显示方式：
2024,43(4):1-2
, DOI: 10.13300/j.cnki.hnlkxb.2024.04.001
Abstract:
2024,43(4):3-11
, DOI: 10.13300/j.cnki.hnlkxb.2024.04.002
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 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 for further studying LysM-RLKs genes in M. truncatula.
2024,43(4):12-24
, DOI: 10.13300/j.cnki.hnlkxb.2024.04.003
Abstract:
Senescence is one of the major factors affecting the efficiency of nitrogen fixation in legume nodules， and in-depth studying the regulatory mechanisms of the senescence of nodule is of great significance. This article reviewed the progress on studying the senescence of nodule from the aspects including morphological characteristics， physiological and biochemical changes， pathways of senescence， and the regulation of material metabolism. The functions of senescence-related genes in both legume and rhizobia during the process of symbiotic nitrogen fixation were summarized. It is put forward that developing new methods and technologies of studying can contribute to a more thorough elucidation of the molecular mechanisms underlying the metabolism of key substances in the senescence of nodules. A thorough understanding of the molecular mechanisms of the senescence of nodule can be helpful for the genetic modification of delaying the senescence of nodule， thereby improving the efficiency of nitrogen fixation in leguminous plants and promoting the sustainable development of agricultural production.
Senescence is one of the major factors affecting the efficiency of nitrogen fixation in legume nodules， and in-depth studying the regulatory mechanisms of the senescence of nodule is of great significance. This article reviewed the progress on studying the senescence of nodule from the aspects including morphological characteristics， physiological and biochemical changes， pathways of senescence， and the regulation of material metabolism. The functions of senescence-related genes in both legume and rhizobia during the process of symbiotic nitrogen fixation were summarized. It is put forward that developing new methods and technologies of studying can contribute to a more thorough elucidation of the molecular mechanisms underlying the metabolism of key substances in the senescence of nodules. A thorough understanding of the molecular mechanisms of the senescence of nodule can be helpful for the genetic modification of delaying the senescence of nodule， thereby improving the efficiency of nitrogen fixation in leguminous plants and promoting the sustainable development of agricultural production.
CHEN Yanzhao, XU Shulin, QU Chenchen, ZHANG Ming, GAO Chunhui, WU Yichao, DAI Ke, HUANG Qiaoyun, CAI Peng
2024,43(4):25-32
, DOI: 10.13300/j.cnki.hnlkxb.2024.04.004
Abstract:
Interfacial reaction is the foundation and prerequisite for bacteria to adhere，colonize，form biofilms，and perform ecological functions in the environment. It is of great significance for plants to absorb nutrients and antagonize pathogenic microorganisms. Most studies on the microbe-plant rhizosphere interactions are conducted from the perspectives of ecology and molecular biology，using multi-omics methods to study the effects of root exudates on the quantity of colonization，the composition of community，and the physiological functions of rhizosphere microorganisms. However，the physical and chemical interfacial mechanisms involved in bacterial colonization and their contributions to adhesion have been ignored. This article reviewed the regulatory effects of different types of root exudates on the properties of bacterial surface，the molecular composition of extracellular polymeric substances （EPS），and the function of adhesion in term of the mechanisms of interfacial interactions. The main modes and micro mechanisms of the interaction between bacteria and plant bio-macromolecules during the process of adhesion were summarized. The visualization methods for studying the process of rhizosphere colonization and methods for analyzing the interaction between microorganisms and plant bio-macromolecules were discussed. The directions of studies that urgently need to be strengthened including analyzing the biomolecular composition of rhizosphere，predicting the function of adhesion protein，and the in situ methods for observing the colonization of rhizosphere were proposed.
Interfacial reaction is the foundation and prerequisite for bacteria to adhere，colonize，form biofilms，and perform ecological functions in the environment. It is of great significance for plants to absorb nutrients and antagonize pathogenic microorganisms. Most studies on the microbe-plant rhizosphere interactions are conducted from the perspectives of ecology and molecular biology，using multi-omics methods to study the effects of root exudates on the quantity of colonization，the composition of community，and the physiological functions of rhizosphere microorganisms. However，the physical and chemical interfacial mechanisms involved in bacterial colonization and their contributions to adhesion have been ignored. This article reviewed the regulatory effects of different types of root exudates on the properties of bacterial surface，the molecular composition of extracellular polymeric substances （EPS），and the function of adhesion in term of the mechanisms of interfacial interactions. The main modes and micro mechanisms of the interaction between bacteria and plant bio-macromolecules during the process of adhesion were summarized. The visualization methods for studying the process of rhizosphere colonization and methods for analyzing the interaction between microorganisms and plant bio-macromolecules were discussed. The directions of studies that urgently need to be strengthened including analyzing the biomolecular composition of rhizosphere，predicting the function of adhesion protein，and the in situ methods for observing the colonization of rhizosphere were proposed.
2024,43(4):33-40
, DOI: 10.13300/j.cnki.hnlkxb.2024.04.005
Abstract:
Consolidated bioprocessing （CBP） is considered as the most ideal form for lignocellulose conversion. Although the modification of metabolic engineering can achieve CBP based on a single strain， excessive metabolic pressure alone leads to the suboptimal transformation efficiency of strain. This article focused on the interspecific division in the microbial community of degrading natural lignocellulosic to systematically understand the interspecific division of labor and realize the rational design of CBP. The current patterns of interspecific division of labor were reviewed in terms of the synergistic hydrolysis of substrate， the cross-feeding of nutritional factors， and the restriction of “sugar cheaters”. The application of interspecific division of labor in lignocellulose conversion， the challenges and development directions of studying interspecific division in microbial communities of natural lignocellulose were introduced. It will provide principles for designing the construction of a microbial community with consolidated bioprocessing to promote the efficient biotransformation of lignocellulose.
Consolidated bioprocessing （CBP） is considered as the most ideal form for lignocellulose conversion. Although the modification of metabolic engineering can achieve CBP based on a single strain， excessive metabolic pressure alone leads to the suboptimal transformation efficiency of strain. This article focused on the interspecific division in the microbial community of degrading natural lignocellulosic to systematically understand the interspecific division of labor and realize the rational design of CBP. The current patterns of interspecific division of labor were reviewed in terms of the synergistic hydrolysis of substrate， the cross-feeding of nutritional factors， and the restriction of “sugar cheaters”. The application of interspecific division of labor in lignocellulose conversion， the challenges and development directions of studying interspecific division in microbial communities of natural lignocellulose were introduced. It will provide principles for designing the construction of a microbial community with consolidated bioprocessing to promote the efficient biotransformation of lignocellulose.
2024,43(4):41-50
, DOI: 10.13300/j.cnki.hnlkxb.2024.04.006
Abstract:
Algae and bacteria play important roles in the biogeochemical cycle，energy flows of important elements in the ecosystem.Some bacteria can have beneficial interactions with algae by promoting the growth of algae and helping algae resist stress，thereby having important impacts on the survival，competition，and physiological functions of both partners.This article reviewed the main ways of interaction，microbial communities，molecular mechanisms，and the recent applications of beneficial interactions between algae and bacteria in the treatment of environmental pollution，biomass energy，and synthetic biology to in-depth study the beneficial interactions between algae and bacteria.The studies on the beneficial interactions between algae and bacteria were prospected.It will not only play an important role in understanding the structure and function of microbial community in aquatic environments，and the mechanisms and effects of relationships among microbial species，but also provide important scientific basis for maintaining the health of ecosystems，mining and utilizing the biological resources for the benefit of humanity.
Algae and bacteria play important roles in the biogeochemical cycle，energy flows of important elements in the ecosystem.Some bacteria can have beneficial interactions with algae by promoting the growth of algae and helping algae resist stress，thereby having important impacts on the survival，competition，and physiological functions of both partners.This article reviewed the main ways of interaction，microbial communities，molecular mechanisms，and the recent applications of beneficial interactions between algae and bacteria in the treatment of environmental pollution，biomass energy，and synthetic biology to in-depth study the beneficial interactions between algae and bacteria.The studies on the beneficial interactions between algae and bacteria were prospected.It will not only play an important role in understanding the structure and function of microbial community in aquatic environments，and the mechanisms and effects of relationships among microbial species，but also provide important scientific basis for maintaining the health of ecosystems，mining and utilizing the biological resources for the benefit of humanity.
2024,43(4):51-59
, DOI: 10.13300/j.cnki.hnlkxb.2024.04.007
Abstract:
Biological soil crusts are the main cover of the soil surface in arid areas， in which the microorganisms play an important role in regulating the climate sensitivity of carbon cycling in dry areas. At present， there are still disagreements in the studies on the effects of climate warming on the microbial communities and their respiration in biological soil crusts. This article summarized the emission patterns of carbon in biological soil crusts in different experimental cycles， seasons， and types of biological soil crusts through the warming experiments of simulating climate warming to more accurately predict the carbon balance in arid areas in the future. The intrinsic reasons for the differences in carbon emissions were analyzed by combining changes in microbial abundance and organic carbon. The results showed that short-term warming （below 2 year） led to a significant decrease in the abundance of moss or lichens in the biological soil crust， thereby increasing the content of organic carbon in soil， with a synchronous increase in the emissions of net carbon depending on the content of moisture in soil. Long-term warming （greater than 5 year） reduced the sensitivity of microorganisms to temperature and humidity， and the abundance and composition of microorganisms tended to stabilize， resulting in relatively stable content of organic carbon and the emissions of net carbon. The existing results reflect the patterns of and reasons for carbon emissions in biological soil crusts， but the underlying regulatory mechanisms involved by microorganisms are still unclear. Therefore， it is necessary to focus on studying the response mechanism of the carbon metabolism of microorganisms in biological soil crusts to warming in the future. It will provide important theoretical basis for evaluating carbon balance in arid areas.
Biological soil crusts are the main cover of the soil surface in arid areas， in which the microorganisms play an important role in regulating the climate sensitivity of carbon cycling in dry areas. At present， there are still disagreements in the studies on the effects of climate warming on the microbial communities and their respiration in biological soil crusts. This article summarized the emission patterns of carbon in biological soil crusts in different experimental cycles， seasons， and types of biological soil crusts through the warming experiments of simulating climate warming to more accurately predict the carbon balance in arid areas in the future. The intrinsic reasons for the differences in carbon emissions were analyzed by combining changes in microbial abundance and organic carbon. The results showed that short-term warming （below 2 year） led to a significant decrease in the abundance of moss or lichens in the biological soil crust， thereby increasing the content of organic carbon in soil， with a synchronous increase in the emissions of net carbon depending on the content of moisture in soil. Long-term warming （greater than 5 year） reduced the sensitivity of microorganisms to temperature and humidity， and the abundance and composition of microorganisms tended to stabilize， resulting in relatively stable content of organic carbon and the emissions of net carbon. The existing results reflect the patterns of and reasons for carbon emissions in biological soil crusts， but the underlying regulatory mechanisms involved by microorganisms are still unclear. Therefore， it is necessary to focus on studying the response mechanism of the carbon metabolism of microorganisms in biological soil crusts to warming in the future. It will provide important theoretical basis for evaluating carbon balance in arid areas.
2024,43(4):60-69
, DOI: 10.13300/j.cnki.hnlkxb.2024.04.008
Abstract:
The specific predatory bacteria Bdellovibrio and like organisms （BALOs） are been highly valued due to their potential applications in agriculture， industry and medicine， especially in treating the infections caused by pathogenic bacteria with antibiotic resistance. However， many fundamental scientific issues regarding BALOs have been unclear in the past decades， which is the bottom cause why these types of bacteria have not been effectively developed and utilized yet. In recent years， significant progress has been made in the life cycle， mechanisms of predation， the distribution of resource and the diversity of BALOs， and the applications of BALOs in medicine， agriculture， and industry. Especially since the formal establishment of the phylum Bdellovibrionota in 2021， there has been an explosive growth in studies related to BALOs. This article systematically reviewed the progress on studying BALOs. It was focused on introducing the latest reports on predatory mechanisms of BALOs and other outstanding achievements to promote the understanding and further application of BALOs resources， and to guide the studies on BALOs in the future.
The specific predatory bacteria Bdellovibrio and like organisms （BALOs） are been highly valued due to their potential applications in agriculture， industry and medicine， especially in treating the infections caused by pathogenic bacteria with antibiotic resistance. However， many fundamental scientific issues regarding BALOs have been unclear in the past decades， which is the bottom cause why these types of bacteria have not been effectively developed and utilized yet. In recent years， significant progress has been made in the life cycle， mechanisms of predation， the distribution of resource and the diversity of BALOs， and the applications of BALOs in medicine， agriculture， and industry. Especially since the formal establishment of the phylum Bdellovibrionota in 2021， there has been an explosive growth in studies related to BALOs. This article systematically reviewed the progress on studying BALOs. It was focused on introducing the latest reports on predatory mechanisms of BALOs and other outstanding achievements to promote the understanding and further application of BALOs resources， and to guide the studies on BALOs in the future.
