans-β-ionone and farnesene were considered as the key characteristic aroma compounds with OAV>1. Ionone endowed water lily woody and sweet fragrance, farnesene endowed apple and typical floral aroma. The results showed that five water lily varieties, 'Blue Bird', 'Carla's Sunshine', 'Eidorado', 'Ruby' and 'Pink Diamond', which were screened based on the OAV value, were potential excellent varieties for landscape application and product processing.
In order to detect the volatile components , identify the aroma active substances, and screen the excellent aromatic varieties of Brachyceras water lilies, Headspace solid-phase microextraction combined with gas chromatography-mass spectrometry (HS-SPEM-GC-MS) was conducted to detect volatile compounds in 30 cultivars of Brachyceras water lilies. The results showed that a total of 60 volatile compounds including alkanes, alkenes, terpenes, benzenoids, esters, alcohols and aldehydes were identified. Among them, alkanes and alkenes were the main categories, accounting for 42.43% and 28.61% of the total content, respectively. However, these compounds have trace fragrance characteristics. Furthermore, 19 aroma active compounds were screened by the aroma activity value (OAV). Among them, α-ionone, β-ionone, trans-β-ionone and farnesene were considered as the key characteristic aroma compounds with OAV>1. Ionone endowed water lily woody and sweet fragrance, farnesene endowed apple and typical floral aroma. The results showed that five water lily varieties, 'Blue Bird', 'Carla's Sunshine', 'Eidorado', 'Ruby' and 'Pink Diamond', which were screened based on the OAV value, were potential excellent varieties for landscape application and product processing.
Abstract:
【Objective】To explore the feasibility and the optimal operation parameters combination of spraying foliar fertilizer on Acanthopanax trifoliatus using unmanned aerial vehicle (UAV).【Method】The experiment of spraying foliar fertilizer was carried out by using XAG P20-2019 quadcopter UVA, the three-factor and three-level orthogonal test was designed, spray quality, yield, and blade quality of Acanthopanax trifoliatus were used as indicators, the effects on spray concentration, flight speed and flight height were investigated.【Result】 The results showed that flight speed and flight height had significantly influence on spray quality, while spray concentration, flight speed and flight height had significantly influence on yield and blade quality of Acanthopanax trifoliatus. Comparing and analyzing the optimal operation parameters of spray quality, yield and blade quality of Acanthopanax trifoliatus, it can be obtained that fertilization effect is best when spray concentration is 5 times the recommended concentration, flight speed is 1.0 m×s-1, and flight height is 2.0m, spray quality is the best and compared with the blank control group, yield increased by 27.46%, and chlorophyll content of Acanthopanax trifoliatus increased by 33.23%.【Conclusion】This paper proved that the feasibility of spraying high concentration foliar fertilizer on Acanthopanax trifoliatus using unmanned aerial vehicle (UAV). This study is expected to improve the mechanized operation level of the planting industry of Acanthopanax trifoliatus and promote it, and provide reference for foliar fertilization using the same type of UVA with the popularization and application value.
【Objective】To explore the feasibility and the optimal operation parameters combination of spraying foliar fertilizer on Acanthopanax trifoliatus using unmanned aerial vehicle (UAV).【Method】The experiment of spraying foliar fertilizer was carried out by using XAG P20-2019 quadcopter UVA, the three-factor and three-level orthogonal test was designed, spray quality, yield, and blade quality of Acanthopanax trifoliatus were used as indicators, the effects on spray concentration, flight speed and flight height were investigated.【Result】 The results showed that flight speed and flight height had significantly influence on spray quality, while spray concentration, flight speed and flight height had significantly influence on yield and blade quality of Acanthopanax trifoliatus. Comparing and analyzing the optimal operation parameters of spray quality, yield and blade quality of Acanthopanax trifoliatus, it can be obtained that fertilization effect is best when spray concentration is 5 times the recommended concentration, flight speed is 1.0 m×s-1, and flight height is 2.0m, spray quality is the best and compared with the blank control group, yield increased by 27.46%, and chlorophyll content of Acanthopanax trifoliatus increased by 33.23%.【Conclusion】This paper proved that the feasibility of spraying high concentration foliar fertilizer on Acanthopanax trifoliatus using unmanned aerial vehicle (UAV). This study is expected to improve the mechanized operation level of the planting industry of Acanthopanax trifoliatus and promote it, and provide reference for foliar fertilization using the same type of UVA with the popularization and application value.
Abstract:
The study of the mechanical properties of water chestnut stalks during the transplanting period can provide a theoretical basis for the mechanization of transplanting. The radial compression test, shear test and bending test were carried out by using TMS-PRO textrometer on the stalks of water chestnut Hubei Water Chestnut No.1 and Dahongpao Water Chestnut from Tuanfeng County, Huanggang City, Hubei Province, China. The results of radial compression test showed that the radial bearing force of the stalks increased sequentially from the top to the bottom, and the average value of the lower part was between 4.0-4.1N; the longer the shelving time (within 4h), the lower the moisture content of the stalks, and the lower the radial bearing force; the effect of the loading rate on the radial bearing force was not significant. The shear test results showed that the lower part of the stalks had the highest shear force, with a mean value between 120-165 N and a shear strength of about 6 MPa; the effect of the 4 hours resting time on the shear force was not significant. The results of the bending test showed that the upper part of the stalk had the smallest bending stiffness, with a mean value between 1.4×10-3-1.6×10-3 Nm2, the middle part had the largest bending modulus of elasticity, with a mean value between 290-405 MPa, and the lower part had the largest cross-sectional moment of inertia, with a mean value between 33-35 mm4, and both were subjected to a significantly higher stress than the upper part and the middle part, with a mean value of the maximum load less than 2 N. The test results can provide a basis for the design of the machine tools for cutting and handling of seedlings, handling and transplanting.
The study of the mechanical properties of water chestnut stalks during the transplanting period can provide a theoretical basis for the mechanization of transplanting. The radial compression test, shear test and bending test were carried out by using TMS-PRO textrometer on the stalks of water chestnut Hubei Water Chestnut No.1 and Dahongpao Water Chestnut from Tuanfeng County, Huanggang City, Hubei Province, China. The results of radial compression test showed that the radial bearing force of the stalks increased sequentially from the top to the bottom, and the average value of the lower part was between 4.0-4.1N; the longer the shelving time (within 4h), the lower the moisture content of the stalks, and the lower the radial bearing force; the effect of the loading rate on the radial bearing force was not significant. The shear test results showed that the lower part of the stalks had the highest shear force, with a mean value between 120-165 N and a shear strength of about 6 MPa; the effect of the 4 hours resting time on the shear force was not significant. The results of the bending test showed that the upper part of the stalk had the smallest bending stiffness, with a mean value between 1.4×10-3-1.6×10-3 Nm2, the middle part had the largest bending modulus of elasticity, with a mean value between 290-405 MPa, and the lower part had the largest cross-sectional moment of inertia, with a mean value between 33-35 mm4, and both were subjected to a significantly higher stress than the upper part and the middle part, with a mean value of the maximum load less than 2 N. The test results can provide a basis for the design of the machine tools for cutting and handling of seedlings, handling and transplanting.