2024,43(4):70-81
, DOI: 10.13300/j.cnki.hnlkxb.2024.04.009
Abstract:
Carbon in soil is an important component of the global carbon cycle，and the processes of carbon cycling play a crucial role in regulating climate，with microorganisms being the key driving force behind carbon cycling in soil. This article reviewed the roles and mechanisms of microorganisms in the input of organic carbon in soil，formation and stabilization of organic matter in soil，the processes of decomposing and mineralizing organic matter in soil，and the effects of soil properties，climate conditions，plant factors，and human activities on microorganisms mediated carbon cycling in soil，especially the progress and theoretical updates in related studies. Microorganisms in soil can indirectly promote the photosynthesis in plant and the input of carbon in soil through its symbiosis with plants，and can directly participate in the fixation and transformation of carbon in soil. Microbial residues and their secretions play a crucial role in the formation of mineral-associated organic matter and aggregates in soil，which is beneficial for the long-term stability of organic carbon in soil. The microorganisms mediated effect of priming has a regulatory effect on the decomposition of organic matter in soil，which can affect the emissions of greenhouse gases such as CO2 and CH4 from the soil. Studies on the mechanism of microorganisms mediated processes of stabilizing the organic carbon and storing carbon in soil in the future should be strengthened and focus on the complex relationship between the structure and function of microbial community and the carbon cycling in soil，as well as their response to global changes. It will provide new insights for China to achieve its major strategic goals of “carbon peak” and “carbon neutrality” through enhancing the potential of carbon sequestration or the function of carbon sink with microbial activity.
Carbon in soil is an important component of the global carbon cycle，and the processes of carbon cycling play a crucial role in regulating climate，with microorganisms being the key driving force behind carbon cycling in soil. This article reviewed the roles and mechanisms of microorganisms in the input of organic carbon in soil，formation and stabilization of organic matter in soil，the processes of decomposing and mineralizing organic matter in soil，and the effects of soil properties，climate conditions，plant factors，and human activities on microorganisms mediated carbon cycling in soil，especially the progress and theoretical updates in related studies. Microorganisms in soil can indirectly promote the photosynthesis in plant and the input of carbon in soil through its symbiosis with plants，and can directly participate in the fixation and transformation of carbon in soil. Microbial residues and their secretions play a crucial role in the formation of mineral-associated organic matter and aggregates in soil，which is beneficial for the long-term stability of organic carbon in soil. The microorganisms mediated effect of priming has a regulatory effect on the decomposition of organic matter in soil，which can affect the emissions of greenhouse gases such as CO2 and CH4 from the soil. Studies on the mechanism of microorganisms mediated processes of stabilizing the organic carbon and storing carbon in soil in the future should be strengthened and focus on the complex relationship between the structure and function of microbial community and the carbon cycling in soil，as well as their response to global changes. It will provide new insights for China to achieve its major strategic goals of “carbon peak” and “carbon neutrality” through enhancing the potential of carbon sequestration or the function of carbon sink with microbial activity.
2024,43(4):82-93
, DOI: 10.13300/j.cnki.hnlkxb.2024.04.010
Abstract:
Prokaryotic Argonautes （pAgos） are programmable nucleases involved in cellular defense against foreign DNA invasion. In vitro， pAgos can bind to small single stranded guide nucleic acid （ssDNA/ssRNA） to recognize and cleave complementary DNA/RNA. In vivo， pAgos preferentially target multiple copies of genetic elements， bacteriophages， and plasmids， thereby inhibiting the propagation of invading nucleic acids and bacteriophage infections. Prokaryotic Argonautes （pAgos）， as an emerging class of programmable nucleases， are more flexible than the most widely used CRISPR Cas system and has shown great potential in biotechnology. Previous studies were primarily focused on the thermophilic pAgos. Nowadays， the main applications based on thermophilic pAgos include molecular diagnosis and DNA assembly in vitro. Researchers have gradually shifted their focus to pAgos from mesophilic biological sources to promote the application of Ago-based biotechnology in vivo， such as gene editing. Although genome editing has not yet been achieved by pAgos， it’s possible to develop the next generation techniques for genome-editing based on pAgos with more and more pAgos being discovered and researchers studying the catalytic mechanism of pAgos in depth. This article summarized the known representative pAgos and biotechnologies based on the development of pAgos. The challenges and potential strategies faced by the application of pAgos in prokaryotic and eukaryotic organisms were briefly analyzed.
Prokaryotic Argonautes （pAgos） are programmable nucleases involved in cellular defense against foreign DNA invasion. In vitro， pAgos can bind to small single stranded guide nucleic acid （ssDNA/ssRNA） to recognize and cleave complementary DNA/RNA. In vivo， pAgos preferentially target multiple copies of genetic elements， bacteriophages， and plasmids， thereby inhibiting the propagation of invading nucleic acids and bacteriophage infections. Prokaryotic Argonautes （pAgos）， as an emerging class of programmable nucleases， are more flexible than the most widely used CRISPR Cas system and has shown great potential in biotechnology. Previous studies were primarily focused on the thermophilic pAgos. Nowadays， the main applications based on thermophilic pAgos include molecular diagnosis and DNA assembly in vitro. Researchers have gradually shifted their focus to pAgos from mesophilic biological sources to promote the application of Ago-based biotechnology in vivo， such as gene editing. Although genome editing has not yet been achieved by pAgos， it’s possible to develop the next generation techniques for genome-editing based on pAgos with more and more pAgos being discovered and researchers studying the catalytic mechanism of pAgos in depth. This article summarized the known representative pAgos and biotechnologies based on the development of pAgos. The challenges and potential strategies faced by the application of pAgos in prokaryotic and eukaryotic organisms were briefly analyzed.
2024,43(4):94-101
, DOI: 10.13300/j.cnki.hnlkxb.2024.04.011
Abstract:
Gamma-aminobutyric acid （GABA） is a four carbon and non-protein amino acid with broad application prospects in food， agriculture， medicine， chemical and other fields. The production of GABA with microbial methods has been received increasing attention due to its advantages of mildness and sustainable development. Therefore， this article systematically introduced the methods of producing GABA， the biosynthetic pathways in organisms， and the progress in studying the microbial production of GAB to achieve an environment-friendly， convenient， and more efficient method of producing GABA that meets the strict requirements for additives in the food， pharmaceutical， and animal husbandry industries. It summarized the current level of whole-cell catalysis and de novo microbial synthesis of GABA. Researchers are committed to screening and optimizing enzymes with high efficiency and stability of catalysis， and improving the efficiency of synthesizing GABA by finely regulating the metabolic pathways of microorganisms. Studies in the future need to optimize the performance of enzymes and strains， reduce costs of production， and explore pathways for industrialized production at larger scale.
Gamma-aminobutyric acid （GABA） is a four carbon and non-protein amino acid with broad application prospects in food， agriculture， medicine， chemical and other fields. The production of GABA with microbial methods has been received increasing attention due to its advantages of mildness and sustainable development. Therefore， this article systematically introduced the methods of producing GABA， the biosynthetic pathways in organisms， and the progress in studying the microbial production of GAB to achieve an environment-friendly， convenient， and more efficient method of producing GABA that meets the strict requirements for additives in the food， pharmaceutical， and animal husbandry industries. It summarized the current level of whole-cell catalysis and de novo microbial synthesis of GABA. Researchers are committed to screening and optimizing enzymes with high efficiency and stability of catalysis， and improving the efficiency of synthesizing GABA by finely regulating the metabolic pathways of microorganisms. Studies in the future need to optimize the performance of enzymes and strains， reduce costs of production， and explore pathways for industrialized production at larger scale.
2024,43(4):102-111
, DOI: 10.13300/j.cnki.hnlkxb.2024.04.012
Abstract:
Microplastics are an emerging pollutant that poses potential environmental risks to ecosystems in soil due to the widespread use and improper treating of plastic materials. Microplastics provide new habitats for microorganisms in soil and form a unique ecosystem with the surrounding environment - the plastisphere. Artificial plastics are not easily degraded in soil environments， posing a severe and persistent ecological threat to the original environment in soil. Recent studies on the plastisphere have mainly focused on aquatic ecosystems， and understanding of the combined effects of plastisphere in soil on microorganisms， microplastics， environment in soil， and other pollutants is still very limited. This article reviewed the progress on studying ecological risks of the plastisphere as new habitats for microorganisms in soil to investigate the mechanism of the interaction between microorganisms and microplastics of plastisphere in soil and the resulting ecological effects. The selection effect of plastisphere in soil on microorganisms and the migration and transformation of microplastics， the changes of soil structure and carbon cycle in soil caused by plastisphere in soil， and the combined effect with other environmental pollutants were mainly discussed. It will provide valuable guidance for studying the plastisphere of ecosystems in soil in the future.
Microplastics are an emerging pollutant that poses potential environmental risks to ecosystems in soil due to the widespread use and improper treating of plastic materials. Microplastics provide new habitats for microorganisms in soil and form a unique ecosystem with the surrounding environment - the plastisphere. Artificial plastics are not easily degraded in soil environments， posing a severe and persistent ecological threat to the original environment in soil. Recent studies on the plastisphere have mainly focused on aquatic ecosystems， and understanding of the combined effects of plastisphere in soil on microorganisms， microplastics， environment in soil， and other pollutants is still very limited. This article reviewed the progress on studying ecological risks of the plastisphere as new habitats for microorganisms in soil to investigate the mechanism of the interaction between microorganisms and microplastics of plastisphere in soil and the resulting ecological effects. The selection effect of plastisphere in soil on microorganisms and the migration and transformation of microplastics， the changes of soil structure and carbon cycle in soil caused by plastisphere in soil， and the combined effect with other environmental pollutants were mainly discussed. It will provide valuable guidance for studying the plastisphere of ecosystems in soil in the future.
2024,43(4):112-120
, DOI: 10.13300/j.cnki.hnlkxb.2024.04.013
Abstract:
Pollution of heavy metals poses a huge threat to food security and human health， and many methods for repairing the pollution of heavy metals in farmland have been developed. The supplementation of selenium significantly reduces the absorption of heavy metals by crops， while promoting their growth in soils polluted by heavy metals. The application of selenium has become a new way to mitigate the absorption of heavy metals by crops. This article reviewed five mechanisms including the alteration of the bioavailability of heavy metals in soil， competition between selenium and heavy metals in plant uptake channels， the promotion of forming iron plaque in plant roots， the induction of morphological and structural changes in plant roots， the regulation of gene expression involved in the chelation and transport of heavy metals in plants by which selenium mitigates the absorption of heavy metals by crops. The potential risks and priorities of studying selenium in mitigating the absorption of heavy metals by crops in the future were prospected. It will provide insights and a scientific basis for the use of selenium as a highly efficient inhibitor of the absorption of heavy metals in agricultural practices.
Pollution of heavy metals poses a huge threat to food security and human health， and many methods for repairing the pollution of heavy metals in farmland have been developed. The supplementation of selenium significantly reduces the absorption of heavy metals by crops， while promoting their growth in soils polluted by heavy metals. The application of selenium has become a new way to mitigate the absorption of heavy metals by crops. This article reviewed five mechanisms including the alteration of the bioavailability of heavy metals in soil， competition between selenium and heavy metals in plant uptake channels， the promotion of forming iron plaque in plant roots， the induction of morphological and structural changes in plant roots， the regulation of gene expression involved in the chelation and transport of heavy metals in plants by which selenium mitigates the absorption of heavy metals by crops. The potential risks and priorities of studying selenium in mitigating the absorption of heavy metals by crops in the future were prospected. It will provide insights and a scientific basis for the use of selenium as a highly efficient inhibitor of the absorption of heavy metals in agricultural practices.
2024,43(4):121-132
, DOI: 10.13300/j.cnki.hnlkxb.2024.04.014
Abstract:
Strong-flavor Baijiu is one of the important types of Chinese liquor. The ethyl caproate is the characteristic flavor compound in strong-flavor Baijiu. The precursor caproic acid required for the synthesis of ethyl caproate mainly relies on the metabolism of caproic acid-producing bacteria （CPBs） during the process of fermentation. Studies on the isolation， identification and metabolic functions of CPBs have become one of the hotspots in improving the quality of Baijiu. This article reviewed the isolation of CPBs from pit mud. Three types of CPBs commonly used in the fermentation system of strong-flavor Baijiu and the pathway of synthesizing caproic acid were introduced. The effects of pH and the composition of substrate on the yield of caproic acid were discussed. The impacts of other microorganisms in the microbial community on CPBs were introduced as well. It will provide a theoretical basis for improving the quality of strong-flavor by investigating the mechanism and affecting factors of producing caproic acid driven by microorganisms in the fermentation system of strong-flavor Baijiu.
Strong-flavor Baijiu is one of the important types of Chinese liquor. The ethyl caproate is the characteristic flavor compound in strong-flavor Baijiu. The precursor caproic acid required for the synthesis of ethyl caproate mainly relies on the metabolism of caproic acid-producing bacteria （CPBs） during the process of fermentation. Studies on the isolation， identification and metabolic functions of CPBs have become one of the hotspots in improving the quality of Baijiu. This article reviewed the isolation of CPBs from pit mud. Three types of CPBs commonly used in the fermentation system of strong-flavor Baijiu and the pathway of synthesizing caproic acid were introduced. The effects of pH and the composition of substrate on the yield of caproic acid were discussed. The impacts of other microorganisms in the microbial community on CPBs were introduced as well. It will provide a theoretical basis for improving the quality of strong-flavor by investigating the mechanism and affecting factors of producing caproic acid driven by microorganisms in the fermentation system of strong-flavor Baijiu.
2024,43(4):133-139
, DOI: 10.13300/j.cnki.hnlkxb.2024.04.015
Abstract:
Bioinformatics analysis， spatiotemporal expression localization， GUS staining localization and gene silencing were used to study the mechanism of SBT family proteins in the soybean-rhizobia symbiosis to investigate the function of the GmSBT1 gene in symbiotic nitrogen fixation between rhizobia and host plants. The results showed that the GmSBT1 gene was specifically induced by rhizobia and only expressed at high levels in the nodules， possibly functioned in the rhizobia cortex and bacterial cells. RNA interference significantly reduced the fresh weight， nodule weight， and nitrogenase activity aboveground. It is indicated that the GmSBT1 protein plays an important role in the formation and development of nodules， and the nitrogen fixation in nodules as well.
Bioinformatics analysis， spatiotemporal expression localization， GUS staining localization and gene silencing were used to study the mechanism of SBT family proteins in the soybean-rhizobia symbiosis to investigate the function of the GmSBT1 gene in symbiotic nitrogen fixation between rhizobia and host plants. The results showed that the GmSBT1 gene was specifically induced by rhizobia and only expressed at high levels in the nodules， possibly functioned in the rhizobia cortex and bacterial cells. RNA interference significantly reduced the fresh weight， nodule weight， and nitrogenase activity aboveground. It is indicated that the GmSBT1 protein plays an important role in the formation and development of nodules， and the nitrogen fixation in nodules as well.
2024,43(4):140-149
, DOI: 10.13300/j.cnki.hnlkxb.2024.04.016
Abstract:
A pot culture method with vermiculite mixed soil as substrate under greenhouse conditions was used to study the effects of single or double inoculation of rhizobia and arbuscular mycorrhizal fungi on the growth of 10 soybean lines planted in most regions of China to investigate the dual inoculation effect of arbuscular mycorrhizal fungi （AMF） and soybean rhizobia and their matching with different soybean lines. The results showed that both rhizobium Bradyrhizobium japonicum USDA110 and mycorrhizal fungus Rhizophagus irregularis infected 10 lines of soybean plants， forming a symbiotic structure. Single inoculation of rhizobia or mycorrhizal fungi significantly increased the aboveground fresh weight of soybean. Among them， single inoculation of rhizobia increased the aboveground fresh weight of soybean line 119， 851， and 921 by 102% to 429%， and single inoculation of mycorrhizal fungi increased the aboveground fresh weight of most soybean lines by 39% to 255%. The symbiotic colonization of mycorrhizal fungi showed a delayed phenomenon under the dual inoculation conditions of rhizobia and mycorrhizal fungi. The single nodule volume of soybean line 985， 851， and 115 increased， and the nitrogenase activity was enhanced when mycorrhizal fungi were present. Therefore， the same inoculation method had different effects on different lines of soybeans， and the same line of soybeans had differences in growth after being treated with different inoculation methods. Soybean line 985 and 115 had the best effect with dual inoculation method， soybean line 167， 509， 921， and 187 had the best effect with single inoculation method， while single inoculation of rhizobia or mycorrhizal fungi in soybean line 119， 909， and 045 can be used to increase yield.
A pot culture method with vermiculite mixed soil as substrate under greenhouse conditions was used to study the effects of single or double inoculation of rhizobia and arbuscular mycorrhizal fungi on the growth of 10 soybean lines planted in most regions of China to investigate the dual inoculation effect of arbuscular mycorrhizal fungi （AMF） and soybean rhizobia and their matching with different soybean lines. The results showed that both rhizobium Bradyrhizobium japonicum USDA110 and mycorrhizal fungus Rhizophagus irregularis infected 10 lines of soybean plants， forming a symbiotic structure. Single inoculation of rhizobia or mycorrhizal fungi significantly increased the aboveground fresh weight of soybean. Among them， single inoculation of rhizobia increased the aboveground fresh weight of soybean line 119， 851， and 921 by 102% to 429%， and single inoculation of mycorrhizal fungi increased the aboveground fresh weight of most soybean lines by 39% to 255%. The symbiotic colonization of mycorrhizal fungi showed a delayed phenomenon under the dual inoculation conditions of rhizobia and mycorrhizal fungi. The single nodule volume of soybean line 985， 851， and 115 increased， and the nitrogenase activity was enhanced when mycorrhizal fungi were present. Therefore， the same inoculation method had different effects on different lines of soybeans， and the same line of soybeans had differences in growth after being treated with different inoculation methods. Soybean line 985 and 115 had the best effect with dual inoculation method， soybean line 167， 509， 921， and 187 had the best effect with single inoculation method， while single inoculation of rhizobia or mycorrhizal fungi in soybean line 119， 909， and 045 can be used to increase yield.
2024,43(4):150-158
, DOI: 10.13300/j.cnki.hnlkxb.2024.04.017
Abstract:
Antibiotics and heavy metals are persistent pollutants in the environment， and the assessment of their toxicity to organisms has always been a hotspot of study. This article investigated the effects of single and combined pollution of tetracycline/sulfamethoxazole and cadmium ions on the growth of Synechocystis sp. PCC6803. The results showed that a single exposure to 100 ng/L sulfamethoxazole（SMX） stimulated the growth and photosynthetic activity of Synechocystis， whereas treatment with tetracycline（TC） had no significant effect. Cadmium ions（Cd2+） at 0.001 mg/L did not significantly affect the physiology of Synechocystis， but Cd2+ at 0.5 mg/L significantly inhibited the growth and photosynthesis of Synechocystis. This concentration downregulated photosynthesis-related gene（psbA2）， disrupted the antioxidant system of Synechocystis， damaged its cell membranes， and stimulated the secretion of its extracellular polysaccharides. When 100 ng/L TC coexisted with 0.001 mg/L Cd2+ synergistically， the cellular esterase activity was stimulated. 100 ng/L SMX alleviated oxidative damage caused by 0.5 mg/L Cd2+， resulting in the reduced production of reactive oxygen species（ROS）， the decreased activity of superoxide dismutase（SOD）， and the low content of malonaldehyde（MDA） compared to the group treated by single 0.5 mg/L Cd2+. When both were present simultaneously， they synergistically stimulated the activity of esterase in Synechocystis. Low concentrations of tetracycline had minimal impact on cell growth and did not significantly alter the cytotoxicity of Cd2+ on cells. In contrast， low concentrations of sulfamethoxazole promoted cell growth and mitigated the cytotoxic effects of Cd2+ on cells. It is indicated that it is necessary to comprehensively consider the combined pollution of antibiotics and heavy metals when pollution is assessed.
Antibiotics and heavy metals are persistent pollutants in the environment， and the assessment of their toxicity to organisms has always been a hotspot of study. This article investigated the effects of single and combined pollution of tetracycline/sulfamethoxazole and cadmium ions on the growth of Synechocystis sp. PCC6803. The results showed that a single exposure to 100 ng/L sulfamethoxazole（SMX） stimulated the growth and photosynthetic activity of Synechocystis， whereas treatment with tetracycline（TC） had no significant effect. Cadmium ions（Cd2+） at 0.001 mg/L did not significantly affect the physiology of Synechocystis， but Cd2+ at 0.5 mg/L significantly inhibited the growth and photosynthesis of Synechocystis. This concentration downregulated photosynthesis-related gene（psbA2）， disrupted the antioxidant system of Synechocystis， damaged its cell membranes， and stimulated the secretion of its extracellular polysaccharides. When 100 ng/L TC coexisted with 0.001 mg/L Cd2+ synergistically， the cellular esterase activity was stimulated. 100 ng/L SMX alleviated oxidative damage caused by 0.5 mg/L Cd2+， resulting in the reduced production of reactive oxygen species（ROS）， the decreased activity of superoxide dismutase（SOD）， and the low content of malonaldehyde（MDA） compared to the group treated by single 0.5 mg/L Cd2+. When both were present simultaneously， they synergistically stimulated the activity of esterase in Synechocystis. Low concentrations of tetracycline had minimal impact on cell growth and did not significantly alter the cytotoxicity of Cd2+ on cells. In contrast， low concentrations of sulfamethoxazole promoted cell growth and mitigated the cytotoxic effects of Cd2+ on cells. It is indicated that it is necessary to comprehensively consider the combined pollution of antibiotics and heavy metals when pollution is assessed.
2024,43(4):159-168
, DOI: 10.13300/j.cnki.hnlkxb.2024.04.018
Abstract:
Integrated fertilizer management（IFM） with a higher N dose and more fertilizer splits has been designed to increase rice yield for the full double rice system instead of for farmers in the subtropical regions of China.Higher levels of chemical fertilizers negatively affect the environment and microbial ecology， but more splits to meet plant demand might reduce adverse effects and promote soil function.A field experiment for double rice cropping conducted in 2013-2014 was used to study whether integrated fertilizer management has beneficial effects on the microbial community and microbial function compared with conventional practices of farmers（FP）.A randomized block including integrated fertilizer management（IFM） and conventional practices of farmers（FPs） was designed.Rhizosphere and non-rhizosphere soils were collected at three time points during the season of growing late rice to investigate the chemical properties and enzyme activity in soil.The phospholipid fatty acids（PLFA） were used to identify microbial biomass and community composition.The results showed that IFM treatment reduced the ratio of Gram-positive bacteria（GP） to Gram-negative bacteria（GN） and the index of microbial stress in rhizosphere soil compared with the FP treatment.IFM promoted the activity of sucrase， acid phosphatase， and arylsulfatase in the rhizosphere soil at the stage of panicle differentiation and full-heading， while inhibiting the activity of urease at the stage of maturity.The results of analyzing redundancy showed that available nitrogen and total nitrogen explained 15.9% and 12.5% of the variability in the microbial community and enzyme activities， indicating that N availability and its level play key roles in regulating the microbial community and enzyme functions in paddy soil.The enzyme activity was significantly explained by Gram-negative bacteria（GN，5.39%）， fungi（3.88%） and AM fungi（3.09%）.The index of microbial stress was negatively correlated with the activity of phosphatase and sucrase， indicating that both bacteria and fungi are involved in the regulation of enzyme activity in soil.It is indicated that IFM mainly regulates the rhythm of nitrogen incorporation in paddy soil to change the composition of microbial communities， thereby enhancing enzyme activity in soil before maturity and promoting nutrient cycling during the growth of rice.
Integrated fertilizer management（IFM） with a higher N dose and more fertilizer splits has been designed to increase rice yield for the full double rice system instead of for farmers in the subtropical regions of China.Higher levels of chemical fertilizers negatively affect the environment and microbial ecology， but more splits to meet plant demand might reduce adverse effects and promote soil function.A field experiment for double rice cropping conducted in 2013-2014 was used to study whether integrated fertilizer management has beneficial effects on the microbial community and microbial function compared with conventional practices of farmers（FP）.A randomized block including integrated fertilizer management（IFM） and conventional practices of farmers（FPs） was designed.Rhizosphere and non-rhizosphere soils were collected at three time points during the season of growing late rice to investigate the chemical properties and enzyme activity in soil.The phospholipid fatty acids（PLFA） were used to identify microbial biomass and community composition.The results showed that IFM treatment reduced the ratio of Gram-positive bacteria（GP） to Gram-negative bacteria（GN） and the index of microbial stress in rhizosphere soil compared with the FP treatment.IFM promoted the activity of sucrase， acid phosphatase， and arylsulfatase in the rhizosphere soil at the stage of panicle differentiation and full-heading， while inhibiting the activity of urease at the stage of maturity.The results of analyzing redundancy showed that available nitrogen and total nitrogen explained 15.9% and 12.5% of the variability in the microbial community and enzyme activities， indicating that N availability and its level play key roles in regulating the microbial community and enzyme functions in paddy soil.The enzyme activity was significantly explained by Gram-negative bacteria（GN，5.39%）， fungi（3.88%） and AM fungi（3.09%）.The index of microbial stress was negatively correlated with the activity of phosphatase and sucrase， indicating that both bacteria and fungi are involved in the regulation of enzyme activity in soil.It is indicated that IFM mainly regulates the rhythm of nitrogen incorporation in paddy soil to change the composition of microbial communities， thereby enhancing enzyme activity in soil before maturity and promoting nutrient cycling during the growth of rice.