Abstract:
In view of the group's existing air-aspirated miniature potato seed metering devices operation requires high negative pressure, power consumption and seed metering leakage index is too large and other issues, this study based on the radius of curvature of the miniature potato potatoes, designed a ring groove-type seed dispenser disk, in order to increase the effective contact area of the miniature potatoes adhering to the disk, so as to increase the qualification index of the air-aspirated miniature potato seed dispenser. In order to save costs and reduce the research cycle, EDEM and Fluent software are used to construct a coupled simulation system of air-absorbing micro-potato seed metering to simulate the actual working process of the seed dispenser. Among them, due to the coupled simulation requirements of the minimum fluid grid size is larger than the size of the miniature potato, so the bonding model is used instead of multi sphere fitting to establish the miniature potato particles, and the fluid mesh of the seeder adopts the unstructured mesh. In this study, by taking the operation parameters (vacuum degree, seed disks rotation speed) and structural parameters (suction hole diameter, number of suction holes) of the seed discharger as influencing factors, and by taking the qualified index, missed seeding index, reseeding index and power consumption as performance indexes to conduct a single-factor test to obtain the influence law of the influencing factors on the seed discharger, and by designing a quadratic regression orthogonal rotary combinatorial test to obtain the mathematical relationship between the various test indexes of the seed metering devices and the influencing factors. The mathematical relationship between each test index and each influence factor of the seed dispenser is obtained by designing quadratic regression orthogonal rotary combination test. The mathematical model obtained above was solved by non-dominated sorting algorithm (NSGA-II) for multi-objective optimization to obtain the optimal solution set of Pareto, and the optimal solution set was sorted by hierarchical analysis of hierarchies (AHP) to obtain the relationship between the weights of each test index of the seed arranger to get the optimal structure and operating parameters of the seed arranger. The results show that when the negative pressure value of the air suction miniature potato seeder is 5060Pa, the speed of seeding disc is 35r/min, the number of suction holes is 10, and the diameter of suction holes is 10mm, the indexes of the seeder reach the optimum, i.e., the index of the seeder is 94.18%, the index of leakage is 3.14%, the index of replanting is 2.68%, and the power consumption is 10.8kW. verify the simulation optimization results of the air-absorbing miniature potato metering devices, bench tests were carried out according to the optimal parameter combinations. The results show that the simulation optimization results are basically consistent with the bench test, and the relative error of the qualification index is 0.97%. This shows that the combination of multi-objective optimization algorithm and hierarchical analysis process for weight allocation is reasonable and feasible for the performance optimization of seed metering devices.
In view of the group's existing air-aspirated miniature potato seed metering devices operation requires high negative pressure, power consumption and seed metering leakage index is too large and other issues, this study based on the radius of curvature of the miniature potato potatoes, designed a ring groove-type seed dispenser disk, in order to increase the effective contact area of the miniature potatoes adhering to the disk, so as to increase the qualification index of the air-aspirated miniature potato seed dispenser. In order to save costs and reduce the research cycle, EDEM and Fluent software are used to construct a coupled simulation system of air-absorbing micro-potato seed metering to simulate the actual working process of the seed dispenser. Among them, due to the coupled simulation requirements of the minimum fluid grid size is larger than the size of the miniature potato, so the bonding model is used instead of multi sphere fitting to establish the miniature potato particles, and the fluid mesh of the seeder adopts the unstructured mesh. In this study, by taking the operation parameters (vacuum degree, seed disks rotation speed) and structural parameters (suction hole diameter, number of suction holes) of the seed discharger as influencing factors, and by taking the qualified index, missed seeding index, reseeding index and power consumption as performance indexes to conduct a single-factor test to obtain the influence law of the influencing factors on the seed discharger, and by designing a quadratic regression orthogonal rotary combinatorial test to obtain the mathematical relationship between the various test indexes of the seed metering devices and the influencing factors. The mathematical relationship between each test index and each influence factor of the seed dispenser is obtained by designing quadratic regression orthogonal rotary combination test. The mathematical model obtained above was solved by non-dominated sorting algorithm (NSGA-II) for multi-objective optimization to obtain the optimal solution set of Pareto, and the optimal solution set was sorted by hierarchical analysis of hierarchies (AHP) to obtain the relationship between the weights of each test index of the seed arranger to get the optimal structure and operating parameters of the seed arranger. The results show that when the negative pressure value of the air suction miniature potato seeder is 5060Pa, the speed of seeding disc is 35r/min, the number of suction holes is 10, and the diameter of suction holes is 10mm, the indexes of the seeder reach the optimum, i.e., the index of the seeder is 94.18%, the index of leakage is 3.14%, the index of replanting is 2.68%, and the power consumption is 10.8kW. verify the simulation optimization results of the air-absorbing miniature potato metering devices, bench tests were carried out according to the optimal parameter combinations. The results show that the simulation optimization results are basically consistent with the bench test, and the relative error of the qualification index is 0.97%. This shows that the combination of multi-objective optimization algorithm and hierarchical analysis process for weight allocation is reasonable and feasible for the performance optimization of seed metering devices.
Abstract:
In view of the complex environment of paddy field, the end of the discharge port of the existing fertilizer application machinery is easily blocked by soil, resulting in the poor discharge performance of the fertilizer application machine, this paper designs a two-stage fertilizer discharge device, which can then reduce the blockage phenomenon at the end of the discharge port while improving the uniformity and continuity of fertilizer discharge. Firstly, the overall structure of the rice fertilizer application device is designed. The kinematic and kinetic analyses of key components were then carried out, and the results showed that the double gear pitch and gear speed had an important influence on the fertilizer discharge performance of the double-gear fertilizer discharger; the diameter, speed and pitch of the screw shaft had an important influence on the fertilizer discharge performance of the screw fertilizer discharger. The test results show that the uniformity of fertilizer discharge decreases and then increases with the spacing between the two gears, and when the spacing is 5mm, the fertilizer discharge performance of the double-gear fertilizer discharger is better; the coefficient of variation of fertilizer discharge stability increases with the gradual increase of pitch and diameter, and decreases and then increases with the gradual increase of rotational speed, and the combination of spiral shaft diameter, pitch and rotational speed is selected for the test. The best combination of spiral shaft diameter, pitch and rotational speed was determined as 21.292 mm, 134.07 r/min and 16.437 mm pitch, and the coefficient of variation of fertilizer discharge stability was 2.5%. The key components were designed according to the simulation parameters, and the transmission ratio of the double-gear fertilizer discharger and the spiral fertilizer discharger was determined to be 1:4 by combining theoretical calculations and discrete element simulation tests, which resulted in continuous and uniform fertilizer discharge. Finally, a comparison test between the two-stage fertilizer discharger and the spiral fertilizer discharger was conducted, and the test results showed that the consistency, stability and uniformity coefficient of variation of the two-stage fertilizer discharger were improved compared with the spiral fertilizer discharger.