2024,43(4):169-181
, DOI: 10.13300/j.cnki.hnlkxb.2024.04.019
Abstract:
FeOB were enriched with modified wolf’s mineral medium （MWMM） to screen microaerobic Fe2+ oxidizing bacteria （FeOB） with better oxidative abilities to Fe2+，evaluate its effects on improving soil and the microbial communities and functions of soil in gleyed paddy field，and lay a foundation for establishing technologies of improving microorganism in gleyed paddy fields.The FeOB strain was taxonomically identified with combined technologies including 16S rRNA sequencing.The 100 mL fermentation liquid of the strain with different concentration of 106 （T1），107 （T2），108 （T3） CFU/mL was used to treat the soil in gleyed paddy field and evaluate the effects of the strain on the reducing substances，nutrients，abundances of functional genes for nitrogen cycling （NCFG） and rice seedlings of soil in gleyed paddy field.16S rRNA high-throughput sequencing technology was used to evaluate the effect of this strain on the soil microecology.The results showed that the FeOB strain screened with strong oxidative effect on Fe2+ was identified as Lysinibacillus sphaericus WH07.Compared to CK，the soil redox potential （Eh） was significantly increased （P<0.05） and shifted from negative potential to positive potential.The total amount of reducing substance in soil treated with T1，T2，and T3 decreased by 26.47%，41.53%，and 53.19%，respectively.The content of ferrous decreased by 0.37%，21.50%，and 50.09%，while the content of manganese decreased by 7.84%，21.57%，and 37.25%.The content of alkaline hydrolyzed nitrogen in soil significantly increased by 15.50%，27.38%，and 48.90% （P<0.05），while the available phosphorus significantly increased by 12.52%，17.34%，and 27.38% （P<0.05）.The available potassium significantly increased by 11.56%，17.20%，and 19.34% （P<0.05），and the organic matter significantly increased by 8.66%，22.22%，and 45.05% （P<0.05）.The pH significantly increased by 3.40%，8.94%，and 16.99% （P<0.05）.The abundance of AOA-amoA gene in soil increased by 11.94%，14.68%，and 33.83%，respectively.The abundance of nosZ gene increased by 42.97%，75.78%，and 118.75%，while the abundance of nifH gene increased by 38.29%，51.05%，and 216.13%.The abundance of UreC gene increased by 16.74%，54.51%，and 60.94%.The plant height of rice increased by 5.44%，10.98%，36.00%，the leaf age of rice increased by 10.21%，23.42%，36.94%，the fresh weight of rice increased by 12.61%，22.52%，28.38%，and the white root number of rice increased by 10.14%，32.92%，and 46.81%.The Chao1 and Shannon index of microbial diversity in soil was significantly decreased compared to CK （P<0.05）.Among the top 10 bacteria in soil with relative abundance at the Phylum level，8 phyla including Proteobacteria were significantly downregulated （P<0.05），while 2 phyla including Bacteroidetes and Firmicutes were significantly upregulated.Among the top 10 bacteria in soil with relative abundance at the Phylum level，8 phyla including Proteobacteria were significantly downregulated （P<0.05），while 2 phyla including Bacteroidetes and Firmicutes were significantly upregulated.Among the top 50 bacteria in soil with relative abundance at the genus level，20，19，and 22 genera including 6 FeOBs such as Macellibacteroides et al were significantly upregulated （P<0.05） in the three treatments，while 25 genera including 4 Fe reducing bacteria such as MBNT15 et al were significantly down-regulated in all three treatments （P<0.05）.The results of analyzing regulatory network showed that the strain WH07 had the potential to synergistically improve the physicochemical properties and biological activity of soil with FeOB，ultimately promoting the growth of rice seedlings.It is indicated that the application of strain WH07 significantly improves the physicochemical properties of soil in the gleyed paddy field and change the structure and function of microbial community in soil.
FeOB were enriched with modified wolf’s mineral medium （MWMM） to screen microaerobic Fe2+ oxidizing bacteria （FeOB） with better oxidative abilities to Fe2+，evaluate its effects on improving soil and the microbial communities and functions of soil in gleyed paddy field，and lay a foundation for establishing technologies of improving microorganism in gleyed paddy fields.The FeOB strain was taxonomically identified with combined technologies including 16S rRNA sequencing.The 100 mL fermentation liquid of the strain with different concentration of 106 （T1），107 （T2），108 （T3） CFU/mL was used to treat the soil in gleyed paddy field and evaluate the effects of the strain on the reducing substances，nutrients，abundances of functional genes for nitrogen cycling （NCFG） and rice seedlings of soil in gleyed paddy field.16S rRNA high-throughput sequencing technology was used to evaluate the effect of this strain on the soil microecology.The results showed that the FeOB strain screened with strong oxidative effect on Fe2+ was identified as Lysinibacillus sphaericus WH07.Compared to CK，the soil redox potential （Eh） was significantly increased （P<0.05） and shifted from negative potential to positive potential.The total amount of reducing substance in soil treated with T1，T2，and T3 decreased by 26.47%，41.53%，and 53.19%，respectively.The content of ferrous decreased by 0.37%，21.50%，and 50.09%，while the content of manganese decreased by 7.84%，21.57%，and 37.25%.The content of alkaline hydrolyzed nitrogen in soil significantly increased by 15.50%，27.38%，and 48.90% （P<0.05），while the available phosphorus significantly increased by 12.52%，17.34%，and 27.38% （P<0.05）.The available potassium significantly increased by 11.56%，17.20%，and 19.34% （P<0.05），and the organic matter significantly increased by 8.66%，22.22%，and 45.05% （P<0.05）.The pH significantly increased by 3.40%，8.94%，and 16.99% （P<0.05）.The abundance of AOA-amoA gene in soil increased by 11.94%，14.68%，and 33.83%，respectively.The abundance of nosZ gene increased by 42.97%，75.78%，and 118.75%，while the abundance of nifH gene increased by 38.29%，51.05%，and 216.13%.The abundance of UreC gene increased by 16.74%，54.51%，and 60.94%.The plant height of rice increased by 5.44%，10.98%，36.00%，the leaf age of rice increased by 10.21%，23.42%，36.94%，the fresh weight of rice increased by 12.61%，22.52%，28.38%，and the white root number of rice increased by 10.14%，32.92%，and 46.81%.The Chao1 and Shannon index of microbial diversity in soil was significantly decreased compared to CK （P<0.05）.Among the top 10 bacteria in soil with relative abundance at the Phylum level，8 phyla including Proteobacteria were significantly downregulated （P<0.05），while 2 phyla including Bacteroidetes and Firmicutes were significantly upregulated.Among the top 10 bacteria in soil with relative abundance at the Phylum level，8 phyla including Proteobacteria were significantly downregulated （P<0.05），while 2 phyla including Bacteroidetes and Firmicutes were significantly upregulated.Among the top 50 bacteria in soil with relative abundance at the genus level，20，19，and 22 genera including 6 FeOBs such as Macellibacteroides et al were significantly upregulated （P<0.05） in the three treatments，while 25 genera including 4 Fe reducing bacteria such as MBNT15 et al were significantly down-regulated in all three treatments （P<0.05）.The results of analyzing regulatory network showed that the strain WH07 had the potential to synergistically improve the physicochemical properties and biological activity of soil with FeOB，ultimately promoting the growth of rice seedlings.It is indicated that the application of strain WH07 significantly improves the physicochemical properties of soil in the gleyed paddy field and change the structure and function of microbial community in soil.
ZHENG Meiying, LIU Futong, ZHENG Bangxi, HUANG Zhihong, XU Huaqing, ZHANG Ya'nan, HE Wenqin, YAO Feng, REN Tianbao
2024,43(4):182-191
, DOI: 10.13300/j.cnki.hnlkxb.2024.04.020
Abstract:
The changes in the physicochemical properties， the diversity of microorganisms and the structure of microbial community in the soil planted continuously with flue-cured tobaccos of different planting years including continuous cropping for 0 year （CK）， continuous cropping for 2 years （T1）， continuous cropping for 4 years （T2）， continuous cropping for 6 years （T3）， and continuous cropping for 8 years （T4） in Hanzhong area of Shaanxi Province were analyzed to study the key factors affecting the obstacles for continuous cropping of flue-cured tobacco and its patterns. The results showed that the organic matter， pH， and the content of total carbon in soil decreased with the increasing years of planting. The organic matter， pH， and the content of total carbon in the soil of T4 was 8.34%， 25.39%， and 25.20% lower than that of CK. The diversity and abundance of bacteria and fungi in soil showed a trend of increasing first and then decreasing， with the dominant bacterial phyla being Actinobacteriota， Proteobacteria， Acidobacteriota， Chloroflexi and Firmicutes. The dominant fungal phyla were Ascomycota， Basidiomycota， and Mucoromycota. Compared with CK， the relative abundance of microorganisms under T3 changed significantly， with change in Actinobacteria， Firmicutes， and Basidiomycota of 4.04%， 6.24%， and 28.86%， respectively. It is indicated that continuous cropping of flue-cured tobaccos reduces the content of organic matter， pH， and the content of total carbon in soil， affecting the composition of microbial community in soil.
The changes in the physicochemical properties， the diversity of microorganisms and the structure of microbial community in the soil planted continuously with flue-cured tobaccos of different planting years including continuous cropping for 0 year （CK）， continuous cropping for 2 years （T1）， continuous cropping for 4 years （T2）， continuous cropping for 6 years （T3）， and continuous cropping for 8 years （T4） in Hanzhong area of Shaanxi Province were analyzed to study the key factors affecting the obstacles for continuous cropping of flue-cured tobacco and its patterns. The results showed that the organic matter， pH， and the content of total carbon in soil decreased with the increasing years of planting. The organic matter， pH， and the content of total carbon in the soil of T4 was 8.34%， 25.39%， and 25.20% lower than that of CK. The diversity and abundance of bacteria and fungi in soil showed a trend of increasing first and then decreasing， with the dominant bacterial phyla being Actinobacteriota， Proteobacteria， Acidobacteriota， Chloroflexi and Firmicutes. The dominant fungal phyla were Ascomycota， Basidiomycota， and Mucoromycota. Compared with CK， the relative abundance of microorganisms under T3 changed significantly， with change in Actinobacteria， Firmicutes， and Basidiomycota of 4.04%， 6.24%， and 28.86%， respectively. It is indicated that continuous cropping of flue-cured tobaccos reduces the content of organic matter， pH， and the content of total carbon in soil， affecting the composition of microbial community in soil.
2024,43(4):192-203
, DOI: 10.13300/j.cnki.hnlkxb.2024.04.021
Abstract:
The dilution coating plate method was used to isolate and screen a salt-tolerant strain SF-18 with significant antibacterial activity from soil samples in Aksu saline alkali land，Xinjiang to obtain biocontrol agents with elite antibacterial activity from extreme environments. The stability of the antagonistic activity of the supernatant of strain SF-18 cell-free fermentation was determined using the Oxford Cup method，with the Verticillium dahliae as an indicator strain. The whole genome of strain SF-18 was sequenced with Illumina Novaseq platform and PacBio sequel platform. Data sequenced were used to assembly gene，annotate the function of gene，and predict gene clusters involved in synthesizing secondary metabolites. The results showed that strain SF-18 had a significant inhibitory effect on Staphylococcus aureus and Verticillium dahliae，and grew in the broth containing 18% NaCl. The supernatant of strain SF-18 cell-free fermentation had strong antibacterial activity at -20-80 ℃ and tolerated pH 5-12 environments. The strain SF-18 was identified as belonging to the genus Bacillus based on analyzing the sequence of 16S rDNA gene and gyrB gene. The results of whole genome analysis showed that there were 480 genes of strain SF-18 involved in the metabolism of multiple carbon sources，including genes encoding compounds related to stress resistance such as spermidine and trehalose，and genes related to enzymes such as glucanase and chitinase that can hydrolyze the cell wall of pathogen. The results of predicting secondary metabolites showed that strain SF-18 contained gene clusters involved in synthesizing a various of resistant compounds including bacillaene，bacillibactin，mersacidin，fengycin，zwittermicin. It is speculated that strain SF-18 may achieve antibacterial effects by producing antibacterial secondary metabolites and related degradation enzymes，and has good application prospects in biological control of agriculture.
The dilution coating plate method was used to isolate and screen a salt-tolerant strain SF-18 with significant antibacterial activity from soil samples in Aksu saline alkali land，Xinjiang to obtain biocontrol agents with elite antibacterial activity from extreme environments. The stability of the antagonistic activity of the supernatant of strain SF-18 cell-free fermentation was determined using the Oxford Cup method，with the Verticillium dahliae as an indicator strain. The whole genome of strain SF-18 was sequenced with Illumina Novaseq platform and PacBio sequel platform. Data sequenced were used to assembly gene，annotate the function of gene，and predict gene clusters involved in synthesizing secondary metabolites. The results showed that strain SF-18 had a significant inhibitory effect on Staphylococcus aureus and Verticillium dahliae，and grew in the broth containing 18% NaCl. The supernatant of strain SF-18 cell-free fermentation had strong antibacterial activity at -20-80 ℃ and tolerated pH 5-12 environments. The strain SF-18 was identified as belonging to the genus Bacillus based on analyzing the sequence of 16S rDNA gene and gyrB gene. The results of whole genome analysis showed that there were 480 genes of strain SF-18 involved in the metabolism of multiple carbon sources，including genes encoding compounds related to stress resistance such as spermidine and trehalose，and genes related to enzymes such as glucanase and chitinase that can hydrolyze the cell wall of pathogen. The results of predicting secondary metabolites showed that strain SF-18 contained gene clusters involved in synthesizing a various of resistant compounds including bacillaene，bacillibactin，mersacidin，fengycin，zwittermicin. It is speculated that strain SF-18 may achieve antibacterial effects by producing antibacterial secondary metabolites and related degradation enzymes，and has good application prospects in biological control of agriculture.
2024,43(4):204-211
, DOI: 10.13300/j.cnki.hnlkxb.2024.04.022
Abstract:
Three genera of myxobacteria including Corallococcus sp. EGB， Myxococcus xanthus DK1622 and Cystobacter sp. 1404 were used to study the physiological function of thiamine I from myxobacteria. The relationship between the pathway of synthesizing thiamine and the growth and development of strain in the genomes of three myxobacteria was identified. The results showed that three myxobacteria had complete pathway of synthesizing thiamine in their genomes， and contained genes related to the recovery of thiamine precursor pyrimidine （4-amino-5-hydroxymethyl-2-methylpyrimidine， HMP）， but no genes related to the recovery of thiamine or its precursor thiazole was found. The presence of TPP-riboswitch at the upstream of the HMP synthase gene thiC regulated the transcription level of the thiC gene based on the concentration of thiamine in the environment. Mutant CL1006 and Mutant CL1007 were constructed by inserting the thiC gene into strain DK1622 and thiaminase I knockout mutant CL1003， respectively. It was found that CL1006 required additional addition of thiamine or HMP to recover growth in thiamine-free medium. The HMP treatment group significantly increased the colony diameter by 9.0% compared to the thiamine-treated group. CL1007 only grew on HMP plates， and the addition of intact thiamine alone did not restore its growth. However， when CcThi1 and thiamine were added together， the growth of CL1007 was restored. It is indicated that myxobacteria do not directly utilize exogenous thiamine， but can utilize pyrimidine precursors produced by decomposing thiamine through thiaminase I.
Three genera of myxobacteria including Corallococcus sp. EGB， Myxococcus xanthus DK1622 and Cystobacter sp. 1404 were used to study the physiological function of thiamine I from myxobacteria. The relationship between the pathway of synthesizing thiamine and the growth and development of strain in the genomes of three myxobacteria was identified. The results showed that three myxobacteria had complete pathway of synthesizing thiamine in their genomes， and contained genes related to the recovery of thiamine precursor pyrimidine （4-amino-5-hydroxymethyl-2-methylpyrimidine， HMP）， but no genes related to the recovery of thiamine or its precursor thiazole was found. The presence of TPP-riboswitch at the upstream of the HMP synthase gene thiC regulated the transcription level of the thiC gene based on the concentration of thiamine in the environment. Mutant CL1006 and Mutant CL1007 were constructed by inserting the thiC gene into strain DK1622 and thiaminase I knockout mutant CL1003， respectively. It was found that CL1006 required additional addition of thiamine or HMP to recover growth in thiamine-free medium. The HMP treatment group significantly increased the colony diameter by 9.0% compared to the thiamine-treated group. CL1007 only grew on HMP plates， and the addition of intact thiamine alone did not restore its growth. However， when CcThi1 and thiamine were added together， the growth of CL1007 was restored. It is indicated that myxobacteria do not directly utilize exogenous thiamine， but can utilize pyrimidine precursors produced by decomposing thiamine through thiaminase I.
2024,43(4):212-220
, DOI: 10.13300/j.cnki.hnlkxb.2024.04.023
Abstract:
Enterobacter sp.A11 and Comamonas sp.A23 with the ability to oxidize Fe and Mn compounds was used to study the feasible methods for co-removing the cadmium （Cd） and arsenic （As） in soil.The effects of the biological Fe and Mn oxides （BFMO） generated by the mixed strains of A11 and A23 on the absorption of cadmium and arsenic in B. rapa. The results of scanning electron microscopy （SEM） showed that iron and manganese oxides were located on the surface of cells and led bacteria to aggregate into clusters.The results of pot experiment showed that strains A11 and A23 immobilized Cd and As in soil，reduced the proportion of bioavailable Cd and As，increased the proportion of unavailable Cd and As，and exhibited the absorption and accumulation of Cd and As in the aboveground and root parts of Brassica rapa L. as well.It is indicated that the biological iron manganese oxide generated by the mixed strains of A11 and A23 has a good adsorption effect on cadmium and arsenic in B. rapa.
Enterobacter sp.A11 and Comamonas sp.A23 with the ability to oxidize Fe and Mn compounds was used to study the feasible methods for co-removing the cadmium （Cd） and arsenic （As） in soil.The effects of the biological Fe and Mn oxides （BFMO） generated by the mixed strains of A11 and A23 on the absorption of cadmium and arsenic in B. rapa. The results of scanning electron microscopy （SEM） showed that iron and manganese oxides were located on the surface of cells and led bacteria to aggregate into clusters.The results of pot experiment showed that strains A11 and A23 immobilized Cd and As in soil，reduced the proportion of bioavailable Cd and As，increased the proportion of unavailable Cd and As，and exhibited the absorption and accumulation of Cd and As in the aboveground and root parts of Brassica rapa L. as well.It is indicated that the biological iron manganese oxide generated by the mixed strains of A11 and A23 has a good adsorption effect on cadmium and arsenic in B. rapa.
2024,43(4):221-229
, DOI: 10.13300/j.cnki.hnlkxb.2024.04.024
Abstract:
The wet heartwood and normal wood of 6-year-old Populus deltoides Bartr. ‘Huashi2’ in the Jianghan Plain were used to study the role of bacterial and microbial communities in the pathogenesis in the wet heartwood of Populus. High-throughput sequencing was used to sequence the V5-V7 region of the 16S rRNA gene. The results of sequencing were analyzed with bioinformatics. Methods including principal component analysis， α-diversity index analysis， and microbial network analysis were used to study the differences in the structure and composition of the bacterial and microbial communities in the wet heartwood and normal wood of 6-year-old Populus deltoides Bartr. The results of principal component analysis showed that the bacterial abundance of the genera Ralstonia and Bacteroides was the highest， while the proportion of the genera Bacteroides， Pleomorphomonas and Hydrogenispora in wet heartwood was significantly higher than that in normal wood （P<0.05） at the genus level of the bacterial and microbial communities in the wet heartwood and normal wood of 6-year-old Populus deltoides Bartr. The results of analyzing the functions of microbial communities showed that Ralstonia were mostly phytopathogenic bacteria， which widely existed in wet heartwood. The results of analyzing the alpha diversity index showed that the diversity and species distribution uniformity of the community in the wet heartwood were higher than those in the normal wood， and the total number of species in the wet heartwood was lower than that in the normal wood. The results of analyzing the co-occurrence network showed that there was a lot of competition and antagonism between bacteria and microorganisms in the normal wood of Populus deltoides Bartr， and the community was relatively unstable. There were more synergistic and mutualistic relationships among bacteria in wet heartwood， and the microbial community was relatively stable. The results of analyzing key microorganisms showed that the key bacterial microorganisms in the wet heartwood of 6-year-old Populus deltoides Bartr. were Aquabacterium， WCHB1-32， etc.， and the key bacterial microorganisms in the normal heartwood of 6-year-old Populus deltoides Bartr. were Pleomorphomonas， Dysgonomonas， etc. These key microorganisms played an important role in stabilizing the structure of microbial network in the wet heartwood. It is indicated that the formation of wet heartwood in Populus deltoides Bartr. is affected by multiple factors and is the result of the joint action of microbial communities.
The wet heartwood and normal wood of 6-year-old Populus deltoides Bartr. ‘Huashi2’ in the Jianghan Plain were used to study the role of bacterial and microbial communities in the pathogenesis in the wet heartwood of Populus. High-throughput sequencing was used to sequence the V5-V7 region of the 16S rRNA gene. The results of sequencing were analyzed with bioinformatics. Methods including principal component analysis， α-diversity index analysis， and microbial network analysis were used to study the differences in the structure and composition of the bacterial and microbial communities in the wet heartwood and normal wood of 6-year-old Populus deltoides Bartr. The results of principal component analysis showed that the bacterial abundance of the genera Ralstonia and Bacteroides was the highest， while the proportion of the genera Bacteroides， Pleomorphomonas and Hydrogenispora in wet heartwood was significantly higher than that in normal wood （P<0.05） at the genus level of the bacterial and microbial communities in the wet heartwood and normal wood of 6-year-old Populus deltoides Bartr. The results of analyzing the functions of microbial communities showed that Ralstonia were mostly phytopathogenic bacteria， which widely existed in wet heartwood. The results of analyzing the alpha diversity index showed that the diversity and species distribution uniformity of the community in the wet heartwood were higher than those in the normal wood， and the total number of species in the wet heartwood was lower than that in the normal wood. The results of analyzing the co-occurrence network showed that there was a lot of competition and antagonism between bacteria and microorganisms in the normal wood of Populus deltoides Bartr， and the community was relatively unstable. There were more synergistic and mutualistic relationships among bacteria in wet heartwood， and the microbial community was relatively stable. The results of analyzing key microorganisms showed that the key bacterial microorganisms in the wet heartwood of 6-year-old Populus deltoides Bartr. were Aquabacterium， WCHB1-32， etc.， and the key bacterial microorganisms in the normal heartwood of 6-year-old Populus deltoides Bartr. were Pleomorphomonas， Dysgonomonas， etc. These key microorganisms played an important role in stabilizing the structure of microbial network in the wet heartwood. It is indicated that the formation of wet heartwood in Populus deltoides Bartr. is affected by multiple factors and is the result of the joint action of microbial communities.
2024,43(4):230-238
, DOI: 10.13300/j.cnki.hnlkxb.2024.04.025
Abstract:
Poria cocos was cultured on the solid medium using Lentinula edodes stalk as the sole substrate to study whether the mycelia of P. cocos can ferment and utilize L. edodes stalk substrate and improve its nutritional value and biological activity. The activity of key enzymes， the components of main nutrient， and the antioxidant activity of water extracts from the fermented substrate during solid-state fermentation of P. cocos were measured. The results showed that the activity of cellulose exonuclease reached 46.14 U/g at the 6th day of fermentation， then rapidly decreased to 17.15 U/g， and remained basically unchanged at the 18th day of fermentation as the process of fermentation progressed. The activity of carboxymethyl cellulase and xylanase reached 77.70 U/g and 74.23 U/g at the 12th day of fermentation， and then gradually decreased. The activity of β-glucosidase reached 75.06 U/g at the 18th day of the fermentation and then gradually decreased. Compared with the unfermented L. edodes stalk substrate， the content of total sugar， soluble protein， and insoluble dietary fiber in the fermented L. edodes stalk substrate significantly decreased， but the content of reducing sugar， polysaccharides， total phenols， total flavone， amino nitrogen， and soluble dietary fiber significantly increased. The antioxidant activity of water extracts from the fermented substrate was significantly increased. The scavenging rate of DPPH radical and hydroxyl radical increased by 97.75% and 38.15%， compared to the 0 day of fermentation. It is indicated that P. cocos can ferment L. edodes stalk， alter the composition of nutrient in L. edodes stalks， and that the fermented substrate has good ability to scavenge free radicals.
Poria cocos was cultured on the solid medium using Lentinula edodes stalk as the sole substrate to study whether the mycelia of P. cocos can ferment and utilize L. edodes stalk substrate and improve its nutritional value and biological activity. The activity of key enzymes， the components of main nutrient， and the antioxidant activity of water extracts from the fermented substrate during solid-state fermentation of P. cocos were measured. The results showed that the activity of cellulose exonuclease reached 46.14 U/g at the 6th day of fermentation， then rapidly decreased to 17.15 U/g， and remained basically unchanged at the 18th day of fermentation as the process of fermentation progressed. The activity of carboxymethyl cellulase and xylanase reached 77.70 U/g and 74.23 U/g at the 12th day of fermentation， and then gradually decreased. The activity of β-glucosidase reached 75.06 U/g at the 18th day of the fermentation and then gradually decreased. Compared with the unfermented L. edodes stalk substrate， the content of total sugar， soluble protein， and insoluble dietary fiber in the fermented L. edodes stalk substrate significantly decreased， but the content of reducing sugar， polysaccharides， total phenols， total flavone， amino nitrogen， and soluble dietary fiber significantly increased. The antioxidant activity of water extracts from the fermented substrate was significantly increased. The scavenging rate of DPPH radical and hydroxyl radical increased by 97.75% and 38.15%， compared to the 0 day of fermentation. It is indicated that P. cocos can ferment L. edodes stalk， alter the composition of nutrient in L. edodes stalks， and that the fermented substrate has good ability to scavenge free radicals.