In view of the complex environment of paddy field, the end of the discharge port of the existing fertilizer application machinery is easily blocked by soil, resulting in the poor discharge performance of the fertilizer application machine, this paper designs a two-stage fertilizer discharge device, which can then reduce the blockage phenomenon at the end of the discharge port while improving the uniformity and continuity of fertilizer discharge. Firstly, the overall structure of the rice fertilizer application device is designed. The kinematic and kinetic analyses of key components were then carried out, and the results showed that the double gear pitch and gear speed had an important influence on the fertilizer discharge performance of the double-gear fertilizer discharger; the diameter, speed and pitch of the screw shaft had an important influence on the fertilizer discharge performance of the screw fertilizer discharger. The test results show that the uniformity of fertilizer discharge decreases and then increases with the spacing between the two gears, and when the spacing is 5mm, the fertilizer discharge performance of the double-gear fertilizer discharger is better; the coefficient of variation of fertilizer discharge stability increases with the gradual increase of pitch and diameter, and decreases and then increases with the gradual increase of rotational speed, and the combination of spiral shaft diameter, pitch and rotational speed is selected for the test. The best combination of spiral shaft diameter, pitch and rotational speed was determined as 21.292 mm, 134.07 r/min and 16.437 mm pitch, and the coefficient of variation of fertilizer discharge stability was 2.5%. The key components were designed according to the simulation parameters, and the transmission ratio of the double-gear fertilizer discharger and the spiral fertilizer discharger was determined to be 1:4 by combining theoretical calculations and discrete element simulation tests, which resulted in continuous and uniform fertilizer discharge. Finally, a comparison test between the two-stage fertilizer discharger and the spiral fertilizer discharger was conducted, and the test results showed that the consistency, stability and uniformity coefficient of variation of the two-stage fertilizer discharger were improved compared with the spiral fertilizer discharger.
Yu zhihong, XU Xiao, Zou yong, Chen jianjun, Ye xiaoqing, Zhong guanghua, Lin zhixiong, Li junye, Guan nengchuang
Abstract:
In order to real-time and field nondestructive monitoring the potassium accumulation of flue-cured tobacco in field. Different nitrogen levels was designed and the spatial and temporal distribution and variation of potassium accumulation were studied, the canopy spectral data were also collected to analyze the quantitative relationship between the spatial and temporal distribution of tobacco potassium accumulation and canopy spectral parameters. The results showed that the potassium accumulation in the upper layer is not related to the spectral reflectance except for a few bands. The potassium accumulation in the middle and lower layers is significantly negatively related to the spectral reflectance in the visible light band, while the near-infrared band is significantly positively related. Optimal spectral estimate parameters of each leaf layer potassium accumulation are different. RVI(810,680) is the optimal spectral estimate parameters of upper layer, middle layer, middle-lower layer, and the correlation between DλRed and potassium accumulation of the lower layer, middle-lower layer,the whole plant was the highest. The potassium accumulation spectral estimation model of middle layer, lower layer, upper-middle layer, middle-lower layer and the whole plant are y =-0.002 x2+0.159 x- 0.6531 (R2=0.903**), y = 8.8736x2-4.1032x+0.5164 (R2=0.618**), y =0.0856x1.29 (R2=0.744**), y = 6.6558x2+0.5056x-0.3657 (R2=0.821**), y = 0.2803x0.5774 (R2=0.938**), separately, after verification the model have good stability.Therefore, the estimation model based on spectral parameters could effectively retrieve inversion the potassium accumulation in the middle, lower layers and the whole plant of flue-cured tobacco.
In order to real-time and field nondestructive monitoring the potassium accumulation of flue-cured tobacco in field. Different nitrogen levels was designed and the spatial and temporal distribution and variation of potassium accumulation were studied, the canopy spectral data were also collected to analyze the quantitative relationship between the spatial and temporal distribution of tobacco potassium accumulation and canopy spectral parameters. The results showed that the potassium accumulation in the upper layer is not related to the spectral reflectance except for a few bands. The potassium accumulation in the middle and lower layers is significantly negatively related to the spectral reflectance in the visible light band, while the near-infrared band is significantly positively related. Optimal spectral estimate parameters of each leaf layer potassium accumulation are different. RVI(810,680) is the optimal spectral estimate parameters of upper layer, middle layer, middle-lower layer, and the correlation between DλRed and potassium accumulation of the lower layer, middle-lower layer,the whole plant was the highest. The potassium accumulation spectral estimation model of middle layer, lower layer, upper-middle layer, middle-lower layer and the whole plant are y =-0.002 x2+0.159 x- 0.6531 (R2=0.903**), y = 8.8736x2-4.1032x+0.5164 (R2=0.618**), y =0.0856x1.29 (R2=0.744**), y = 6.6558x2+0.5056x-0.3657 (R2=0.821**), y = 0.2803x0.5774 (R2=0.938**), separately, after verification the model have good stability.Therefore, the estimation model based on spectral parameters could effectively retrieve inversion the potassium accumulation in the middle, lower layers and the whole plant of flue-cured tobacco.
Abstract:
Pig production is an important component of animal husbandry industry in China. Domestic pig production mainly uses self-breeding mode. The semen used in pig reproduction mostly uses fresh semen or diluted semen stored in room temperature, and semen cryopreservation technology can make the long-term preservation of pig semen. Compared with cattle, mice and other species, the cryopreservation technology of pig semen needs to be further optimized and improved. This review summarizes the development of frozen pig semen, the main technical process, the key factors affecting sperm motility after freezing and thawing, including semen collection, pre-cooling balance before freezing, addition of cryoprotectant agents, and cryopreservation methods. It also covers the physicochemical changes during the sperm cryopreservation process, such as physical structural damage, functional damage, and sperm anti-freezing mechanisms. Finally, new methods to improve the cryopreservation efficiency of pig sperm are summarized, including nanotechnology treatment of semen and the study of cryopreservation biomarkers for sperm，in order to provide theoretical reference for perfecting porcine frozen semen technology and accelerating its application in pig production.
Pig production is an important component of animal husbandry industry in China. Domestic pig production mainly uses self-breeding mode. The semen used in pig reproduction mostly uses fresh semen or diluted semen stored in room temperature, and semen cryopreservation technology can make the long-term preservation of pig semen. Compared with cattle, mice and other species, the cryopreservation technology of pig semen needs to be further optimized and improved. This review summarizes the development of frozen pig semen, the main technical process, the key factors affecting sperm motility after freezing and thawing, including semen collection, pre-cooling balance before freezing, addition of cryoprotectant agents, and cryopreservation methods. It also covers the physicochemical changes during the sperm cryopreservation process, such as physical structural damage, functional damage, and sperm anti-freezing mechanisms. Finally, new methods to improve the cryopreservation efficiency of pig sperm are summarized, including nanotechnology treatment of semen and the study of cryopreservation biomarkers for sperm，in order to provide theoretical reference for perfecting porcine frozen semen technology and accelerating its application in pig production.