2024,43(4):239-248
, DOI: 10.13300/j.cnki.hnlkxb.2024.04.026
Abstract:
Traditional high-temperature Daqu is produced by spontaneous fermentation， which has disadvantages including complex composition of microbial community and difficulty in controlling the components and content of required flavor. Wheat was used to prepare the solid microbial agents of Bacillus licheniformis BL44， Saccharomyces cerevisiae SCY62， Paecilomyces variotii PV3， Rhizomucor pusillus RP1 and Thermoascus crustaceus TC1 isolated and screened from the high-temperature Daqu to optimize the structure of microbial community in high-temperature Daqu and improve the quality of high-temperature Daqu. Two synthetic microbial communities were constructed with different addition ratios to replace the traditional Muqu （CK） in producing high-temperature Daqu. Brewing experiments in laboratory were conducted and analyzed. The results of high-throughput sequencing showed that the dominant fungal genus and the dominant bacterial genus of the three kinds of Daqu was Lichtheimia and Bacillus， respectively. The results of measuring the physicochemical indexes of the Daqu showed that the liquefaction and saccharification abilities of the high-temperature Daqu inoculated with the synthetic microbial communities were significantly improved compared to CK. The results of analyses with gas chromatography-mass spectrometry showed that inoculating synthetic microbial communities instead of traditional Muqu significantly increased the content of tetramethylpyrazine in Daqu and fermented grains. The content of tetramethylpyrazine in Daqu inoculated with synthetic microbial group 1 and microbial group 2 was 31.90 mg/kg and 56. 73 mg/kg， increased by 2.80 and 4.99 times compared to that of CK. In the high-temperature stacked fermentation mash， the content of tetramethylpyrazine inoculated with synthetic microbial group 1 and microbial group 2 was 0.76 mg/kg and 2.74 mg/kg， increased by 4.03 and 14.61 times compared to that of CK. It is indicated that the synthetic microbial community has potential application in directionally regulating the activity of enzymes in Daqu and the components and contents of some specific flavors in Baijiu.
Traditional high-temperature Daqu is produced by spontaneous fermentation， which has disadvantages including complex composition of microbial community and difficulty in controlling the components and content of required flavor. Wheat was used to prepare the solid microbial agents of Bacillus licheniformis BL44， Saccharomyces cerevisiae SCY62， Paecilomyces variotii PV3， Rhizomucor pusillus RP1 and Thermoascus crustaceus TC1 isolated and screened from the high-temperature Daqu to optimize the structure of microbial community in high-temperature Daqu and improve the quality of high-temperature Daqu. Two synthetic microbial communities were constructed with different addition ratios to replace the traditional Muqu （CK） in producing high-temperature Daqu. Brewing experiments in laboratory were conducted and analyzed. The results of high-throughput sequencing showed that the dominant fungal genus and the dominant bacterial genus of the three kinds of Daqu was Lichtheimia and Bacillus， respectively. The results of measuring the physicochemical indexes of the Daqu showed that the liquefaction and saccharification abilities of the high-temperature Daqu inoculated with the synthetic microbial communities were significantly improved compared to CK. The results of analyses with gas chromatography-mass spectrometry showed that inoculating synthetic microbial communities instead of traditional Muqu significantly increased the content of tetramethylpyrazine in Daqu and fermented grains. The content of tetramethylpyrazine in Daqu inoculated with synthetic microbial group 1 and microbial group 2 was 31.90 mg/kg and 56. 73 mg/kg， increased by 2.80 and 4.99 times compared to that of CK. In the high-temperature stacked fermentation mash， the content of tetramethylpyrazine inoculated with synthetic microbial group 1 and microbial group 2 was 0.76 mg/kg and 2.74 mg/kg， increased by 4.03 and 14.61 times compared to that of CK. It is indicated that the synthetic microbial community has potential application in directionally regulating the activity of enzymes in Daqu and the components and contents of some specific flavors in Baijiu.
Display Method:
Abstract:
In recent years, the spatial non-integration effect of administrative regions and economic zones existed in China, and as an important means of spatial governance, territorial spatial planning is the important foundation for the high-quality development of cross-regional. The research area is Beijing-Tianjin-Hebei agglomeration, explores the spatio-temporal change and driving mechanism of land development intensity, and embeded the adjacency relationship between county-level administrative units into the spatial econometric model to explore the influence mechanism of land development intensity under the different scenarios of administrative spatial spillover effect. The results show that the land development intensity of different county-level administrative unites were quite different in the Beijing-Tianjin-Hebei agglomeration, and the spatio-temporal differentiation and spatial agglomeration was significantly. The land development intensity of most county-level administrative units in the Beijing-Tianjin-Hebei agglomeration were improved, but the spatial pattern of "high in the southeast and low in the northwest" has not change. Population density, the proportion of tertiary industry added value and per capita GDP had significant effects on the land development intensity. The spatial distribution of land development intensity has significant positive spatial correlation, and the direct spatial spillover effect is obvious. From 2010 to 2019, the administrative spatial spillover effect of different adjacent relationships were different, and the spillover of adjacent relationships of different types of county-level administrative units was enhanced. In the future , we should make full use of the spillover effect of administrative space of land development intensity to achieve the sustainable development.
In recent years, the spatial non-integration effect of administrative regions and economic zones existed in China, and as an important means of spatial governance, territorial spatial planning is the important foundation for the high-quality development of cross-regional. The research area is Beijing-Tianjin-Hebei agglomeration, explores the spatio-temporal change and driving mechanism of land development intensity, and embeded the adjacency relationship between county-level administrative units into the spatial econometric model to explore the influence mechanism of land development intensity under the different scenarios of administrative spatial spillover effect. The results show that the land development intensity of different county-level administrative unites were quite different in the Beijing-Tianjin-Hebei agglomeration, and the spatio-temporal differentiation and spatial agglomeration was significantly. The land development intensity of most county-level administrative units in the Beijing-Tianjin-Hebei agglomeration were improved, but the spatial pattern of "high in the southeast and low in the northwest" has not change. Population density, the proportion of tertiary industry added value and per capita GDP had significant effects on the land development intensity. The spatial distribution of land development intensity has significant positive spatial correlation, and the direct spatial spillover effect is obvious. From 2010 to 2019, the administrative spatial spillover effect of different adjacent relationships were different, and the spillover of adjacent relationships of different types of county-level administrative units was enhanced. In the future , we should make full use of the spillover effect of administrative space of land development intensity to achieve the sustainable development.
Abstract:
Abstract In order to investigate whether the mycelia of Poria cocos can ferment and utilize Lentinula edodes stalk substrate and improve its nutritional value and biological activity. P. cocos was cultured on the solid medium using L. edodes stalk as the sole substrate. The kinetic changes of enzyme activities, nutrient composition and antioxidant activity were measured. The results showed that the cellulose exonuclease activity reached 46.14 U/g on the 6th day of the fermentation process, subsequently decreased rapidly to 17.15 U/g, and remained essentially unchanged on the 18th day. The activity of carboxymethyl cellulase and xylanase reached 77.70 U/g and 74.23 U/g, respectively, on the 12th days of fermentation and then gradually decreased. The β-glucosidase activity reached 75.06 U/g on the 18th of the fermentation and then gradually decreased. In comparison with the unfermented L. edodes stalk substrate, total sugar, soluble protein and insoluble dietary fiber of fermented L. edodes stalk substrate showed significant decrease, whereas the contents of reducing sugar, polysaccharidecontents, total phenols, total flavone, amino nitrogen and soluble dietary fiber were increased obviously. The antioxidant capacity of water extracts of fermentation substrate was significantly improved as well. The DPPH radical scavenging rate and the hydroxyl radical scavenging rate increased by 97.75% and 38.15% respectively. The results showed that P. cocos could fermet L. edodes stalk, alter the nutritional components of L. edodes stalk, and that the fermentation substrate exhibited enhanced free radical scavenging ability.
Abstract In order to investigate whether the mycelia of Poria cocos can ferment and utilize Lentinula edodes stalk substrate and improve its nutritional value and biological activity. P. cocos was cultured on the solid medium using L. edodes stalk as the sole substrate. The kinetic changes of enzyme activities, nutrient composition and antioxidant activity were measured. The results showed that the cellulose exonuclease activity reached 46.14 U/g on the 6th day of the fermentation process, subsequently decreased rapidly to 17.15 U/g, and remained essentially unchanged on the 18th day. The activity of carboxymethyl cellulase and xylanase reached 77.70 U/g and 74.23 U/g, respectively, on the 12th days of fermentation and then gradually decreased. The β-glucosidase activity reached 75.06 U/g on the 18th of the fermentation and then gradually decreased. In comparison with the unfermented L. edodes stalk substrate, total sugar, soluble protein and insoluble dietary fiber of fermented L. edodes stalk substrate showed significant decrease, whereas the contents of reducing sugar, polysaccharidecontents, total phenols, total flavone, amino nitrogen and soluble dietary fiber were increased obviously. The antioxidant capacity of water extracts of fermentation substrate was significantly improved as well. The DPPH radical scavenging rate and the hydroxyl radical scavenging rate increased by 97.75% and 38.15% respectively. The results showed that P. cocos could fermet L. edodes stalk, alter the nutritional components of L. edodes stalk, and that the fermentation substrate exhibited enhanced free radical scavenging ability.
Abstract:
In order to investigate the role of bacterial microbial communities in the pathogenesis of poplar wet heartwood, the wet heartwood and normal wood of 6-year-old Populus deltoides Bartr. ‘Huashi2’ were studied, and high-throughput sequencing of the V5-V7 region of the 16S rRNA gene was used to sequence and analyze the bacteria informatically. Principal component analysis, α-diversity index analysis and microbial network analysis techniques were used to explore the differences in the structure and composition of the bacterial microbial communities in the wet heartwood and normal timber of 6-year-old poplar. The results showed that:At the genus level of the bacterial microbial community of 6-year-old Populus deltoides Bartr. ‘Huashi2’ wet heartwood and normal timber, the highest bacterial abundance was found in the genera of Ralstonia and Bacteroides, and the genera of Bacteroides , Pleomorphomonas and Hydrogenispora accounted for a significantly higher proportion of the wet heartwood than that of the normal timber ( p<0.05). Functional analysis of microbial communities showed that Ralstonia were mostly phytopathogenic bacteria, which widely existed in wet heartwood. Analysis of the alpha diversity index showed that wet heartwood community diversity and species distribution evenness were higher than that of normal wood, and the total number of species was lower than that of normal wood.. Co-occurrence network study showed that there were more competition and antagonism among bacterial microorganisms in poplar normal timber, and the community was more unstable, while the bacterial microbial community in wet heartwood was more stable. The analysis of key microorganisms showed that the key bacterial microorganisms in the wet heartwood of 6-year-old poplar were Aquabacterium, WCHB1-32, etc., and the key bacterial microorganisms in the normal heartwood of 6-year-old poplar were Pleomorphomonas, Dysgonomonas, etc. These key microorganisms play an important role in stabilizing the microbial network structure of wet heartwood. In this study, we found that poplar wet heartwood formation is influenced by multiple factors and results from the joint action of microbial communities.
In order to investigate the role of bacterial microbial communities in the pathogenesis of poplar wet heartwood, the wet heartwood and normal wood of 6-year-old Populus deltoides Bartr. ‘Huashi2’ were studied, and high-throughput sequencing of the V5-V7 region of the 16S rRNA gene was used to sequence and analyze the bacteria informatically. Principal component analysis, α-diversity index analysis and microbial network analysis techniques were used to explore the differences in the structure and composition of the bacterial microbial communities in the wet heartwood and normal timber of 6-year-old poplar. The results showed that:At the genus level of the bacterial microbial community of 6-year-old Populus deltoides Bartr. ‘Huashi2’ wet heartwood and normal timber, the highest bacterial abundance was found in the genera of Ralstonia and Bacteroides, and the genera of Bacteroides , Pleomorphomonas and Hydrogenispora accounted for a significantly higher proportion of the wet heartwood than that of the normal timber ( p<0.05). Functional analysis of microbial communities showed that Ralstonia were mostly phytopathogenic bacteria, which widely existed in wet heartwood. Analysis of the alpha diversity index showed that wet heartwood community diversity and species distribution evenness were higher than that of normal wood, and the total number of species was lower than that of normal wood.. Co-occurrence network study showed that there were more competition and antagonism among bacterial microorganisms in poplar normal timber, and the community was more unstable, while the bacterial microbial community in wet heartwood was more stable. The analysis of key microorganisms showed that the key bacterial microorganisms in the wet heartwood of 6-year-old poplar were Aquabacterium, WCHB1-32, etc., and the key bacterial microorganisms in the normal heartwood of 6-year-old poplar were Pleomorphomonas, Dysgonomonas, etc. These key microorganisms play an important role in stabilizing the microbial network structure of wet heartwood. In this study, we found that poplar wet heartwood formation is influenced by multiple factors and results from the joint action of microbial communities.
Yanzhao Chen, Shulin Xu, Chenchen Qu, Ming Zhang, Chunhui Gao, Yichao Wu, Ke Dai, Qiaoyun Huang, Peng Cai
Abstract:
Interfacial interactions form the foundation for bacterial adhesion, colonization, biofilm formation, and control the ecological function of bacteria in the environment. Meanwhile, the processes also play a crucial role in nutrient absorption and against pathogenic microorganisms by plants. Research on microbe-plant rhizosphere interactions has predominantly studied from the ecological and molecular biological perspectives, employing various omics techniques to study the effects of root exudates on the quantity, community composition, and physiological functions of rhizosphere microorganisms. However, the physical and chemical interfacial mechanisms involved in bacterial colonization have been overlooked. This review explores the mechanisms of interfacial interactions, discussing the regulatory effects of different types of root exudates on bacterial surface properties, extracellular polymeric substances (EPS) molecular composition, and their adhesion functions. Furthermore, the research methods related to the dynamics, structure, and energy of rhizosphere bacterial adhesion and the research frontiers, such as rhizosphere biomolecular characterization, adhesion functionality of these biomolecules, and in situ observation methods were summarized. Interfacial regulation is a key approach for the targeted selection of rhizosphere microorganisms. Advancing our knowledge of the molecular mechanisms of microbial rhizosphere adhesion can help us better use of beneficial microbes in agriculture and develop more effective bio-organic fertilizers.
Interfacial interactions form the foundation for bacterial adhesion, colonization, biofilm formation, and control the ecological function of bacteria in the environment. Meanwhile, the processes also play a crucial role in nutrient absorption and against pathogenic microorganisms by plants. Research on microbe-plant rhizosphere interactions has predominantly studied from the ecological and molecular biological perspectives, employing various omics techniques to study the effects of root exudates on the quantity, community composition, and physiological functions of rhizosphere microorganisms. However, the physical and chemical interfacial mechanisms involved in bacterial colonization have been overlooked. This review explores the mechanisms of interfacial interactions, discussing the regulatory effects of different types of root exudates on bacterial surface properties, extracellular polymeric substances (EPS) molecular composition, and their adhesion functions. Furthermore, the research methods related to the dynamics, structure, and energy of rhizosphere bacterial adhesion and the research frontiers, such as rhizosphere biomolecular characterization, adhesion functionality of these biomolecules, and in situ observation methods were summarized. Interfacial regulation is a key approach for the targeted selection of rhizosphere microorganisms. Advancing our knowledge of the molecular mechanisms of microbial rhizosphere adhesion can help us better use of beneficial microbes in agriculture and develop more effective bio-organic fertilizers.
Abstract:
In order to realize on-site sampling of trace pollutants in environmental water, a large-capacity solid-phase microextraction (SPME) tube was developed, and an on-site SPME sampling device was constructed. The performance of the SPME tube and the on-site SPME device was evaluated using gas chromatography-flame ionization detector for the analysis of phthalates and polycyclic aromatic hydrocarbons (PAHs). Results show that the extraction performance of the tube is stable and reproducible, and the sampling device is flexible to be assembled and easy to carry. The detection limits obtained by the on-site SPME device with 3 SPME tubes were 0.01~0.04 ng/L, which were 6~14 times higher than that of a single SPME tube, and 36~53 times higher than that of the SPME fiber. The recoveries were 92.0%~115.7% and the relative standard deviations were 1.5%~13.1% at different spiking levels. The device has a strong enrichment capacity, and can be flexibly constructed and automated, which can be used for efficient monitoring of different pollutants in environmental water.
In order to realize on-site sampling of trace pollutants in environmental water, a large-capacity solid-phase microextraction (SPME) tube was developed, and an on-site SPME sampling device was constructed. The performance of the SPME tube and the on-site SPME device was evaluated using gas chromatography-flame ionization detector for the analysis of phthalates and polycyclic aromatic hydrocarbons (PAHs). Results show that the extraction performance of the tube is stable and reproducible, and the sampling device is flexible to be assembled and easy to carry. The detection limits obtained by the on-site SPME device with 3 SPME tubes were 0.01~0.04 ng/L, which were 6~14 times higher than that of a single SPME tube, and 36~53 times higher than that of the SPME fiber. The recoveries were 92.0%~115.7% and the relative standard deviations were 1.5%~13.1% at different spiking levels. The device has a strong enrichment capacity, and can be flexibly constructed and automated, which can be used for efficient monitoring of different pollutants in environmental water.
Abstract:
Gamma-aminobutyric acid (GABA) is a four carbon, non-protein amino acid with widely application prospects in food, agriculture, medicine, chemical and other fields. The production of GABA through microbial synthesis has been gaining increasing attention due to its mildness and sustainable development advantages. Therefore, in order to achieve an environmentally, convenient, and more efficient metabolic production pathway for GABA that meets the stringent requirements for additives in the food, pharmaceutical, and livestock industries, the main synthesis pathways of GABA and the research progress of microbial synthesis of GABA are introduced systematically, and the future research directions and development trends are prospected.
Gamma-aminobutyric acid (GABA) is a four carbon, non-protein amino acid with widely application prospects in food, agriculture, medicine, chemical and other fields. The production of GABA through microbial synthesis has been gaining increasing attention due to its mildness and sustainable development advantages. Therefore, in order to achieve an environmentally, convenient, and more efficient metabolic production pathway for GABA that meets the stringent requirements for additives in the food, pharmaceutical, and livestock industries, the main synthesis pathways of GABA and the research progress of microbial synthesis of GABA are introduced systematically, and the future research directions and development trends are prospected.
GUO Xiaolong, DENG Can, ZHANG Mingchun, GAO Ruijie, LIU Pulin, ZHANG Enhua, LIANG Xiaotong, YU Li, XIONG Lijun, MIAO Lihong
Abstract:
Using wheat as raw material, Bacillus licheniformis BL44, Saccharomyces cerevisiae SCY62, Paecilomyces variotii PV3, Rhizomucor pusillus RP1 and Thermoascus crustaceus TC1, which were isolated and screened from the high-temperature Daqu, were prepared into a solid agent and two synthetic microbial communities were constructed according to different addition ratios. The synthetic microbial community was used to replace the traditional Muqu (CK) to make high-temperature Daqu and carry out comparative laboratory brewing experiments. High-throughput sequencing results revealed that the dominant fungal genus of the three kinds of Daqu was Lichtheimia, and the dominant bacterial genus was Bacillus. The results of physicochemical indexes of the Daqu showed that the liquefaction and saccharification abilities of the high-temperature Daqu inoculated with the synthetic microbial communities were significantly improved compared to CK. The results of gas chromatography-mass spectrometry analysis showed that there were 69 types of volatile compounds produced by artificially synthesized microbial communities in Daqu, which was higher than the 68 types inoculated with traditional Muqu. In addition, inoculating artificial synthetic microbial communities instead of traditional Muqu can significantly increase the content of tetramethylpyrazine in Daqu and fermented grains. The content of tetramethylpyrazine in Daqu inoculated with artificial synthetic microbial group 1 and microbial group 2 were 31903.5 μg/kg and 56733.6 μg/kg respectively, increased by 2.80 and 4.99 times respectively compared to CK. In the high-temperature stacked fermentation mash, the content of tetramethylpyrazine inoculated with artificial synthetic bacterial group 1 and bacterial group 2 were 755.8 μg/kg and 2741.4 μg/kg respectively, increased by 4.03 and 14.61 times respectively compared to CK. This study provides a certain theoretical basis for the application of synthetic microbial community in Daqu.
Using wheat as raw material, Bacillus licheniformis BL44, Saccharomyces cerevisiae SCY62, Paecilomyces variotii PV3, Rhizomucor pusillus RP1 and Thermoascus crustaceus TC1, which were isolated and screened from the high-temperature Daqu, were prepared into a solid agent and two synthetic microbial communities were constructed according to different addition ratios. The synthetic microbial community was used to replace the traditional Muqu (CK) to make high-temperature Daqu and carry out comparative laboratory brewing experiments. High-throughput sequencing results revealed that the dominant fungal genus of the three kinds of Daqu was Lichtheimia, and the dominant bacterial genus was Bacillus. The results of physicochemical indexes of the Daqu showed that the liquefaction and saccharification abilities of the high-temperature Daqu inoculated with the synthetic microbial communities were significantly improved compared to CK. The results of gas chromatography-mass spectrometry analysis showed that there were 69 types of volatile compounds produced by artificially synthesized microbial communities in Daqu, which was higher than the 68 types inoculated with traditional Muqu. In addition, inoculating artificial synthetic microbial communities instead of traditional Muqu can significantly increase the content of tetramethylpyrazine in Daqu and fermented grains. The content of tetramethylpyrazine in Daqu inoculated with artificial synthetic microbial group 1 and microbial group 2 were 31903.5 μg/kg and 56733.6 μg/kg respectively, increased by 2.80 and 4.99 times respectively compared to CK. In the high-temperature stacked fermentation mash, the content of tetramethylpyrazine inoculated with artificial synthetic bacterial group 1 and bacterial group 2 were 755.8 μg/kg and 2741.4 μg/kg respectively, increased by 4.03 and 14.61 times respectively compared to CK. This study provides a certain theoretical basis for the application of synthetic microbial community in Daqu.
Abstract:
Algae and bacteria play important roles in the biogeochemical cycle, energy flows of important elements in the ecosystem. Some bacteria can have beneficial interactions with algae by promoting the growth of algae and helping algae resist stress, thereby having important impacts on the survival, competition, and physiological functions of both partners. This article reviewed the main ways of interaction, microbial communities, molecular mechanisms, and the recent applications of beneficial interactions between algae and bacteria in the treatment of environmental pollution, biomass energy, and synthetic biology to in-depth study the beneficial interactions between algae and bacteria. The studies on the beneficial interactions between algae and bacteria were prospected. It will not only play an important role in understanding the structure and function of microbial community in aquatic environments, and the mechanisms and effects of relationships among microbial species, but also provide important scientific basis for maintaining the health of ecosystems, mining and utilizing the biological resources for the benefit of humanity.
Algae and bacteria play important roles in the biogeochemical cycle, energy flows of important elements in the ecosystem. Some bacteria can have beneficial interactions with algae by promoting the growth of algae and helping algae resist stress, thereby having important impacts on the survival, competition, and physiological functions of both partners. This article reviewed the main ways of interaction, microbial communities, molecular mechanisms, and the recent applications of beneficial interactions between algae and bacteria in the treatment of environmental pollution, biomass energy, and synthetic biology to in-depth study the beneficial interactions between algae and bacteria. The studies on the beneficial interactions between algae and bacteria were prospected. It will not only play an important role in understanding the structure and function of microbial community in aquatic environments, and the mechanisms and effects of relationships among microbial species, but also provide important scientific basis for maintaining the health of ecosystems, mining and utilizing the biological resources for the benefit of humanity.
Abstract:
The specialist predator bacteria bdellovibrio-and-like organisms (BALOs) are highly valued for their potential applications in agriculture, industry and medicine, especially in the treatment of antibiotic-resistant pathogenic bacterial infections. However, many basic scientific questions about BALOs have been unclear in the past decades, which is the fundamental reason why this type of bacteria has not been effectively developed and utilized for the time being. Recently, many progresses have been made concerning their life cycle, predation mechanisms, resource distribution and diversity, and their applications in medicine, agriculture, or industry. Especially since the formal establishment of the phylum Bdellovibrionota in 2021, there has been an explosive growth in related research. This review will systematically review the previous advances of BALOs and highlight the recently reported outstanding achievements, such as the study of predation mechanism, to promote the understanding and further applications of the resources of BALOs and to guide the future research on BALOs.
The specialist predator bacteria bdellovibrio-and-like organisms (BALOs) are highly valued for their potential applications in agriculture, industry and medicine, especially in the treatment of antibiotic-resistant pathogenic bacterial infections. However, many basic scientific questions about BALOs have been unclear in the past decades, which is the fundamental reason why this type of bacteria has not been effectively developed and utilized for the time being. Recently, many progresses have been made concerning their life cycle, predation mechanisms, resource distribution and diversity, and their applications in medicine, agriculture, or industry. Especially since the formal establishment of the phylum Bdellovibrionota in 2021, there has been an explosive growth in related research. This review will systematically review the previous advances of BALOs and highlight the recently reported outstanding achievements, such as the study of predation mechanism, to promote the understanding and further applications of the resources of BALOs and to guide the future research on BALOs.
Abstract:
Sinking and floating motion control is an important means to improve the quality of mariculture cages and ensure the safety of aquaculture. However, it is difficult to achieve accurate sinking and floating control due to multiple factors such as complex sea conditions and uneven loads. Aiming at the problem of sinking and floating control of a mariculture cage, this paper carries out modeling and collaborative control strategy research. Firstly, based on the analysis of the characteristics of cage structure, actuator and other objects, the dynamic model of sinking and floating is established. Secondly, based on the principle of parallel drive, a double closed-loop master-slave cooperative cage sinking and floating motion control strategy is proposed : the outer loop realizes the cooperative water inflow planning of multi-ballast tanks based on PID master-slave synchronization strategy ; the inner loop designs an efficient water inlet controller based on fuzzy sliding mode control and Lyapunov theory. Finally, through multi-condition digital simulation, the ballast tank water control algorithm and the cage sinking and floating cooperative motion control scheme are verified. The research results show that the control algorithm proposed in this paper can realize efficient water inflow control of ballast tanks, and can achieve high-precision sinking-floating coordinated control under different wave disturbances, which can provide technical support for practical applications.