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Abstract:
In this study,we investigated the effect of bio-floating bed on growth and muscle quality of grass carp (Ctenopharyngodon idellus) and blunt snout bream(Megalobrama amblycephala) in ponds.Two modes of culture ponds were chosen:one equipped with bio-floating bed was the experimental pond,and the other without beds was the control pond.At the end of the experiment,we measured the growth parameters,the muscle conventional nutrients,water holding capacity (WHC),and texture characteristics using biochemical and physical methods.The results showed that the final weight of fish cultured in the experimental pond was higher than that in the control pond.The hepatic somatic index of grass carp (1.77%) in the experimental pond was significantly lower than that of the control (2.47%).The condition factors of grass carp and blunt snout bream (1.73 and 2.56,respectively) were significantly higher than those of the control (1.64 and 2.40,respectively).There was no significant difference in the eviscerated weight of both carp and bream between the experimental (91.06 and 88.28,respectively) and the control (89.22 and 88.49,respectively) ponds.The drop loss (14.49% and 10.69,respectively) and water loss rate (17.52% and 10.34%,respectively) of the experimental grass carp and blunt snout bream were significantly lower than those of the control.The cooked rate of the experimental fish was significantly higher than the control.The muscle crude fat content (1.89%) and crude protein content (14.60%) of grass carp in the experimental ponds were significantly higher than those of the control (1.54% and 13.46%),whereas muscle water content (81.68%) of the experimental fish was significantly lower than that (82.65%) of the control.There is no significant difference in muscle ash content between the two groups.Unlike grass carp,only muscle crude protein content (17.23%) of the experimental bream was significantly higher than that (15.90%) of the control.The muscular hardness,gumminess,and chewiness of the experimental carp (5 298.10 g,2 450.78 g and 770.78 g,respectively) were significantly higher than those of the control (3 226.79 g,1 881.43 g and 602.80 g,respectively).The resilience (0.31) and cohesion (0.48) of experimental carp were significantly lower than those (0.43 and 0.58,respectively) of the control.However,only the muscular springiness of the blunt snout bream in the experimental pond was significantly higher than that in the control pond.
In this study,we investigated the effect of bio-floating bed on growth and muscle quality of grass carp (Ctenopharyngodon idellus) and blunt snout bream(Megalobrama amblycephala) in ponds.Two modes of culture ponds were chosen:one equipped with bio-floating bed was the experimental pond,and the other without beds was the control pond.At the end of the experiment,we measured the growth parameters,the muscle conventional nutrients,water holding capacity (WHC),and texture characteristics using biochemical and physical methods.The results showed that the final weight of fish cultured in the experimental pond was higher than that in the control pond.The hepatic somatic index of grass carp (1.77%) in the experimental pond was significantly lower than that of the control (2.47%).The condition factors of grass carp and blunt snout bream (1.73 and 2.56,respectively) were significantly higher than those of the control (1.64 and 2.40,respectively).There was no significant difference in the eviscerated weight of both carp and bream between the experimental (91.06 and 88.28,respectively) and the control (89.22 and 88.49,respectively) ponds.The drop loss (14.49% and 10.69,respectively) and water loss rate (17.52% and 10.34%,respectively) of the experimental grass carp and blunt snout bream were significantly lower than those of the control.The cooked rate of the experimental fish was significantly higher than the control.The muscle crude fat content (1.89%) and crude protein content (14.60%) of grass carp in the experimental ponds were significantly higher than those of the control (1.54% and 13.46%),whereas muscle water content (81.68%) of the experimental fish was significantly lower than that (82.65%) of the control.There is no significant difference in muscle ash content between the two groups.Unlike grass carp,only muscle crude protein content (17.23%) of the experimental bream was significantly higher than that (15.90%) of the control.The muscular hardness,gumminess,and chewiness of the experimental carp (5 298.10 g,2 450.78 g and 770.78 g,respectively) were significantly higher than those of the control (3 226.79 g,1 881.43 g and 602.80 g,respectively).The resilience (0.31) and cohesion (0.48) of experimental carp were significantly lower than those (0.43 and 0.58,respectively) of the control.However,only the muscular springiness of the blunt snout bream in the experimental pond was significantly higher than that in the control pond.
Abstract:
Effects of soaking temperature,cultivation temperature and watering frequency on the growth characteristics and nutrition of mung bean sprout were investigated. Growth characteristics and nutrition of mung bean sprout were significantly affected by soaking temperature,cultivation temperature and watering frequency (P<0.05). When the bean was soaked at higher temperature (40℃),body weight of the cultivated mung bean sprout was heavier,hypocotyl was longer,contents of free amino acid (FAA),water soluble sugar (WSS) and γ-aminobutyric acid (GABA) were higher. The hypocotyl was longer while the diameter was smaller when the bean was cultivated in the relatively higher temperature (30-35℃). When the watering frequency decreased,weight,hypocotyl length and diameter decreased,WSS content decreased first and then increased,FAA content increased first and then decreased,GABA content was fluctuated. The optimal germination conditions of mung bean sprout were soaking bean at 40℃ for 5 h,with cultivation temperature of 25-30℃ and watering once per hour.
Effects of soaking temperature,cultivation temperature and watering frequency on the growth characteristics and nutrition of mung bean sprout were investigated. Growth characteristics and nutrition of mung bean sprout were significantly affected by soaking temperature,cultivation temperature and watering frequency (P<0.05). When the bean was soaked at higher temperature (40℃),body weight of the cultivated mung bean sprout was heavier,hypocotyl was longer,contents of free amino acid (FAA),water soluble sugar (WSS) and γ-aminobutyric acid (GABA) were higher. The hypocotyl was longer while the diameter was smaller when the bean was cultivated in the relatively higher temperature (30-35℃). When the watering frequency decreased,weight,hypocotyl length and diameter decreased,WSS content decreased first and then increased,FAA content increased first and then decreased,GABA content was fluctuated. The optimal germination conditions of mung bean sprout were soaking bean at 40℃ for 5 h,with cultivation temperature of 25-30℃ and watering once per hour.
2013,32(4):48-54, DOI: 1000-2421（2013）04-0048-07
Abstract:
The spatial distribution of Valley County land use degree in 2009 was studied and the spatial autocorrelation of land use degree and its driving factors in different scales were analyzed.A spatial autoregressive model and geographically weighted regression model was established from the perspective of global local.The results showed that there was a certain spatial autocorrelation in land use degree and its driving factors with scale effect.Spatial regression model could estimate the overall parameter of various factors while geographically weighted regression model could give the local parameter of various factors.Scales of geographical weighted regression model could reflect the detailed geographical information to some extent.
The spatial distribution of Valley County land use degree in 2009 was studied and the spatial autocorrelation of land use degree and its driving factors in different scales were analyzed.A spatial autoregressive model and geographically weighted regression model was established from the perspective of global local.The results showed that there was a certain spatial autocorrelation in land use degree and its driving factors with scale effect.Spatial regression model could estimate the overall parameter of various factors while geographically weighted regression model could give the local parameter of various factors.Scales of geographical weighted regression model could reflect the detailed geographical information to some extent.
Abstract:
pCB302-3 is a plant mini-binary stable transformation vector.To investigate the transient expression of pCB302-3 vector in plant,GFP was inserted into pCB302-3 vector as a reporter gene,and various factors including density of Agrobacterium cell,supplementation of gene silencing suppression p19 and days post infiltration were optimized based on agroinfiltration method in Nicotiana benthamiana leaves.Results showed that high levels of GFP expression were observed in N.benthamiana leaves 3-5 d after infiltration by Agrobacterium cell suspension contained pCB302-3-GFP with an optical density （D600） of 0.8-1.0 co-infiltrated with p19 gene.
pCB302-3 is a plant mini-binary stable transformation vector.To investigate the transient expression of pCB302-3 vector in plant,GFP was inserted into pCB302-3 vector as a reporter gene,and various factors including density of Agrobacterium cell,supplementation of gene silencing suppression p19 and days post infiltration were optimized based on agroinfiltration method in Nicotiana benthamiana leaves.Results showed that high levels of GFP expression were observed in N.benthamiana leaves 3-5 d after infiltration by Agrobacterium cell suspension contained pCB302-3-GFP with an optical density （D600） of 0.8-1.0 co-infiltrated with p19 gene.
2012,31(1):16-22, DOI: 1000-2421（2012）01-0016-07
Abstract:
Nitrogen is one of essential nutrients for plant growth.Under the N deficiency at different time points，the dynamic changes of the expression of genes and activity of enzymes related to nitrogen assimilation in rice were investigated.The results showed that the concentrations of ammonium and nitrate significantly reduced under the N deficiency.Under the N deficiency for a short time，the expression level of genes including NR1, NR2, NiR2,GS2,Fd-GOGAT,GDH2,GDH3 in the shoots as well as NR1,NR2,GDH4 in the roots were up-regulated,and then their expression level decreased after a long time under the N deficiency.Along with the extension of time under the N deficiency,the GS,Fd-GOGAT activities in whole plants,NR activity in shoots and NADH-GOGAT activity in roots decreased while the NADPH-GDH activity in shoots increased.In roots the activities of NR,GDH increased at first and then decreased，while in shoots the NiR activity was just the opposite.Re-supplied N after 7 days of N deficiency,the transcriptional expression level and enzyme activities of NR,NiR,GS,GOGAT,GDH restored,and expression level of some genes increased as well.
Nitrogen is one of essential nutrients for plant growth.Under the N deficiency at different time points，the dynamic changes of the expression of genes and activity of enzymes related to nitrogen assimilation in rice were investigated.The results showed that the concentrations of ammonium and nitrate significantly reduced under the N deficiency.Under the N deficiency for a short time，the expression level of genes including NR1, NR2, NiR2,GS2,Fd-GOGAT,GDH2,GDH3 in the shoots as well as NR1,NR2,GDH4 in the roots were up-regulated,and then their expression level decreased after a long time under the N deficiency.Along with the extension of time under the N deficiency,the GS,Fd-GOGAT activities in whole plants,NR activity in shoots and NADH-GOGAT activity in roots decreased while the NADPH-GDH activity in shoots increased.In roots the activities of NR,GDH increased at first and then decreased，while in shoots the NiR activity was just the opposite.Re-supplied N after 7 days of N deficiency,the transcriptional expression level and enzyme activities of NR,NiR,GS,GOGAT,GDH restored,and expression level of some genes increased as well.
2013,32(5):124-133, DOI: 1000-2421（2013）05-0124-10
Abstract:
Bacterial canker is a devastating disease of kiwifruit. In recent years,the disease is showing a tendency to outbreak in such countries as Italy and New Zealand,where kiwifruit is a major crop,and has the trends to further spread worldwide,which will be a serious threat to the development of the kiwifruit industry. Based on the latest research reports, this paper summarized the symptoms,pathogen identification,rapid detection methods,virulence differences,infected mechanism,epidemiology and control technology of the disease. Meanwhile,the future research prospect of kiwifruit bacterial canker was also discussed in order to reduce the loss and risk of the kiwifruit industry.
Bacterial canker is a devastating disease of kiwifruit. In recent years,the disease is showing a tendency to outbreak in such countries as Italy and New Zealand,where kiwifruit is a major crop,and has the trends to further spread worldwide,which will be a serious threat to the development of the kiwifruit industry. Based on the latest research reports, this paper summarized the symptoms,pathogen identification,rapid detection methods,virulence differences,infected mechanism,epidemiology and control technology of the disease. Meanwhile,the future research prospect of kiwifruit bacterial canker was also discussed in order to reduce the loss and risk of the kiwifruit industry.
Abstract:
In order to overcome the transition，field operation, and standardized batch production difficulties of the existing track cargo vehicle in mountainous orchard, as well as to raise the utilization rate, the mountain orchard detachable unidirectional traction double track cargo vehicle was developed. This paper introduced the whole machine structure, the wire rope diameter selection，the minimum track inclination，the maximum track distance，the minimum track turning radius and the working principle of the rope brake device. Load experiments were carried out to test the cargo′s synthetic track function. It is indicated by calculation that the wire rope diameter should be 7.7 mm，the minimum track inclination was 5.7°, the maximum track distance was 170 m, the minimum track horizontal turning radius was 7 m, and the minimum track vertical turning radius was 2 m. Load experiment results indicated that the cargo vehicle′s uplink average speed was 0.51 m/s, the downlink average speed was 0.54 m/s, the average energy consumption was 1.235 kW·h and the effective use degree was 100%. This cargo vehicle was suitable for fruit, pesticide, chemical fertilizer and other cargo transportation in the mountain orchard. Meanwhile, it can be applied to carry the spraying machine, the shave machine and other agricultural machines.
In order to overcome the transition，field operation, and standardized batch production difficulties of the existing track cargo vehicle in mountainous orchard, as well as to raise the utilization rate, the mountain orchard detachable unidirectional traction double track cargo vehicle was developed. This paper introduced the whole machine structure, the wire rope diameter selection，the minimum track inclination，the maximum track distance，the minimum track turning radius and the working principle of the rope brake device. Load experiments were carried out to test the cargo′s synthetic track function. It is indicated by calculation that the wire rope diameter should be 7.7 mm，the minimum track inclination was 5.7°, the maximum track distance was 170 m, the minimum track horizontal turning radius was 7 m, and the minimum track vertical turning radius was 2 m. Load experiment results indicated that the cargo vehicle′s uplink average speed was 0.51 m/s, the downlink average speed was 0.54 m/s, the average energy consumption was 1.235 kW·h and the effective use degree was 100%. This cargo vehicle was suitable for fruit, pesticide, chemical fertilizer and other cargo transportation in the mountain orchard. Meanwhile, it can be applied to carry the spraying machine, the shave machine and other agricultural machines.
2014,33(2):139-144, DOI: 1000-2421（2014）02-0139-06
Abstract:
Algae are lower photosynthetic autotrophs which have close relationship with agricultural activities.With the deep understanding of physiological and ecological characteristics,algae have used more and more widelyin the practice of agricultural activities.This paper reviews the application of algaeas a resourcein agricultural activities including improvement of agricultural environment,utilized as food or food additives and health care products,as well as feed or bait.
Algae are lower photosynthetic autotrophs which have close relationship with agricultural activities.With the deep understanding of physiological and ecological characteristics,algae have used more and more widelyin the practice of agricultural activities.This paper reviews the application of algaeas a resourcein agricultural activities including improvement of agricultural environment,utilized as food or food additives and health care products,as well as feed or bait.
Abstract:
The development of Golden Rice to date has taken longer than anticipated.It has been proven to have the potential to assist in the alleviation of an important public health problem,vitamin A deficiency,affecting millions.Complying with the highly precautionary,and now proven unnecessary,UN Cartagena Protocol for Biosafety has impeded scientific progress and scientific collaboration,particularly by delaying the selection of phenotypes grown in the open field.So far therefore,Golden Rice has not been able to assist in combatting vitamin A deficiency,identified by the UN as an important public health target for 25 years,and which continues to cause preventable deaths and blindness.However,the inventor’s original vision of the donation of the technology to assist the resource poor who want to benefit from it remains firm and achievable,subject to continuing philanthropic and public sector funding.
The development of Golden Rice to date has taken longer than anticipated.It has been proven to have the potential to assist in the alleviation of an important public health problem,vitamin A deficiency,affecting millions.Complying with the highly precautionary,and now proven unnecessary,UN Cartagena Protocol for Biosafety has impeded scientific progress and scientific collaboration,particularly by delaying the selection of phenotypes grown in the open field.So far therefore,Golden Rice has not been able to assist in combatting vitamin A deficiency,identified by the UN as an important public health target for 25 years,and which continues to cause preventable deaths and blindness.However,the inventor’s original vision of the donation of the technology to assist the resource poor who want to benefit from it remains firm and achievable,subject to continuing philanthropic and public sector funding.
Abstract:
Soil salinity is a major environmental constraint to agricultural productivity.It is a complex network for plant adaptation to salt stress,and it is still a great challenge to improve crop salt tolerance.Mechanisms of SOS signal transduction pathway on Na+ exclusion and compartmentation,the regulation of microRNA and transcription factors involved in salt stress were reviewed.It will provide a fundamental understanding and knowledge for studying salt resistance and breeding salt tolerance in plants.
Soil salinity is a major environmental constraint to agricultural productivity.It is a complex network for plant adaptation to salt stress,and it is still a great challenge to improve crop salt tolerance.Mechanisms of SOS signal transduction pathway on Na+ exclusion and compartmentation,the regulation of microRNA and transcription factors involved in salt stress were reviewed.It will provide a fundamental understanding and knowledge for studying salt resistance and breeding salt tolerance in plants.
Abstract:
Using Mesorhizobium sp.S-15 and Paenibacillus sp.S-17 as experimental strains.After cell disruption,NH4OAc extraction,H2O2 solution digestion or without any pre-treatment,K+ content in the fermentation broth of potassium solubilizing bacteria was determined with flame photometer.The efficiency of K solubilizing by potassium solubilizing bacteria in the culture medium was calculated.The results showed that the standard curves of the three kinds of K series of standard solutions were similar with the R2 values of 0.994 4,0.999 7 and 0.999 8,respectively.After digested by H2O2 solution,concentration of K+ was detected.The efficiency of two strains was 101.1% and 125.1%,significantly higher than that of other groups.The efficiency of potassium solubilizing detected after H2O2 digestion well reflected potassium solubilization of bacteria.
Using Mesorhizobium sp.S-15 and Paenibacillus sp.S-17 as experimental strains.After cell disruption,NH4OAc extraction,H2O2 solution digestion or without any pre-treatment,K+ content in the fermentation broth of potassium solubilizing bacteria was determined with flame photometer.The efficiency of K solubilizing by potassium solubilizing bacteria in the culture medium was calculated.The results showed that the standard curves of the three kinds of K series of standard solutions were similar with the R2 values of 0.994 4,0.999 7 and 0.999 8,respectively.After digested by H2O2 solution,concentration of K+ was detected.The efficiency of two strains was 101.1% and 125.1%,significantly higher than that of other groups.The efficiency of potassium solubilizing detected after H2O2 digestion well reflected potassium solubilization of bacteria.
Abstract:
This review of the safety assessment of genetically modified (GM) crops is focused primarily on the process and progress in the United States (US). It reviews the development of the safety evaluation process from the Asilomar conference in 1975 considering issues relevant to recombinant DNA technology,to discussions between the US government,academic and industrial scientists between 1984 and 1994 when the first GM crops were being field tested and evaluated commercial release for food and feed production. International guidelines were also reviewed for consistency with the US system. The overall process includes consideration of information relating to history of safe or unsafe human and exposure to the gene source and expressed proteins. The primary considerations of safety for dietary proteins are whether or not some consumers are sensitized and have IgE antibodies against the protein encoded by the transgene or whether the transgene represents a risk of eliciting celiac disease. The process considers potential toxic effects of expressed proteins as well as potential impacts on human and animal nutrition. The process in the US is consistent with Codex Alimentarius recommendations. It follows a science based process based on justifiable hypotheses. To date there is no evidence that GM crops approved in the US have harmed human or animal consumers. The evaluation takes into account genetic and environmental variation in products produced by plant varieties and is intended to maintain the standard that foods developed from GM plants are intended to be as safe as non-GM genetically similar varieties.
This review of the safety assessment of genetically modified (GM) crops is focused primarily on the process and progress in the United States (US). It reviews the development of the safety evaluation process from the Asilomar conference in 1975 considering issues relevant to recombinant DNA technology,to discussions between the US government,academic and industrial scientists between 1984 and 1994 when the first GM crops were being field tested and evaluated commercial release for food and feed production. International guidelines were also reviewed for consistency with the US system. The overall process includes consideration of information relating to history of safe or unsafe human and exposure to the gene source and expressed proteins. The primary considerations of safety for dietary proteins are whether or not some consumers are sensitized and have IgE antibodies against the protein encoded by the transgene or whether the transgene represents a risk of eliciting celiac disease. The process considers potential toxic effects of expressed proteins as well as potential impacts on human and animal nutrition. The process in the US is consistent with Codex Alimentarius recommendations. It follows a science based process based on justifiable hypotheses. To date there is no evidence that GM crops approved in the US have harmed human or animal consumers. The evaluation takes into account genetic and environmental variation in products produced by plant varieties and is intended to maintain the standard that foods developed from GM plants are intended to be as safe as non-GM genetically similar varieties.
2012,31(1):127-132, DOI: 1000-2421（2012）01-0127-06
Abstract:
Post-harvest strawberries are susceptible to the decay of fruit and deterioration of quality due to pathogenic fungi infections,a main factor leading to economic losses for both growers and retailers.With the increase of strawberries planting in China,it is urgent to effectively reduce post-harvest rots of strawberry fruits.In this review,new management developments for controlling fungal diseases in post-harvest strawberry were summarized in terms of physical,chemical and biological approaches,which can help to extend the on-shelf time of strawberry fruits.
Post-harvest strawberries are susceptible to the decay of fruit and deterioration of quality due to pathogenic fungi infections,a main factor leading to economic losses for both growers and retailers.With the increase of strawberries planting in China,it is urgent to effectively reduce post-harvest rots of strawberry fruits.In this review,new management developments for controlling fungal diseases in post-harvest strawberry were summarized in terms of physical,chemical and biological approaches,which can help to extend the on-shelf time of strawberry fruits.
2012,31(5):569-573, DOI: 1000-2421（2012）05-0569-05
Abstract:
Hydroponic experiments of strawberry were conducted with three formulations of nutrient solution to select the best formulations for soilless cultivation of strawberry.Several main characteristics of growth including the fresh weight and dry weight of overground plant and root，the growth of crown，the photosynthetic and quality of strawberry，the diameter of staminate flower，the growth amass were investigated．The results showed that the effect of nutrient solution with the content of calcium nitrate tetrahydrate,potassium nitrate,ammonium dihydrogen phosphate,magnesium sulfate and ammonium nitrate at 295,303,62,246,0 mg/L on the growing status and fruit quality of strawberry are better than that of the other 2 treatments.This nutrient solution formula was the most propitious for the growth of ‘Jingyao’ strawberry and the enhancement of the fruit quality among the three different treatnments.That is,it facilitated the growth of strawberry in alimentation growth periods,and the leaves of ‘Jingyao’ strawberry was larger and thicker with a dark-green color,and the diameter of the pedicel was also larger. In addition,the nutrient solution formula was also conducive to the flowering promotion and the reproductive growth of strawberry,and resultes showed that the single fruit weight,yield and fruit quality is the best comparing to the other treatments.The results of this study provided academic and technological basis for establishing high yield and quality of strawberry in greenhouse substrate culture of irrigation and nitrogen application system.
Hydroponic experiments of strawberry were conducted with three formulations of nutrient solution to select the best formulations for soilless cultivation of strawberry.Several main characteristics of growth including the fresh weight and dry weight of overground plant and root，the growth of crown，the photosynthetic and quality of strawberry，the diameter of staminate flower，the growth amass were investigated．The results showed that the effect of nutrient solution with the content of calcium nitrate tetrahydrate,potassium nitrate,ammonium dihydrogen phosphate,magnesium sulfate and ammonium nitrate at 295,303,62,246,0 mg/L on the growing status and fruit quality of strawberry are better than that of the other 2 treatments.This nutrient solution formula was the most propitious for the growth of ‘Jingyao’ strawberry and the enhancement of the fruit quality among the three different treatnments.That is,it facilitated the growth of strawberry in alimentation growth periods,and the leaves of ‘Jingyao’ strawberry was larger and thicker with a dark-green color,and the diameter of the pedicel was also larger. In addition,the nutrient solution formula was also conducive to the flowering promotion and the reproductive growth of strawberry,and resultes showed that the single fruit weight,yield and fruit quality is the best comparing to the other treatments.The results of this study provided academic and technological basis for establishing high yield and quality of strawberry in greenhouse substrate culture of irrigation and nitrogen application system.
2014,33(2):15-21, DOI: 1000-2421（2014）02-0015-07
Abstract:
Teosinte is the ancestor of maize,and plays an important role in maize domestication process and gene cloning.Solexa RNA-Seq was used to de novo assembly and analyze the transcriptome of teosintes.40.6 GB raw data were produced,including 175 101 250 reads of 76 bp length.After quality control and de novo assembly,58 147 teosinte transcripts with an average length of 1 335 bp were obtained.After bioinformatically comparing,it was found that 94.3% of teosinte transcripts had good matching with B73 cDNAs,and that 84.1% of the transcript had good matching with rice,84.6% with sorghum and 83.9% with brachypodium at protein level.This research will provide a reference for subsequent studies on maize evolution and gene discovery.
Teosinte is the ancestor of maize,and plays an important role in maize domestication process and gene cloning.Solexa RNA-Seq was used to de novo assembly and analyze the transcriptome of teosintes.40.6 GB raw data were produced,including 175 101 250 reads of 76 bp length.After quality control and de novo assembly,58 147 teosinte transcripts with an average length of 1 335 bp were obtained.After bioinformatically comparing,it was found that 94.3% of teosinte transcripts had good matching with B73 cDNAs,and that 84.1% of the transcript had good matching with rice,84.6% with sorghum and 83.9% with brachypodium at protein level.This research will provide a reference for subsequent studies on maize evolution and gene discovery.
2011,30(4):488-493, DOI: 1000-2421（2011）04-0488-06
Abstract:
The morphological variations and discriminant methods of Channa argus (♂)，C.maculata (♀) and their hybrid were studied using traditional morphometrics and the truss network analysis.Body color of C.argus,C.maculata and their hybrid were observed.The results showed significant differences between C.argus and C.maculata from stripe at top of head,side and base of caudal fin,and the hybrid resembled C.maculata from body color.Among eleven meristic characters,the numbers of soft ray of pelvic fin were consistent in these three species,and the numbers of soft ray of pectoral fin deviated from its male parent’s species.The other meristic characters were within the range of its parent’s,the average hybrid index was calculated to be 53.45.The chi-square analysis of meristic characters showed that:there were significant differences(P<0.05) or greater significant differences(P<0.01) between C.argus and C.maculata except the number of pectoral fin rays; greater significant differences(P<0.01) between C.argus and the hybrid except the number of tail fin rays,gill rakers,lateral line scales and scales below lateral line; and significant differences(P<0.05) or greater significant differences(P<0.01) between C.maculata and the hybrid except the number of tail fin rays and gill rakers.Among meristic characters,the number of dorsal fin rays,lateral line scales and scales above lateral line can be used as preliminary indicators to determine the three species.Among ten measurable characters,the average hybrid index was calculated to be 73.90,indicating the measurable character inclined to its male parent’s species (C.argus).Cluster analysis,discriminant analysis and principal component analysis were applied to the measurable character data and the truss network data.The results indicated that the hybrid resembled C.argus from body shape,and there were greater morphological differences among C.argus,C.maculata and their hybrid.Differences between them involved the entire body.Three species could be distinguished by using the 3 formulae established with discriminant analysis which the discrimination accuracy was 100.0%.
The morphological variations and discriminant methods of Channa argus (♂)，C.maculata (♀) and their hybrid were studied using traditional morphometrics and the truss network analysis.Body color of C.argus,C.maculata and their hybrid were observed.The results showed significant differences between C.argus and C.maculata from stripe at top of head,side and base of caudal fin,and the hybrid resembled C.maculata from body color.Among eleven meristic characters,the numbers of soft ray of pelvic fin were consistent in these three species,and the numbers of soft ray of pectoral fin deviated from its male parent’s species.The other meristic characters were within the range of its parent’s,the average hybrid index was calculated to be 53.45.The chi-square analysis of meristic characters showed that:there were significant differences(P<0.05) or greater significant differences(P<0.01) between C.argus and C.maculata except the number of pectoral fin rays; greater significant differences(P<0.01) between C.argus and the hybrid except the number of tail fin rays,gill rakers,lateral line scales and scales below lateral line; and significant differences(P<0.05) or greater significant differences(P<0.01) between C.maculata and the hybrid except the number of tail fin rays and gill rakers.Among meristic characters,the number of dorsal fin rays,lateral line scales and scales above lateral line can be used as preliminary indicators to determine the three species.Among ten measurable characters,the average hybrid index was calculated to be 73.90,indicating the measurable character inclined to its male parent’s species (C.argus).Cluster analysis,discriminant analysis and principal component analysis were applied to the measurable character data and the truss network data.The results indicated that the hybrid resembled C.argus from body shape,and there were greater morphological differences among C.argus,C.maculata and their hybrid.Differences between them involved the entire body.Three species could be distinguished by using the 3 formulae established with discriminant analysis which the discrimination accuracy was 100.0%.
2014,33(01):12-17, DOI: 1000-2421（2014）01-0012-06
Abstract:
Seventeen pairs of SSR primers with clear polymorphic bands were screened from 60 pairs of SSR locus covering 17 linkage groups of pear genetic map and amplified with 20 pear cultivars.136 polymorphic bands in total were obtained with 5~11 bands per primer locus (8.0 bands on average).The polymorphism information content (PIC) of the 17 SSR loci ranged from 0.614 to 0.848 with an average of 0.733.All pear cultivars studied could be identified with 38 different combinations of 2 markers each.Bands amplified by each marker were coded based on size of fragment and used as a molecular ID.
Seventeen pairs of SSR primers with clear polymorphic bands were screened from 60 pairs of SSR locus covering 17 linkage groups of pear genetic map and amplified with 20 pear cultivars.136 polymorphic bands in total were obtained with 5~11 bands per primer locus (8.0 bands on average).The polymorphism information content (PIC) of the 17 SSR loci ranged from 0.614 to 0.848 with an average of 0.733.All pear cultivars studied could be identified with 38 different combinations of 2 markers each.Bands amplified by each marker were coded based on size of fragment and used as a molecular ID.
2011,30(5):613-617, DOI: 1000-2421（2011）05-0613-05
Abstract:
Pot experiment was conducted to study the effects of spraying different micronutrients and amino acids into the surface of leaves on yield and quality of Chinese cabbage (Brassica rapa L.).The results showed that methionine,zinc,molybdenum,boron and glycine could increase yield of Chinese cabbage.The treatments of spraying methionine,zinc and molybdenum increased yield of Chinese cabbage significantly.All treatments could reduce the nitrate content of Chinese cabbage with the highest decrease of 35.0% compared with the control.Molybdenum,boron,zinc and methionine might reduce nitrate content of Chinese cabbage significantly.Experiment also indicated that glycine,proline and selenium could both increase the contents of vitamin C,soluble sugar and soluble protein of Chinese cabbage.Therefore,spraying micronutrient or amino acids into the surface of leaves is a good application for increasing yield,reducing nitrate content and improving quality of Chinese cabbage.
Pot experiment was conducted to study the effects of spraying different micronutrients and amino acids into the surface of leaves on yield and quality of Chinese cabbage (Brassica rapa L.).The results showed that methionine,zinc,molybdenum,boron and glycine could increase yield of Chinese cabbage.The treatments of spraying methionine,zinc and molybdenum increased yield of Chinese cabbage significantly.All treatments could reduce the nitrate content of Chinese cabbage with the highest decrease of 35.0% compared with the control.Molybdenum,boron,zinc and methionine might reduce nitrate content of Chinese cabbage significantly.Experiment also indicated that glycine,proline and selenium could both increase the contents of vitamin C,soluble sugar and soluble protein of Chinese cabbage.Therefore,spraying micronutrient or amino acids into the surface of leaves is a good application for increasing yield,reducing nitrate content and improving quality of Chinese cabbage.
2010,29(3):363-368, DOI: 1000-2421(2010)03-0363-06
Abstract:
The index of heat injury and leaf anatomical structure under the scanning electron microscope of six Primula species were measured to study the responsive mechanism of Primula to the high temperature and to select the heat resistant Primula species.The results showed that Primula forrestii and P.malacoides franch had higher heat-resistance than that of P.obconica,P.veris,P.saxatilis,P.denticulatess.,P.sinodenticulata with lowest heat-resistance.Leaf anatomical structures of Primula associated with heat-resistance included leaf thickness,tightness of mesophyll cell arrangement,the number of open stomata,the number of epidermal hair and powders of leaves.
The index of heat injury and leaf anatomical structure under the scanning electron microscope of six Primula species were measured to study the responsive mechanism of Primula to the high temperature and to select the heat resistant Primula species.The results showed that Primula forrestii and P.malacoides franch had higher heat-resistance than that of P.obconica,P.veris,P.saxatilis,P.denticulatess.,P.sinodenticulata with lowest heat-resistance.Leaf anatomical structures of Primula associated with heat-resistance included leaf thickness,tightness of mesophyll cell arrangement,the number of open stomata,the number of epidermal hair and powders of leaves.
2014,33(2):96-102, DOI: 1000-2421（2014）02-0096-07
Abstract:
A 90-day study was conducted to investigate effects of dietary lipid levels on performance,fat deposition,activity and expression of lipoprotein lipase (LPL) in GIFT tilapia (Oreochromis niloticus) juvenile,and to explore the correlation between LPL gene expression and fat deposition.315 GIFT tilapia juveniles(average weight 2.63±0.16 g) were randomly divided into three groups with three replications,and fed with isonitrogenous diets with different lipid levels of 3.7% (low-lipid group),7.7%(middle-lipid group)and 16.6% (high-lipid group) by supplementing with 2%,6% and 15% fish oil as lipid source,respectively.The results showed:(1) the hepatosomatic index (HSI),viscerosomatic index (VSI) and lipid contents in liver and muscle increased with increasing dietary lipid level(P＜0.05),but there was a trends for condition factor (CF) with first increased then decreased (P＞0.05); (2)with increasing dietary lipid levels, the weight gain (WG) first increased, then decreased, and feed conversion ratio (FCR) decreased(P＜0.05); (3)LPL gene was expressed in liver and muscle of GIFT tilapia,while the expression level in liver was significantly higher than that in muscle (P＜0.05); (4) during the 48 h post-refeeding period,liver LPL activity in high-lipid group was significantly higher than that in low-lipid and middle-lipid group at 6 h,but significantly lower than that in low-lipid group at the 12 h,24 h and 48 h.There was a trend in low-lipid and middle-lipid group that liver LPL activity increased first and then decreased; (5) the expression of LPL was significantly higher in high-lipid group than that in low-lipid group (P＜0.05); (6) there were a significant linear positive correlation between HSI,lipid contents in liver and muscle,and liver LPL expression in GIFT tilapia juvenile.The results indicated that LPL expression in GIFT tilapia was in a tissue specific pattern and liver was the main organ for secretion and expression of LPL; high dietary lipid level could inhibit growth of GIFT tilapia juvenile,decrease feed conversion ratio,induce the expression of LPL in liver,and promote fat deposition in liver and muscle; liver LPL expression was involved in fat deposition of GIFT tilapia juvenile.
A 90-day study was conducted to investigate effects of dietary lipid levels on performance,fat deposition,activity and expression of lipoprotein lipase (LPL) in GIFT tilapia (Oreochromis niloticus) juvenile,and to explore the correlation between LPL gene expression and fat deposition.315 GIFT tilapia juveniles(average weight 2.63±0.16 g) were randomly divided into three groups with three replications,and fed with isonitrogenous diets with different lipid levels of 3.7% (low-lipid group),7.7%(middle-lipid group)and 16.6% (high-lipid group) by supplementing with 2%,6% and 15% fish oil as lipid source,respectively.The results showed:(1) the hepatosomatic index (HSI),viscerosomatic index (VSI) and lipid contents in liver and muscle increased with increasing dietary lipid level(P＜0.05),but there was a trends for condition factor (CF) with first increased then decreased (P＞0.05); (2)with increasing dietary lipid levels, the weight gain (WG) first increased, then decreased, and feed conversion ratio (FCR) decreased(P＜0.05); (3)LPL gene was expressed in liver and muscle of GIFT tilapia,while the expression level in liver was significantly higher than that in muscle (P＜0.05); (4) during the 48 h post-refeeding period,liver LPL activity in high-lipid group was significantly higher than that in low-lipid and middle-lipid group at 6 h,but significantly lower than that in low-lipid group at the 12 h,24 h and 48 h.There was a trend in low-lipid and middle-lipid group that liver LPL activity increased first and then decreased; (5) the expression of LPL was significantly higher in high-lipid group than that in low-lipid group (P＜0.05); (6) there were a significant linear positive correlation between HSI,lipid contents in liver and muscle,and liver LPL expression in GIFT tilapia juvenile.The results indicated that LPL expression in GIFT tilapia was in a tissue specific pattern and liver was the main organ for secretion and expression of LPL; high dietary lipid level could inhibit growth of GIFT tilapia juvenile,decrease feed conversion ratio,induce the expression of LPL in liver,and promote fat deposition in liver and muscle; liver LPL expression was involved in fat deposition of GIFT tilapia juvenile.
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Huazhong A gricultural University
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ZHANG Xianlong
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