Sinking and floating motion control is an important means to improve the quality of mariculture cages and ensure the safety of aquaculture. However, it is difficult to achieve accurate sinking and floating control due to multiple factors such as complex sea conditions and uneven loads. Aiming at the problem of sinking and floating control of a mariculture cage, this paper carries out modeling and collaborative control strategy research. Firstly, based on the analysis of the characteristics of cage structure, actuator and other objects, the dynamic model of sinking and floating is established. Secondly, based on the principle of parallel drive, a double closed-loop master-slave cooperative cage sinking and floating motion control strategy is proposed : the outer loop realizes the cooperative water inflow planning of multi-ballast tanks based on PID master-slave synchronization strategy ; the inner loop designs an efficient water inlet controller based on fuzzy sliding mode control and Lyapunov theory. Finally, through multi-condition digital simulation, the ballast tank water control algorithm and the cage sinking and floating cooperative motion control scheme are verified. The research results show that the control algorithm proposed in this paper can realize efficient water inflow control of ballast tanks, and can achieve high-precision sinking-floating coordinated control under different wave disturbances, which can provide technical support for practical applications.
Abstract:
In order to explore the mechanism and effect of urban greenbelts on reducing air particulate matter, the green space of Luojiagang Greenbelt Park in Wuhan and its surrounding built environment were selected as the research object. Three days with clear and windless weather and similar meteorological conditions in winter were selected for repeated observation. The method of combining LUR model and principal component analysis was used to analyze the mitigation effect of urban greenbelt on air PM10 and PM2.5 concentrations in winter, and to identify the key influencing factors, aiming to provide scientific basis for the planning and construction of urban greenbelt built environment. The results show that based on the LUR model, the mitigation effect of urban greenbelt on air PM10 and PM2.5 will be disturbed by the surrounding traffic pollution emissions, and the microclimate conditions created by urban greenbelt with different widths will also have a certain impact on the concentration of air PM10 and PM2.5. The research shows that the greenbelt has a width effect on the mitigation of air PM10 and PM2.5, and the green space with a width of 30?40m has the most significant reduction efficiency of air PM10 in winter. At the same time, the study found that the concentration of air PM10 and PM2.5 in the urban green belt in winter will be higher than that of the adjacent road position, and there is a significant accumulation effect of air PM10 and PM2.5 in the urban greenbelt. It will provide important scientific guidance for the high-quality development of the PM retention effect of the urban greenbelt along the road.
In order to explore the mechanism and effect of urban greenbelts on reducing air particulate matter, the green space of Luojiagang Greenbelt Park in Wuhan and its surrounding built environment were selected as the research object. Three days with clear and windless weather and similar meteorological conditions in winter were selected for repeated observation. The method of combining LUR model and principal component analysis was used to analyze the mitigation effect of urban greenbelt on air PM10 and PM2.5 concentrations in winter, and to identify the key influencing factors, aiming to provide scientific basis for the planning and construction of urban greenbelt built environment. The results show that based on the LUR model, the mitigation effect of urban greenbelt on air PM10 and PM2.5 will be disturbed by the surrounding traffic pollution emissions, and the microclimate conditions created by urban greenbelt with different widths will also have a certain impact on the concentration of air PM10 and PM2.5. The research shows that the greenbelt has a width effect on the mitigation of air PM10 and PM2.5, and the green space with a width of 30?40m has the most significant reduction efficiency of air PM10 in winter. At the same time, the study found that the concentration of air PM10 and PM2.5 in the urban green belt in winter will be higher than that of the adjacent road position, and there is a significant accumulation effect of air PM10 and PM2.5 in the urban greenbelt. It will provide important scientific guidance for the high-quality development of the PM retention effect of the urban greenbelt along the road.
Abstract:
The transformation of complex substrates in nature is driven by the division of labor among different species within microbial communities. Lignocellulose, the most abundant macromolecular biomass on Earth, holds significant societal, economic, and environmental benefits for its biotransformation. Consolidated bioprocessing (CBP), integrating the traditional steps of enzyme production, hydrolysis, and fermentation into a single-step process, is considered the ideal form of lignocellulose conversion. Although metabolic engineering can enable CBP based on a single strain, the excessively high metabolic stress leads to unsatisfactory conversion efficiency. Allocating different steps to various strains, with the community achieving CBP, has become a focal point in lignocellulose conversion. However, due to a lack of systematic understanding and rational design of interspecies division of labor, the efficiency and stability of artificial microbial communities still need to be improved. This article focuses on the interspecies division of labor within natural lignocellulose-degrading communities, reviewing the current collaborative patterns between species from the perspectives of substrate synergistic hydrolysis, cross-feeding of nutritional factors, and "sugar cheaters" control. It also briefly introduces the application of interspecific division of labor in lignocellulose conversion, as well as the challenges and future development directions in studying the interspecies division of labor within natural lignocellulose communities, providing design principles for constructing CBP communities and promoting the efficient conversion of lignocellulose.
The transformation of complex substrates in nature is driven by the division of labor among different species within microbial communities. Lignocellulose, the most abundant macromolecular biomass on Earth, holds significant societal, economic, and environmental benefits for its biotransformation. Consolidated bioprocessing (CBP), integrating the traditional steps of enzyme production, hydrolysis, and fermentation into a single-step process, is considered the ideal form of lignocellulose conversion. Although metabolic engineering can enable CBP based on a single strain, the excessively high metabolic stress leads to unsatisfactory conversion efficiency. Allocating different steps to various strains, with the community achieving CBP, has become a focal point in lignocellulose conversion. However, due to a lack of systematic understanding and rational design of interspecies division of labor, the efficiency and stability of artificial microbial communities still need to be improved. This article focuses on the interspecies division of labor within natural lignocellulose-degrading communities, reviewing the current collaborative patterns between species from the perspectives of substrate synergistic hydrolysis, cross-feeding of nutritional factors, and "sugar cheaters" control. It also briefly introduces the application of interspecific division of labor in lignocellulose conversion, as well as the challenges and future development directions in studying the interspecies division of labor within natural lignocellulose communities, providing design principles for constructing CBP communities and promoting the efficient conversion of lignocellulose.
Abstract:
To investigate the effect of frying pretreatment on the quality of fish head pots, using conditioned silver carp fish head as raw material, the color, protein solubility, malondialdehyde content, basic nutritional components and other indicators of the fried fish head and fish head pot were measured, and suitable pre frying conditions were selected through sensory analysis. Results showed that the color and protein solubility of fish head first increased and then decreased with the increase of frying temperature, while the malondialdehyde content was the opposite. The nutrient content of fish head pot increases with the increase of frying temperature. The dissolution of protein, fat and other nutrients in fish head pot fried at medium and high temperature (180 ℃, 200 ℃) was higher than that in low temperature frying group (160 ℃), while the color and taste sensory quality of fish head pot fried at high temperature (200 ℃) was lower than that in medium temperature frying group (180 ℃). With the extension of frying time, the contents of protein, fat and solid in fish head pot increased gradually, and the total free amino group content first increased and then decreased, while the taste profile and sensory quality first increased and then there was no significant difference. When frying for 120s, the fish head pot had more protein dissolved and lower fat content, and its color, taste and sensory quality were also the best. In conclusion, pre-frying at 180°C for 120s was the optimum condition for fish head pot.
To investigate the effect of frying pretreatment on the quality of fish head pots, using conditioned silver carp fish head as raw material, the color, protein solubility, malondialdehyde content, basic nutritional components and other indicators of the fried fish head and fish head pot were measured, and suitable pre frying conditions were selected through sensory analysis. Results showed that the color and protein solubility of fish head first increased and then decreased with the increase of frying temperature, while the malondialdehyde content was the opposite. The nutrient content of fish head pot increases with the increase of frying temperature. The dissolution of protein, fat and other nutrients in fish head pot fried at medium and high temperature (180 ℃, 200 ℃) was higher than that in low temperature frying group (160 ℃), while the color and taste sensory quality of fish head pot fried at high temperature (200 ℃) was lower than that in medium temperature frying group (180 ℃). With the extension of frying time, the contents of protein, fat and solid in fish head pot increased gradually, and the total free amino group content first increased and then decreased, while the taste profile and sensory quality first increased and then there was no significant difference. When frying for 120s, the fish head pot had more protein dissolved and lower fat content, and its color, taste and sensory quality were also the best. In conclusion, pre-frying at 180°C for 120s was the optimum condition for fish head pot.
Abstract:
Biological soil crusts are the main cover layer of the soil surface in arid areas, in which the microorganisms play an important role in regulating the climate sensitivity of the carbon cycle in dry areas. At present, there are some controversies over the effects of climate warming on the microbial communities and their respiration of biocrusts. In order to accurately predict the carbon balance in arid areas in the future scenarios, this study summarized the carbon emission patterns of different experimental periods, different seasons, and different types of biocrusts through the warming experiments simulating climate warming, and explored the internal reasons for the differences in carbon emissions based on the analyses of the changes in microbial abundance and organic carbon. Short-term warming (＜ 2 a) led to a significant decrease in mosses or lichens abundance of biocrusts, which increased soil organic carbon content, with a concomitant increase in net carbon emissions depends on soil water content. Long-term warming (＞ 5 a) reduced microbial sensitivity to temperature and humidity, and microbial abundance and composition stabilized, resulting in relatively stable of organic carbon content and net carbon emissions. These results reflect the pattern and causes of carbon emission in biocrusts, but the internal regulatory mechanisms involved by microorganisms are still unclear. Therefore, it is necessary to focus on exploring the response mechanism of crusts microbial carbon metabolism to warming in the future, which provides an important theoretical basis for assessing carbon balance in arid areas.
Biological soil crusts are the main cover layer of the soil surface in arid areas, in which the microorganisms play an important role in regulating the climate sensitivity of the carbon cycle in dry areas. At present, there are some controversies over the effects of climate warming on the microbial communities and their respiration of biocrusts. In order to accurately predict the carbon balance in arid areas in the future scenarios, this study summarized the carbon emission patterns of different experimental periods, different seasons, and different types of biocrusts through the warming experiments simulating climate warming, and explored the internal reasons for the differences in carbon emissions based on the analyses of the changes in microbial abundance and organic carbon. Short-term warming (＜ 2 a) led to a significant decrease in mosses or lichens abundance of biocrusts, which increased soil organic carbon content, with a concomitant increase in net carbon emissions depends on soil water content. Long-term warming (＞ 5 a) reduced microbial sensitivity to temperature and humidity, and microbial abundance and composition stabilized, resulting in relatively stable of organic carbon content and net carbon emissions. These results reflect the pattern and causes of carbon emission in biocrusts, but the internal regulatory mechanisms involved by microorganisms are still unclear. Therefore, it is necessary to focus on exploring the response mechanism of crusts microbial carbon metabolism to warming in the future, which provides an important theoretical basis for assessing carbon balance in arid areas.
Abstract:
In order to explore the feasible methods for coremoval of cadmium(Cd) and arsenic(As) in soil, we selected Enterobacter sp. A11 and Comamonas sp. A23 due to their ability to oxidize Fe and Mn compounds, and studied immobilization capabilities for Cd and As of the production of biological Fe and Mn oxides （BFMO）. The SEM results showed that Fe-Mn oxides were located on the cell surface, leading to bacterial aggregation. Moreover, pot experiment showed strains A11 and A23 immobilized Cd and As in soils (reduce the proportion of bioavailable Cd and As, and increase the proportion of unavailable Cd and As), and exhibited a reduction in the accumulation of Cd and As in the aboveground and root parts of Brassica rapa L. The BFMO production of strains A11 and A23 exhibits excellent immobilization capabilities for Cd and As.
In order to explore the feasible methods for coremoval of cadmium(Cd) and arsenic(As) in soil, we selected Enterobacter sp. A11 and Comamonas sp. A23 due to their ability to oxidize Fe and Mn compounds, and studied immobilization capabilities for Cd and As of the production of biological Fe and Mn oxides （BFMO）. The SEM results showed that Fe-Mn oxides were located on the cell surface, leading to bacterial aggregation. Moreover, pot experiment showed strains A11 and A23 immobilized Cd and As in soils (reduce the proportion of bioavailable Cd and As, and increase the proportion of unavailable Cd and As), and exhibited a reduction in the accumulation of Cd and As in the aboveground and root parts of Brassica rapa L. The BFMO production of strains A11 and A23 exhibits excellent immobilization capabilities for Cd and As.
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:
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:
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:
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.
Display Method:
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.
More+
About UsMore+
- ·Aim and Scope07-23
- ·About the Editors07-23
- ·Editorials Board07-23
Introduction of
the journal
More+
Periodical information
- Supervisor:
Huazhong A gricultural University
- Unit:
Huazhong A gricultural University
- Chief Editor：
ZHANG Xianlong
- Edited and:
Editorial Department of Journal of Huazhong
- Address:
No.1 Shizishan Street,Hongshan District,Wuhan, Hubei,China
- Tel：
027-87287364
- E-mail:
hnlkxb@mail.hzau.edu.cn
- Domestic distribution:
Wuhan post office
- Domestic order:
Post offices all over the country
- Overseas Distributort:
China International Book Trading Corporation(P.O.Box 399,Beijing 100044,China)
- ISSN:
1000-2421
- CN:
42-1181/S
- Postal code:
38-120
- Unit Price:
20.00
- Frequency ：
Bimonthly
WeChat
Access statistics
- Today's visits:
- Total visits: