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    2022,41(3):1-10 , DOI: 10.13300/j.cnki.hnlkxb.2022.03.001
    Abstract:
    Land space ecological restoration is a process of continuous optimization of man-land relationship. Under the background and development goal of comprehensively promoting the rural ecology revitalization, the systematic, comprehensive, global and overall territorial space ecological restoration of rural is the realistic demand of the sustainable development of human society. This article took the ecological restoration of territorial space under the background of rural revitalization from 2004 to 2021 as the retrieval subject, and obtained 830 literatures. The map co-occurrence relationship between the ecological restoration of territorial space and rural revitalization in China was summarized based on bibliometrics. It is defined that the new stage of ecological restoration of the territorial space should focus on the coupling of the man-land system in the future. This paper proposes to explore the implementation path and technology integration mode of rural ecological restoration in the advanced stage of man-land system coupling from the perspective of Rural production-life-ecology space, from the aspects of production-ecology, life-ecology and human welfare-ecology. The systematic view of rural production-life-ecology space dynamics should be improved based on the new thinking of ecological restoration of territorial space. The development of ecological restoration should be pushed forward to an advanced stage on the basis of improving human ecological well-being. The implementation of important strategies for the ecological civilization and rural revitalization should be carried forward continuously.
    2022,41(3):11-19 , DOI: 10.13300/j.cnki.hnlkxb.2022.03.002
    Abstract:
    In order to provide reference for the follow-up theoretical study and construction practice of digital rural in China,this study adopts the method of bibliometrics and uses the CiteSpace software to draw the knowledge maps of 804 study papers from CSSCI on digital rural from 2016 to 2021. Based on the bibliometric results,the core knowledge elements,front hotspots and domain themes of digital rural are analyzed in depth. The results show that Chinese digital rural study and construction practice has four characteristics: taking historical tasks as the main line,relying on digital information technology,focusing on economic construction,and making joint efforts in multidimensional fields. The prospects of studies are put forward from the aspects of the strength,methods,contents and key tasks of digital rural studies. And the six systematic countermeasures and suggestions for the practice of constructing digital rural including broadening the revitalization path of digital rural,creating a good digital ecological environment in rural areas,improving the quality and efficiency of digital agriculture construction,strengthening new formats of digital rural economy,improving governance performance of digital rural,and adhering to the in-depth promotion of multidimensional fields are given.
    2022,41(3):20-26 , DOI: 10.13300/j.cnki.hnlkxb.2022.03.003
    Abstract:
    During the period of rapid urbanization,the shrinking spatial structure of rural population has become more and more simplistic and linear,resulting in a reduction in the social interaction that the structure can carry,and it is difficult to meet the needs of the sustainable development of social,economic and cultural space of villages in the context of rural revitalization.Based on the relevant theories and methods of spatial vitality structure,this paper identifies the vitality structure types of traditional rural space,finds that traditional villages have the semi-network characteristics of “many nodes,overlapping layers and moderate correlation”,constructs a semi-network structure model to stimulate rural vitality,and uses this model to improve the node structure,skillfully set up cross-level overlap reshape the structural vitality of the three industry integration demonstration village by realizing medium correlation.It is expected that the semi-network living structure model will promote the rural revitalization construction in the regions of plains,rivers and lakes.
    2022,41(3):27-34 , DOI: 10.13300/j.cnki.hnlkxb.2022.03.004
    Abstract:
    A preliminary system of evaluating rural landscape image was constructed based on nostalgia to construct a model of evaluating rural landscape image to understand the crux of the disappearance of a rural landscape.The fuzzy Delphi was used to screen the factors for evaluation.Taking the rural areas in southern Fujian as an example,each factor was evaluated through questionnaires,and then the multi-criteria compromise evaluation method was used to evaluate the rural landscape image in southern Fujian.The results showed that naturalness and vividness were the most important landscape elements in the rural areas in southern Fujian in terms of visual cognition.The sense of dependence and belonging was the most in need of improvement in terms of rural emotions.The empirical results showed that the evaluation model proposed can clarify the advantages and disadvantages of the current landscape.It will provide a reference for the continuation of intentions for rural landscape images.
    2022,41(3):35-46 , DOI: 10.13300/j.cnki.hnlkxb.2022.03.005
    Abstract:
    Reasonable matching of workplace and residence space is a difficult problem that urban researchers have been focusing on for a long time, and suburbs are one of the most prominent regional spaces for matching the workplace and residence. In-depth research on the characteristics of workplace and residence space in the suburbs is an important way to explore the spatial relationship of urban and rural functions. It is of great significance for resolving the contradiction of the dual structure of urban and rural areas and realizing the overall development of urban and rural areas. This article focuses on the suburbs of Hefei City, uses cell phone signaling data covering the whole city area to identify suburban working and residential populations, and develops a visual analysis of the distribution pattern and characteristics of the workplace and residence space in suburbs, and then uses the jobs-housing self-containment index, jobs-housing balance index and spatial mismatch index to analyze the reasonable degree of matching of suburban workplace and residence space under different spatial scales, and discusses the relationship between the workplace and residence space in the suburbs and the central areas of Hefei City. Results of qualitative and quantitative analyses showed that the suburbs of Hefei City were dominated by residential functions, and the spatial distribution of the workplace and residence space was generally uneven. Only a few towns in remote suburban had a high degree of integrating the space of workplace and residence. Most of the suburban townships and streets did not match the functions of workplace and residence, and the central area and the suburbs had a complementary relationship in spatial function. In the future, it is still necessary to further combine multi-source data to explore scientific factors affecting the distribution of the workplace and residence space in suburban areas and methods for optimizing spatial layout.
    2022,41(3):47-55 , DOI: 10.13300/j.cnki.hnlkxb.2022.03.006
    Abstract:
    The ecological restoration of land space is the key and difficult point in the comprehensive restoration of mountains, rivers, forests, farmland, lakes and grasslands.This study can provide a methodological reference for the systematic identification and restoration of key areas of ecological restoration areas in territorial space through the construction of the ecological security pattern in the study area and the identification of key restoration areas.Based on the diagnosis of ecosystem problems and the construction of ecological security pattern, this paper explored the method and path of identification and restoration of key areas of ecological restoration in territorial space. The Caidian District of Wuhan City was used to systematically diagnose the degree of degradation,the type of degradation and the spatial distribution of ecosystem from three aspects including quantity,quality and spatial pattern. Based on the identification of ecological sources,the ecological resistance surface is constructed with five factors of land cover type,distance from water area,vegetation coverage,slope and altitude,and potential ecological corridors are identified by constructing the least resistance model,and then the ecological security pattern is constructed.On this basis,ecological conservation area,natural restoration area,artificial restoration area and ecological corridor construction area in Caidian District were systematically identified by integrating the diagnosis of ecosystem problem with requirements of ecological security pattern. 1 901.52 hm2 forest land and water bodies were extracted as ecological sources,18 168.12 m potential ecological corridors were identified.Corresponding ecological protection and restoration measures were proposed from four aspects above.
    2022,41(3):56-68 , DOI: 10.13300/j.cnki.hnlkxb.2022.03.007
    Abstract:
    The rapid development of urbanization leads to the transformation of land use form and function,especially in mountainous areas. At the same time,the change of landscape pattern is a prominent symbol of land use transformation,and it is of great significance to explore the relationship between them for land use and ecological management in mountainous areas. Three remote sensing satellite image data of Jinzhai County in Dabie Mountains in 1999,2009 and 2019 were used to quantitatively analyze the landscape pattern evolution characteristics of Jinzhai County by using land use transfer matrix and landscape pattern index,and study the driving forces of landscape pattern evolution of Jinzhai County by using principal component analysis. The results showed that the transformation of land use in Jinzhai County from 1999 to 2019 was characterized by the transformation from production land to living land and ecological land,with the highest transformation rate and continuous growth of construction land. The area of cultivated land and unused land decreased. The forest land and water area continued to grow steadily. In terms of type,it was mainly the conversion between cultivated land,construction land,unused land and forest land. In space,the land use transformation in Jinzhai County was mainly concentrated in the central region from 1999 to 2009,and mainly concentrated in the northeast region from 2010 to 2019. During the period,the fragmentation of landscape pattern in Jinzhai County increased,landscape heterogeneity and evenness decreased,and irregular patches increased. From 2010 to 2019,various landscape types were distributed intermittently,and landscape connectivity decreased. The comprehensive action of five driving forces of Jinzhai County including economic development,industrial level,population situation,living standard and governance environment led to the transformation of land use and the change of landscape pattern. Among them,socio-economic development was the main driving factor of landscape pattern change in Jinzhai County,while population and urban construction were the secondary driving factors. In the future,further optimized method of measuring landscape pattern evolution and in-depth studies on driving factors should be considered. The scientific and comprehensive uses of land and optimization strategies for landscape pattern are proposed.
    2022,41(3):69-78 , DOI: 10.13300/j.cnki.hnlkxb.2022.03.008
    Abstract:
    This article analyzed the effects of Internet usage on the willingness to adopt intelligent agricultural technology among large-scale pig farmers by using the survey data of large-scale pig farmers in Hubei Province and the propensity score matching method in order to promote the popularization of intelligent agricultural technology. On this basis, the Probit model was used to analyze the heterogeneity and influence paths. The results showed that the use of the Internet significantly increased the willingness to adopt intelligent production technologies including intelligent management, intelligent service and safety traceability among large-scale pig farmers. The effect was in the decreasing order of intelligent production technology, intelligent management technology, safety traceability technology and intelligent service technology. The impact of Internet usage on the willingness to adopt intelligent agricultural technology among large-scale pig farmers was heterogeneous. In terms of age, the new generation of large-scale pig farmers tended to use intelligent production technologies, and the older generation of large-scale pig farmers tended to use the other three technologies. In terms of educational background, Internet use had a greater impact on the willingness of low-educated pig farmers to adopt the four technologies compared with high-educated pig farmers. In terms of business scale, small-scale pig farmers tended to use safety traceability technologies, while large-scale pig farmers tended to use the remaining three technologies. The use of the Internet can indirectly and positively affect the adoption willingness of large-scale pig farmers by improving their technical cognition and value perception of intelligent agricultural technology.
    2022,41(3):79-86 , DOI: 10.13300/j.cnki.hnlkxb.2022.03.009
    Abstract:
    The National Key Research and Development Program is the product of the central financial science and technology plan reform during the 13th Five-Year Period.It has gradually become an important channel for China to support major public welfare research,major scientific problems,major generic key technologies and product research and development.In this paper,we take agricultural projects of 11 key projects from 2016 to 2020 as the research object,analyze the distribution of projects in major provinces and three types of units.We select livestock and poultry key project,review from project application and review,project establishment in different fields,research strength composition and trend analysis.Finally,three suggestions are put forward: the first,we should focus on national strategic needs and industrial development trends to foster new projects; the second,we should strengthen cooperation between enterprises,universities and research institutes,build an innovation consortium; the third,we should implement professional management and improve project performance.The above suggestions are intended to provide reference for research institutions and researchers to improve their ability to undertake major national research tasks.
    2022,41(3):87-95 , DOI: 10.13300/j.cnki.hnlkxb.2022.03.010
    Abstract:
    Technological optimization is the driving force and support to promote the transformation and upgrading of animal husbandry and realize the development of animal husbandry in China with high-quality.This article uses qualitative analyses to sort out the key bottlenecks of technologies faced by the development of animal husbandry in China with high-quality.With the help of R & D investment and achievements of scientific and technological award in animal husbandry in China from 2006 to 2019,the corresponding status and characteristics of research and development are further presented.The results showed that the total amount of scientific and technological achievements in animal husbandry was stable.The number of main types of achievements varied significantly and fluctuated periodically.Institutions including universities and academies of agricultural sciences are the main R & D subjects of scientific and technological achievements in animal husbandry.The R & D investment did not match its value of output.Based on the bottlenecks of science and technologies for developing the animal husbandry with high-quality,four aspects including increasing R & D investment,improving the innovation level of green technologies,promoting the linked development of mechanization and information technology,constructing a collaborative innovation system of technologies in animal husbandry are proposed to help promote the optimization of science and technologies in animal husbandry and achieve the development of animal husbandry with high-quality.
    2022,41(3):96-106 , DOI: 10.13300/j.cnki.hnlkxb.2022.03.011
    Abstract:
    In order to achieve the policy objectives of “improving product quality,increasing fishermen’s income,greening industry and optimizing water area ecology”,qualitative and case analysis methods were applied in this paper to analyze the economic and ecological benefits of China's aquaculture development.Based on the development history,culture area and culture structure of freshwater aquaculture in China,the quality and safety issues were discussed.Taking large surface aquaculture,pond culture,integrated rice-fish farming and integrated rice-crayfish farming models as examples,the ecological and economic benefits were analyzed.The results showed that since the reform and opening up in China,the area has been expanding,the production has increased rapidly,the structure of aquaculture has been continuously optimized,and the income of aquaculture has been rising,however,the environmental and product quality problems hinder the green development of freshwater aquaculture in China.Taking typical freshwater aquaculture model as an example,this paper analyzed the ecological and economic benefits of the future green and healthy aquaculture model,and in order to promote the “quality and efficiency improvement” of the three typical modes,the path of future green development was given.The large surface water needs to realize functional zoning,establish norms and standards and speed up industrial integration.It is necessary to strengthen the standardization of bulk freshwater aquaculture,apply modern mechanized equipment and popularize the pattern of compound ecological-type and circulating pond.The model of rice-fish farming needs to strengthen the characteristic brand,improve the basic breeding facilities and construct a science and technology promotion system.
    2022,41(3):107-114 , DOI: 10.13300/j.cnki.hnlkxb.2022.03.012
    Abstract:
    The CiteSpace software was used to visually analyze the information of the literature related to the green development of the breeding industry based on the literatures in the field of the green development of breeding industry included in the CNKI database from 1998 to 2021.The hotspots and frontiers in the green development of breeding industry were summarized.Results showed that the research field in green development of breeding industry is gradually active.Most of the research centers on colleges and universities form a system of scientific research, but there is a lack of close cooperation between institutional teams.The research hotspots in the green development of the breeding industry focus on three major directions including the quality and safety of the products, the ecological environment, and the strategies and models of development.The main concerns in the research on the green development of breeding industry are as follows:green development, the combination of planting and breeding, swine breeding, breeding households, and aquaculture.Results of frontier analyses showed that “swine breeding”“the combination of planting and breeding” and “economic benefit” were the trends of research in the future.How to change the development mode of the breeding industry, especially the swine breeding, how to coordinate the economic and ecological benefits, and realize the resource utilization of livestock and poultry manure by combining planting with breeding, etc.are valuable topics in the future, which still need to be explored.
    2022,41(3):115-123 , DOI: 10.13300/j.cnki.hnlkxb.2022.03.013
    Abstract:
    Methane produced by animal husbandry is the main source of agricultural greenhouse gas emissions, and reducing methane emissions has become the focus of studies in various countries. This article aimed to provide data support and scientific basis for promoting the process of methane emission reduction in animal husbandry and realizing the green and sustainable development of animal husbandry. The long-term statistical data of the FAOSTAT from 1961 to 2019 were used to analyze the changing trend of methane emission from global animal husbandry. The results showed that there were significant differences in estimated methane emissions from animal husbandry in various regions of the world from 1961 to 2019, and the overall trend was increasing. Methane emissions from ruminants increased from 68.047 9 million tons in 1961 to 103.529 1 million tons in 2019, accounting for 96.98% and 97.51% of the total methane emissions from animal husbandry. Among different species of ruminants, the top three methane emissions were beef cattle, dairy cattle, and buffalo. Its emissions increased from 34.988 7 million ton, 18.615 6 million ton, and 5.209 8 million tons in 1961 to 56.661 6 million ton, 19.960 4 million ton, and 12.083 3 million tons in 2019, respectively. India, China, Pakistan and other countries were major livestock producers, and the output of ruminants such as cattle and sheep ranked among the top 10 in the world. Its methane emissions are also increasing, and the increase is more and more rapid. On this basis, this article proposes that a multi-pronged approach can be taken to reduce methane emissions from animal husbandry. At the policy level, we should establish statistical data and measurement standards for methane emissions from animal husbandry, tax greenhouse gas emissions from animal husbandry or allow them to participate in the carbon market, establish an incentive mechanism to encourage farmers to reduce methane emissions from farms, and enhance the awareness of climate change among producers and consumers. At the production level, we should improve the quality of forage grass, adopt reasonable grazing management strategies, add feed supplements, optimize genetic selection, and improve the utilization level of livestock manure. At the consumer level, we should reduce the waste of meat and dairy and reduce or replace animal-based diets with plant-based diets as a combination of strategies to reduce methane emissions from animal husbandry.
    2022,41(3):124-130 , DOI: 10.13300/j.cnki.hnlkxb.2022.03.014
    Abstract:
    91 wild barley samples from the Near East,Central Asia and Tibet of China were selected and phylogenetically analyzed based on the alcohol dehydrogenase Ⅲ (ADH3) gene to study the genetic evolution relationship of barley.The results showed that the number of haplotypes (H=22) and genetic diversity (Hd=0.914,π=0.012 65) of the wild barley from Near East were significantly higher than that of the wild barley from Tibet (H=5Hd=0.753,π=0.012 16) and Central Asia (H=8,Hd=0.810,π=0.011 10).Ninety-one wild barley samples were mainly divided into two groups (Ⅰ and Ⅱ).81% of wild barley from the Near East and 80% of wild barley from Tibet were clustered in group Ⅰ. 91% of wild barley from Central Asian and a few parts of wild barley from the Near East and Tibet were clustered in group Ⅱ. The results of analyzing population structure further confirmed that the wild barley samples from Tibet were more closely related to wild barley from the Near East than to wild barley from the Central Asia.It is clarified the genetic evolution relationship of wild barley in the Near East,Tibet and Central Asia.It will provide the molecular basis for studying the origin of cultivated barley.
    2022,41(3):131-138 , DOI: 10.13300/j.cnki.hnlkxb.2022.03.015
    Abstract:
    Two CMS genes were truncated in different lengths,expressed in prokaryotic cells and genetically transformed in Arabidopsis thaliana and Brassica napus. to determine the relationship between the toxicity of the protein encoded by the ogu CMS sterility gene orf138 and male sterility and the core functional region of the hau CMS sterility gene orf288. The results of truncated male sterile gene orf138 showed that the growth of E. coli expressing pET32a1-138 and pET32a1-93 containing transmembrane helix was significantly inhibited after the IPTG was added,while the growth of E. coli expressing pET32a45-138 without transmembrane helix was not affected. It is indicated that the toxic region of ORF138 is located at the N-end containing the transmembrane helix. Results of genetic transformation showed that PS:Rfp13835-138 and PS:Rfp13845-138 did not cause male sterility in Arabidopsis thaliana and B. napus,indicating that the complete N end is necessary for ORF138 to induce male sterility in plants. The results of genetic transformation of different truncated orf288 in Arabidopsis thaliana showed that positive seedlings transformed with PS:Rfp288104-288,PS:Rfp288134-288 and PS:Rfp288164-288 were male sterile,while all the positive seedlings transformed with PS:Rfp288194-288 were fertile. It is preliminarily proved that the core functional region of orf288 is orf288164-288,indicating that the 164th-194th aa of ORF288 may be closely related to the cytoplasmic male sterility in hau.
    2022,41(3):139-145 , DOI: 10.13300/j.cnki.hnlkxb.2022.03.016
    Abstract:
    A F2 population of radish (Raphanus sativus L.) was constructed by crossing the lobed-leaf cultivar J4 with the serrated-leaf cultivar WA.Two bulk DNA samples consisted of equivalent amounts of DNA from 20 individuals with lobed-leaf and 20 individuals with serrated-leaf in the F2 population were used to study the inheritance of the lobed-leaf in radish.The results showed that the leaf in radish was controlled by a single gene.The lobed-leaf is incomplete dominant over the serrated-leaf.The gene for lobed-leaf was initially mapped to the genomic region from 0.07 Mb to 7.97 Mb on chromosome R7 through bulked segregant analysis (BSA) and genotyping by sequencing (GBS).It was found that there is good collinearity between 0.87-1.32 Mb in the candidate interval of radish and 16.35-16.80 Mb of the A10 chromosome of rapeseed by analyzing the collinearity between the whole genome of radish and rapeseed(Brassica napus).Gene function annotation of the collinear segment confirmed that Rs390250(899 863-901 651 bp) is a candidate gene of lobed-leaf in radish.This candidate gene encodes a HD-ZipⅠ (the class Ⅰ homeodomain leucine-zipper) transcription factor.Its non-synonymous mutation site T425C located in the 2nd exon leads to changes in conserved amino acids in the LZ (leucine zipper) domain,indicating that it may be a key site for the variation of leaf morphology.
    2022,41(3):146-156 , DOI: 10.13300/j.cnki.hnlkxb.2022.03.017
    Abstract:
    In order to further clarify the role of bacteria in pine wilt disease and control effect of emamectin benzoate and antibiotic mixture on the disease,strains, which can significantly promote survival and reproduction of nematode and aggravating the disease, were screened from bacteria carried by Bursaphelenchus xylophilus. High-efficiency antibiotics were screened from 30 kinds of antibiotics by testing their antibiotic activity to the screened disease-related bacteria, and the inhibitory effect of emamectin benzoate on the disease-related bacteria was studied. The toxicity of high-efficiency antibiotics and emamectin benzoate mixture to B. xylophilus and the control effect of the mixture on pine wilt disease of 6-month-old Pinus massoniana seedlings was determined by the immersion method and the root filling method, respectively. The results showed that compared with strains AMA3-2 and AMA3-3, strain AMA3-1 had a better promoting effect on the survival, reproduction of the nematode and the disease. Ciprofloxacin and minocycline had better antibacterial activity against AMA3-1, but emamectin benzoate had no inhibitory effect on AMA3-1. When the mixture or emamectin benzoate was 500 mg/L, the mortality rate of B. xylophilus could reach more than 80%. While the corrected mortality of B. xylophilus maintained at a low level (0.74%-2.43%) under the treatment of different concentration of high-efficiency antibiotics. When the concentration was 500 mg/L, and application time was 2 days before inoculation (on the day of inoculation) with the mixture of B. xylophilus and AMA3-1, the control effect of the mixture of emamectin benzoate and high-efficiency antibiotics on the disease was 50% (25%), while that of emamectin benzoate was 33% (17%) and high-efficiency antibiotics was 17% (0%). The results showed that emamectin benzoate or its mixture had high toxicity to B. xylophilus, but antibiotics had no killing effect. Under certain conditions, the mixture of emamectin benzoate and antibiotic can improve the control effect on pine wilt disease.
    2022,41(3):157-163 , DOI: 10.13300/j.cnki.hnlkxb.2022.03.018
    Abstract:
    In order to clarify the virus infection of lily in production,virus-infected lily samples collected from Yunnan and Zhejiang Provinces were analyzed by using high-throughput sequencing technique.Eight known viruses,including lily mottle virus (LMoV),cucumber mosaic virus (CMV),plantago asiatica mosaic virus (PlAMV),dahlia mosaic virus (DMV),figwort mosaic virus (FMV),rose yellow vein mosaic virus (RYVV),dahlia common mosaic virus (DCMV),and cassava vein mosaic virus (CsVMV),and two new viruses were identified through sequence alignment and assembly.Then 48 lily samples collected from Yunnan,Zhejiang,Jiangxi,Shanghai,Guangdong and Hunan Provinces were detected using reverse transcription polymerase chain reaction (RT-PCR).The results showed that DMV,RYVV,PlAMV and LMoV were predominant and the positive detection rates of them were above 95%.The positive rate of FMV was higher than 85%,while that of CMV was the lowest,which was only positive in the samples from Kunming,Yunnan Province.DCMV and CsVMV were not detected in these samples.The mixed infection rate of lily virus was 100%,and 3-6 viruses were positive in a single sample,with a total of 6 mix types.The mixed infection of lily virus in Kunming,Yunnan Province was the most complicated.A single sample from Kunming was infected with 5-6 viruses.These results indicated that the detection rate and the mixed infection rate of lily viruses were both high in the detected areas. Therefore, it is necessary to monitor and detect the viruses that infected lily plants as early as possible to prevent the transmission of viruses and avoid economic losses.
    2022,41(3):164-172 , DOI: 10.13300/j.cnki.hnlkxb.2022.03.019
    Abstract:
    Heterologous expression is an efficient approach to activate silent gene clusters of bioactive natural products.The rare actinomycetes strain Amycolatopsis sp.TNS106 is a producer of ristomycin A,which exhibits fast growth, short fermentation time and convenient genetic manipulation system.In order to develop this strain into a heterologous expression host for biosynthetic gene clusters (BGCs),the non-ribosomal peptide synthetase gene (rpsA) essential for the ristomycin A biosynthesis was replaced with a cassette containing the bacterial attachment sites attBΦC31 and attBΦBT1 via homologous recombination to construct a host with a clean background of secondary metabolism and two integrative sites.To test the obtained strain HXR1,integrative plasmids containing actinorhodin BGC from Streptomyces coelicolor or spinosad BGC from Saccharopolyspora spinosa were conjugated into HXR1.The results of fermentation and product analyses showed that actinorhodin and spinosad were successfully produced in HXR1.Compared with the Sac. erythraea?derived host LJ161 belonging to the non-Streptomyces actinomycete host,the actinorhodin production from HXR1 was approximately 1 day earlier and 1.3-fold higher.The Amycolatopsis sp.TNS106-derived host HXR1 will provide a useful platform for accelerating the discovery of novel secondary metabolites from Streptomyces and rare actinomycetes.
    2022,41(3):173-180 , DOI: 10.13300/j.cnki.hnlkxb.2022.03.020
    Abstract:
    The previous studies in authors’ group indicated that an endophytic Fusarium lateritium from the Nothapodytes pittosporoides (Oliv.) plant may promote the growth and disease resistance of potato.In order to expand the application scope of this strain,tomato,which is also a Solanaceae crop,was used to study the effects of F. lateritium on the growth and disease resistance.The results showed that the plant height of tomato increased by 1.15 times compared with the control group after 50 days of root-soaking treatment with F. lateritium.The content of chlorophyll a and chlorophyll b were 1.16 times and 1.47 times higher than that of the control group.The root biomass of the treatment was 1.38 times higher than that of the control,indicating that F. lateritium promotes the growth of tomato.The results of bioassay showed that the fusarium wilt disease index of tomato (45.16%) in the treatment group with F. lateritium was about 28.99% lower than that in the control group (74.15%),indicating that F. lateritium enhances the resistance of tomato to fusarium wilt.The expression patterns of key genes in the auxin synthesis,salicylic acid synthesis and jasmonic acid pathway of tomato were analyzed after 20,30 and 40 days of treatment.The results showed that the treatment affected the expression of key genes of plant hormones to different degrees.The GFP-labeled strain was further used for fluorescence colonization observation and the colonization rate was calculated by qPCR method.After 14 hours,the presence of F. hyphae was observed in the root system of tomato.The colonization rate of F. hyphae gradually increased with the extension of the treatment time within a certain period of time,indicating that F. lateritium can endogenously colonize the root system of tomato.In conclusion,it is speculated that F. lateritium can mediate the expression of phytohormone-related genes through the endogenous colonization in roots of tomato,thereby affecting the plant growth and disease resistance of tomato.
    2022,41(3):181-190 , DOI: 10.13300/j.cnki.hnlkxb.2022.03.021
    Abstract:
    Carotenoids are secondary metabolites and pigments widely existed in horticultural plants.They play an important role in the growth and development of plants and ornamental value.It is also a natural active substance with high-value, which is beneficial to human health.Therefore, the metabolic regulation of carotenoids has always been a research hotspot in horticultural plants.The differences in the components and contents of carotenoid are one of the important reasons for the diversity of color and nutritional value of horticultural plants.Analyzing the molecular mechanism of the formation of high-quality traits is the premise and basis for directional improvement.To date, the metabolic pathway of plant carotenoids has been clarified.A large number of studies have shown that mutations of promoters and coding regions in metabolic pathways are the key factors causing the diversity of carotenoid metabolism.This article reviewed the strategies of studying the genetic mechanism of carotenoid variation in horticultural plants, the types of variation in promoters and coding regions, and the effects of variation on carotenoid metabolism.It will provide a theoretical basis for the directional improvement of carotenoids in horticultural plants.
    2022,41(3):191-199 , DOI: 10.13300/j.cnki.hnlkxb.2022.03.022
    Abstract:
    Five different varieties of fresh tomatoes planted in the demonstration base of the Institute of Vegetable Research, Wuhan Academy of Agricultural Sciences were used to analyze the dynamic changes of fruit color, hardness, and quality indexes including vitamin C, soluble sugar, titratable acid, lycopene, and minerals during the ripening to explore the dynamic quality changes of fresh tomato during the growing period and to guide cultivation and establish suitable harvest period. The results showed that the hardness decreased from 3 000-4 000 g to 1 000-2 000 g, the peel red color gradually deepened, the lycopene increased to about 0.016 mg/g during the ripening of fruit. The content of soluble solids, vitamin C, glucose and fructose all showed a change pattern of first increase and then decrease, and reached the maximum value at the stage of hard-ripening. The sugar-acid ratio and soluble sugar generally showed a gradual upward trend. The content of soluble protein, titratable acid and malic acid showed a gradually decreasing trend. There were significant differences in the content of certain minerals in the same variety of tomato in different growth periods as well. It is indicated that the hard-ripening stage is the most suitable harvest period for fresh tomatoes. The sugar-acid ratio, the content of fructose and soluble protein of NT31 tomato areabout 7.5, 15.0 mg/g, 17.0 mg/g,respectively, which has higher nutritional and commercial values.
    2022,41(3):200-210 , DOI: 10.13300/j.cnki.hnlkxb.2022.03.023
    Abstract:
    In order to improve the prediction accuracy of dissolved oxygen in pond,and improve the lag of prediction results,this study proposed an improved long short-term memory (ILSTM) model based on empirical mode decomposition (EMD) and K-means clustering.A combination of Pearson correlation analysis and principal component analysis was used to extract features from the original data,EMD was used to decompose dissolved oxygen,and the selected environmental parameters were combined with each component of dissolved oxygen to generate a sample set to be clustered by K-means.The corresponding ILSTM prediction models were established for different decomposition components in the same kind,and the hyperparameters were selected by grid search,five-fold cross-validation and early stop method.The dissolved oxygen in the future 1 h pond was predicted and compared with models of LSTM,ILSTM,LSTM-SVR,EMD-LSTM,and EMD-ILSTM.The results showed that the RMSE,MAE and MAPE decreased by 50.46%,63.20% and 68.96%,respectively,compared with the LSTM model,which proved that the ILSTM model could alleviate the prediction lag of the traditional LSTM model.Compared with ILSTM model,RMSE,Mae and MAPE of EMD-ILSTM model,decreased by 53.22%,46.74% and 38.19% respectively,which proved that EMD Algorithm can improve the prediction accuracy.The RMSE,MAE and MAPE of the EMD-KILSTM model were 0.109 9 mg/L,0.074 9 mg/L and 9.327 8%,respectively,and its RMSE,MAE and MAPE decreased by 4.35%,7.42% and 8.09%,respectively,compared with the EMD-ILSTM model,which proved that K-means clustering could improve the prediction accuracy and the EMD-KILSTM model was the best one among the compared models.The above results show that the EMD-KILSTM model can deeply analyze the characteristics of dissolved oxygen from both time scale and historical environmental categories,and has higher prediction accuracy and better generalization ability,which provides scientific basis for intelligent water quality control.
    2022,41(3):211-220 , DOI: 10.13300/j.cnki.hnlkxb.2022.03.024
    Abstract:
    In order to explore the molecular characteristics of the interleukin-22 (IL-22) gene in channel catfish (Ictalurus punctatus) and its response to different pathogenic microorganisms,the coding sequence (CDS) of IL?22 was cloned by PCR amplification,and the distribution of IL?22 mRNA in different tissues and under different stimulate were monitored by quantitative real-time PCR (qRT-PCR).The results showed that the CDS of IL?22 was 534 bp in length and encoded 177 amino acids.Multiple alignment and analysis of amino acid sequence showed that IL?22 was highly conserved in evolution of fish and vertebrates.qRT-PCR results showed that IL?22 was widely distributed in 10 tissues of channel catfish,with the highest expression in the hindgut and the lowest in the heart.After stimulation for 24-48 h,IL?22 was up-regulated by Poly(I:C) and LPS stimulation,and down-regulated by PHA and PMA stimulation in the channel catfish kidney cells.The bacteria,virus injection and cypermethrin immersion experiments showed that the expression of IL?22 in the gill,skin,hindgut,spleen,trunk kidney and head kidney was up-regulated overall.The above results showed that the expression patterns of IL?22 in different tissues under different stimulate are different,and this gene can participate and play a key role in mucosal and various immune responses.
    2022,41(3):221-228 , DOI: 10.13300/j.cnki.hnlkxb.2022.03.025
    Abstract:
    The two-component system (TCS) FlrBC mutant strains ΔflrB and ΔflrC were constructed via homologous recombination using Aeromonas hydrophila ZYAH72 as the wild-type strain. Then,differences in polar-flagellum synthesis,swimming motility,biofilm formation,exopolysaccharide secretion,adhesion ability and the resistance against whole-blood killing of the above strains were compared to investigate the function of FlrBC in A. hydrophila. The results showed that similar to the wild-type strain,both ΔflrB and ΔflrC could form polar flagellum,and there was no significant difference in swimming motility. However,crystal violet staining test revealed that the biofilm formation capacity of ΔflrB and ΔflrC decreased by 27.2% and 22.3%,respectively. The result of Congo red test showed that compared with the wild-type strain,the exopolysaccharide secretion of ΔflrB and ΔflrC decreased by 18.4% and 14.2%,respectively. The qRT-PCR results showed that the deletion of flrB and flrC inhibited the gene expression of flagellar synthesis and biofilm-related pathway. After co-incubation with grass carp CIK cells,the adhesion rate of ΔflrB and ΔflrC decreased by 23.2% and 18.2% respectively compared with the wild-type strain. The results of whole blood killing assay showed that the ability of ΔflrB and ΔflrC to resist whole blood killing was significantly reduced. The above results show that TCS FlrBC is not required for the formation of polar flagella in A. hydrophila,but plays a regulatory role in bacterial flagella assembly and biofilm formation,and affects the pathogenicity of A. hydrophila.
    2022,41(3):229-235 , DOI: 10.13300/j.cnki.hnlkxb.2022.03.026
    Abstract:
    In order to investigate the deodorization effect of ozone flotation rinsing on silver carp surimi, the surimi were prepared by conventional rinsing and ozone flotation rinsing,respectively. The volatile components of surimi were determined by the electronic nose combined with headspace-solid phase micro-extraction-gas chromatography (HS-SPME-GC-MS). The ROAV analysis was used to determine the extent of contribution of specific volatile components to the odour of the silver carp surimi in order to find the source of its fishy odour. The results showed that a total of 24 volatile substances were detected in the silver carp surimi. The volatile components were less in surimi by ozone floatation rinsing than those by conventional rinsing. The relative content of fishy components were reduced, such as hexanal, heptanal, nonanal, decanal and 1-octene-3-ol,but 1-methyl-4-nitromethyl-piperidine and 5-methyl-2-phenyl-indole which are associated with the fishy odour, were not detected. The PCA analysis result of the electronic nose was consistent with the HS-SPME-GC-MS results. In conclusion, ozone flotation rinsing of surimi can effectively reduce the fishy odour of surimi compared with conventional rinsing, and the rinsing time should be controlled in the range of 10-15 min.
    2022,41(3):236-243 , DOI: 10.13300/j.cnki.hnlkxb.2022.03.027
    Abstract:
    The effects of different recovered sarcoplasmic proteins (SP) (HSP,recovered by heating flocculation; PHSP,recovered by pH-shifting flocculation; PHCSP,recovered by pH-shifting/chitosan flocculation) on the protein denaturation,protein oxidation,lipid oxidation and gel performance of sliver carp surimi during the freeze-thawing cycles were studied. The results showed that the addition of SP recovered by different methods all could inhibit the decrease of salt-soluble protein content,Ca2+ -ATPase activity,total sulfhydryl content and the increase of surface hydrophobicity of freeze-thawed surimi.And HSP showed the best performance among these three SP.The results of protein carbonyl content showed that the addition of SP could protect surimi from protein oxidation during freeze-thaw cycles.However,compared with pure surimi,the thiobarbituric acid-reactive substances (TBARs) value and pH value of the surimi added with different recovered SP did not change significantly.In addition,with the increase of the number of freeze-thaw cycles,the gel quality of surimi deteriorated seriously.PHCSP could protect the sliver carp surimi from the gel degradation of freeze-thaw treatments.
    2022,41(3):244-251 , DOI: 10.13300/j.cnki.hnlkxb.2022.03.028
    Abstract:
    Grass carp (Ctenopharyngodon idellus) in two farming modes were selected as materials,the differences between the muscle quality (color,texture,and cooking loss),nutritional components (composition of amino acids and fatty acids),and flavor properties (free amino acids,free fatty acids,nucleotide and its degradation products,and volatile aroma compounds) were analyzed to explore the influence of aquaculture mode on the nutritional quality and eating quality of grass carp. Compared with ordinary pond farming,planting grass farming improved the color,textural properties,water holding capacity and mouthfeel of grass carp muscle. The muscle from grass carp cultured by planting grass contained higher essential amino acids and n-3 PUFA and n-6 PUFA,enhancing the nutritional quality of grass carp. Additionally,the contents of odorous compounds such as 1-hexanol,nonanal,1-octen-3-ol and octanal were significantly lower in grass carp cultured by planting grass than those in the grass carp cultured in ordinary pond. Moreover,the contents of amino acids with umami and sweet tastes were higher in grass carp cultured by planting grass,improving the edible quality of grass carp. In conclusion,grass carp cultured by planting grass owned better nutritional and edible qualities than that by ordinary pond farming.
    2022,41(3):252-260 , DOI: 10.13300/j.cnki.hnlkxb.2022.03.029
    Abstract:
    A liquid particle counter was developed with electrical resistance method and a method of detecting heavy metal Cu2+ combined with the click chemistry method to solve the problems including the complicated operation,long cycle of detection and high cost of detection existed in the current methods of detecting heavy metals in water quality. A model for identifying the particle size and a model for particle counting were established. A particle counting software based on LabVIEW was developed. A rapid method of detecting Cu2+ in water was realized by using polystyrene microspheres as detection probes and particle counters as detection platforms. The results showed that the relative error of particle size identification and particle counting was less than 5% and 10%,indicating that the accuracy of particle counting meets the requirements. When the concentration of Cu2+ was 10-1 000 μmol/L,there was a good linear correlation between the number of polystyrene microspheres and the concentration of Cu2+. The average recovery rate was between 87.85% and 101.08%. The detection limit was 2.29 μmol/L. The time of detection was about 4 min. Compared with the traditional method of detecting Cu2+,the method of detecting Cu2+ with a liquid particle counter based on the electrical resistance method has the advantages of simple operation,fast speed of detection,high sensitivity and low cost of detection.
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    Abstract:
    Antibiotic resistance genes (ARGs) in the aquatic environment have become one of the global health problems, and swine farm is an important source in the environment. However, related research is still in its infancy and needs more in-depth and detailed research. In this paper, we start from different swine treatment methods (activated sludge method, anaerobic biological treatment method, constructed wetland method, physical and chemical method), the distribution and removal effect of ARGs in the sewage treatment process of pig farms are mainly introduced. The physical and chemical method is the most promising way to deal with ARGs pollution in swine breeding environment. The researchers also gain insight into treatments that have the potential to reduce the abundance of ARGs in swine wastewater. We summarize the occurrence and transmission routes of ARGs in the process of swine breeding. And we analyze the distribution, migration and transformation of antibiotic resistance genes in different treatment processes of swine wastewater and clarifies the influencing mechanism of environmental factor on the transmission of ARGs. Finally, we put forward for three suggestions of ARGs in swine wastewater.
                                                                                                                   
    Abstract:
    In order to investigate the effect of pile-turning interval on ARGs and MGEs in continuous composting of ectopic fermentation bed , two conditions of turning over once 1 d (F1 group) and 2 d turning once (F2 group) were set. Fifteen target genes, including 2 tetracycline (tetG, tetW), 3 sulfonamide (sul1,sul2,dfrA1), 2 β-lactamse (blaTEM-1,fexA), 2 MLSB (ermX, ermQ), 2 FCA (optrA, IsaE) and 1 aminoglycoside (aac(6?)-Ib-cr),1 integrase (intI1) and 2 transposon (Tn916/1545, ISCRI) genes, were identified by PCR in composting process; while 7 genes with high detection rate (tetG, tetW, sul1, sul2, blaTEM-1, ermQ, intI1) were quantitatively detected by qPCR. The PCR results showed that, 11 kinds of ARGs (tetG, tetW, sul1, sul2, blaTME-1, fexA, ermX, ermQ, optrA, IsaE, aac (6?)-Ib-cr) and 3 kinds of MGEs (intI1, Tn916/1545, ISCRI) were detected in both groups, in which the detection rates of 7 genes (tetG, tetW, sul1, sul2, blaTME-1, ermQ、intI1) were higher; 12 species from 0 to 5 d, 1 species at 33 d in F1 and 40 d in F2, increased significantly after 40 d, indicating that the species of ARGs and MGEs changed with the change of temperature. qPCR results showed that the total relative abundance of 7 target genes in both groups show a trend from rise to decline during the experiment, at the end,decreased by 82.33% and 78.89% compared with 0 d in F1 and F2, respectively; among which the relative abundance of tetG、tetW、sul1、blaTEM-1、ermQ and intI1 was decreased by 16.51%、87.89%、54.58%、>99.99%、97.80%、59.29% and 64.32%、99.46%、50.91%、99.29%、82.22%、99.92%. The results showed that the types and relative abundance of ARGs reduced during degradation manure and sewage at high temperature period in ectopic fermentation bed, and the removal efficiency of most ARGs was better by turned over once every two days.
                                                                                                                   
    Abstract:
    In order to explore the effect of aging process on the antioxidant activities of Pericarpium Citri Reticulatae ‘Chachi’ (PCR-C), the fresh peel, aging for 1 year and 10 years were taken as the experimental objects to extract and purify to obtain flavonoids extracts (PCR-CF), and then the changes of flavonoids contents were analyzed through using HPLC. The antioxidant activities of PCR-C were evaluated by using tert-butyl hydroperoxide (t-BHP)-induced oxidative damage in human hepatoma cells (HepG2 cells) as the model, and the molecular mechanism of antioxidant activity was further explored via real-time fluorescence quantitative PCR (qRT-PCR) and Western blot. The results showed that, during storage for 10 years, the contents of hesperidin exhibited decreasing trend. In contrast, the contents of Polymethoxyflavones (PMFs) and total PMFs showed increasing trends and PCR-C10F had the highest contents in which the total PMFs content of PCR-C10F was (98.66±0.56) mg/g. Moreover, under the oxidative damage of HepG2 cells induced by t-BHP, PCR-CF from different storage years could significantly increase the levels of SOD and GSH and reduce the contents of MDA, and there was significant difference between different storage periods. The antioxidant activity of PCR-C10F was the strongest, in which SOD level reached (139.38±17.38) U/mgprot, GSH level reached (117.81±3.22) μmol/gprot, MDA level reached (0.39±0.03) nmol/mgprot, and there was no difference to the normal control group (p>0.05). Correlation analysis further indicated that nobiletin was the main active component that PCR-C10 maintained the redox balance. Furthermore, PCR-C10F significantly up-regulated the mRNA expression levels of Nrf2 (p<0.001) and increased the expression levels of Nrf2 (p<0.05) in nuclear protein. Then, the mRNA (p<0.001) and protein (p<0.01) expression levels of NQO1, SOD1, GSTO1 and GSH-Px were significantly activated, and the mRNA (p<0.001) and protein (p<0.05) expression levels of HO-1 was significantly decreased. In conclusion, during aging process, the contents of PMFs in PCR-C showed increasing trends and the antioxidant activities enhanced and PCR-C10F can play a protective role against oxidative stress through regulating the Nrf2-ARE antioxidant signal pathway, which provided a theoretical basis for rational storage and quality control of PCR-C.
                                                                                                                   
    Abstract:
    In order to further reduce the detection time and achieve rapid customs clearance of import and export food, it is necessary to develop the technology of simultaneous rapid detection of multiple toxins. Due to the interaction between probe and analyte, it is difficult to quantify the existing scheme of fixing multiple detection lines on a single test paper, and single quality control line cannot guarantee the effectiveness of multiple channels, and the real "synchronous" detection is not achieved. In this paper, two kinds of horizontal and vertical arrays adapted to colloidal gold lateral flow immunoassay (LFIA) strips were designed and constructed by 3D printing technology, with four channels synchronous detection capability. The LFIA strip of aflatoxin B1 (AFB1), zearalenone (ZEN), ochratoxin A (OTA) and deoxynienol (DON) was integrated into the array and applied to the detection of corn, corn meal and wheat kernel. The detection limits (LOD) of the four toxins were 0.031 ng/mL, 0.19 ng/mL, 0.78 ng/mL, 0.22 ng/mL, respectively. The recoveries ranged from 74.42% to 112.40%. There was no cross-reaction. This study provided a kind of equipment supporting for highly sensitive, simultaneous and rapid detection of multiple mycotoxins with great application potential.
                                                                                                                   
    Abstract:
    In order to explore the effect of cellulose-degrading bacteria on the decomposing and nitrogen loss of compost, the experiment mixed the carcasses of livestock and poultry with straw after high temperature treatment, and divided them into the control group without adding bacterial agent and adding 1% high temperature resistant cellulose bacteria (Parageobacillus thermoglucosidasius). The compost was composted by aerobic static ventilation for 28 days, and the physical and chemical parameters (temperature, pH, moisture content, ammonium nitrogen, nitrate nitrogen, nitrite nitrogen, total carbon and total nitrogen) and nitrogen conversion function during the composting process were determined. Changes in gene copy number and the effect of adding inoculants on nitrogen conversion were analyzed. The results showed that the ammonium nitrogen content and nitrate nitrogen content of the bacterial agent group were significantly higher (P<0.05) than the control group, but the final total nitrogen content of the bacterial agent group was lower than the control group. The copy number of nirK in the control group in the pre-composting period was significantly higher than that in the inoculum group (P<0.05) and was significantly positively correlated with the content of NH4+ (P<0.05); the copy number of nirS in the inoculum group was extremely significantly higher than that in the control group (P<0.01), and has a very significant positive correlation with NO3- content (P<0.01). In the middle stage of composting, the copy number of narG in the control group was significantly higher than that in the inoculum group (P<0.01), and the correlation with NH4+ content was close to the significant level (P=0.064); in the late stage of composting, the copy number of nosZ in the control group was extremely significantly higher than bacterial agent group (P<0.01). The high temperature-resistant cellulose-degrading bacteria mainly change the nitrogen cycle of the compost through ammonia oxidation and denitrification in the early stage of composting and affect the nitrogen loss.
                                                                                                                   
    Abstract:
    The effect of pesticide residues on the nutritional quality of pakchoi has been studied by applying low, medium and high concentrations of pesticides (chlorothalonil, chlorpyrifos and fipronil) to pakchoi. The effects of different washing and cooking methods on removing pesticide residues in pakchoi were compared. The results showed that the contents of water, soluble protein and nitrate all decreased firstly and then increased with the increase of the application concentration; there were no significant differences in vitamin C contents and carotenoid contents between the different treatment groups(P> 0.05); the contents of reduced sugar, calcium and phosphorus increased firstly and then decreased compared with the blank group; the crude fiber content of high concentration group increased. Detergent had the best removal effect for all the three pesticides, alkali water and rice washing water soaking was the second, and salt water and clear water was the last. The thermal stability of chlorothalonil is poor, and the removal percentages of three cooking methods for chlorothalonil were all above 94%; 60℃ blanching and 100℃ boiling for chlorpyrifos had lower removal effect, while hot oil stir-frying could significantly improve the removal effect; the removal effect of stir-frying was the best for fipronil, followed by blanching and boiling.
                                                                                                                   
    Abstract:
    Due to the differences of fruits' own sizes, their brix prediction models have poor robustness and low prediction accuracy, so it is important to eliminate the effects brought by the differences of fruit sizes to improve the accuracy of fruit sorting models. The NIR spectra of apples with different fruit diameters were collected by an online NIR spectroscopy detection device, and the partial least squares (PLS) models of apple brix (SSC) were established after various pre-processing of the spectra, and then the modeling sets in the apple fruit diameter group 75 mm-85 mm were used to predict the prediction set samples in the apple fruit diameter group 65 mm-75 mm and 85 mm-95 mm, respectively. The modeling and prediction sets in the fruit diameter groups of 65 mm-75 mm, 75 mm-85 mm, and 85 mm-95 mm were used as the modeling and prediction sets of the mixed apple size brix prediction model, respectively, and the model was simplified by using the feature spectral selection algorithm. The correlation coefficient Rp was increased from 0.805 to 0.943, the root mean square error value RMSEP was reduced from 0.778 to 0.480, and the RPD was increased from 0.96 to 3.05 compared with the optimal set of apple brix prediction models established when the modeling set and the prediction set had different fruit diameters, and then the established generic model was simplified to reduce Due to the influence of apple size on the apple brix model, the model prediction performance can be improved.
                                                                                                                   
    Abstract:
    Three pesticides (chlorothalonil, chlorpyrifos and fipronil) in pakchoi were sampled and quantitatively determined by sampling rate calibrated in vivo solid-phase microextraction technique combined with gas chromatography. The absorption, enrichment and dissipation behavior of pesticides in pakchoi were studied. The results showed that the in vivo detection method was accurate, sensitive, rapid and convenient. Light and temperature could promote the degradation of three pesticides in pakchoi. Compared to pakchoi cultured in water, both the absorption rates and degradation rates of pakchoi cultured in soil for three pesticides were faster by foliar spraying. Postharvest storage also had an effect on the degradation of pesticides. Storage temperature had little effect on the dissipation rate of chlorothalonil, while low temperature could inhibit the dissipation of chlorpyrifos and fipronil. This study provided an analytical method for tracking pesticides in living plants and provided an insight into the environmental behavior in complex biological systems. It was also helpful to better understand the characteristics of pesticide residues in pakchoi and to reduce the potential health risks in human.
                                                                                                                   
    Abstract:
    In order to study the correlation between feeding behavior and growth performance of breeding pigs, this paper conducted correlation analysis on 5 feeding traits (daily feed intake, single feed intake, feeding rate, daily feeding length and daily feeding frequency) and 4 growth traits (daily weight gain, feed conversion ratio, breeder"s age to 100kg and backfat thickness) of 101 Duroc breeding pigs, constructed a prediction model of breeder"s age to 100kg, and developed an information system integrating breeder"s performance measurement trait calculation, feeding behavior analysis and equipment remote monitoring. The feeding traits with significant correlation with growth rate were selected according to Pearson correlation, and the partial least squares regression (PLS) prediction model was established for breeding pigs up to 100 kg body weight at day of age, and the cross-validation results showed that the mean coefficient of determination R2 of the PLS model was 0.68, the mean absolute error MAE was 3.2d, and the Spearman correlation was 0.796 (P<0.01). On this basis, based on web technology, B/S (Browser/Server) front and back-end separation architecture was selected, the front-end was based on Reactjs technology stack, and the back-end used flask web framework and MySQL database to develop the breeder performance measurement information management system. Through breeding test, it was proved that each functional module operated stably and the prediction model could predict the test breeder up to 100kg weight day, with R2 of 0.53 and MAE of 5.3d.
                                                                                                                   
    Abstract:
    To explore the effects of setting time before molding on the quality and microstructure of noodle-shaped surimi product-fish vermicelli (FV), the morphologic, cooking characteristics, textural properties, sensory attributes, and microstructure of FV and dynamic rheological properties of fish paste processed under different setting time at 4 ℃, 15 ℃, and 25 ℃. The results showed that setting treatment significantly improved the cooking characteristics, textural properties, and sensory scores of FV at lower material temperatures (p<0.05), including an increase of 20.18% and 9.94% in water-holding capacity, 28.97% and 24.11% in tensile strength of FV for 8 h and 4 h at 4 ℃ and 15 ℃, respectively. However, there was no significant difference in the quality of FV within 0.5 h at 25 ℃ (p>0.05). Meanwhile, the proper setting time promoted the protein dissolution in the fish paste and then formed a dense gel network with more starch trapped in the network. Nevertheless, the fish paste formed a weak gel during long setting time, and the subsequent squeezing process would destroy the existing structure and reduce the continuity of the gel network, which eventually led to the degradation of FV quality. In summary, the maximum setting time of fish paste at material temperatures of 4 ℃, 15 ℃, and 25 ℃ was 8 h, 4 h, and 0.5 h, respectively, and excessive setting would lead to the deterioration of FV quality and microstructure.
                                                                                                                   
    Abstract:
    In order to optimized the air frying condition of fried flavored fish cake, the samples were prepared by air frying, and the quality changes of fried flavored fish cakes were investigated under different frying temperatures(160℃, 180℃ and 200℃) and times(4 min, 6 min, 8 min and 10 min). With the increase of frying temperature and the extension of frying time, the L* value significantly decreased, the a* and b* values significantly increased and the surface of fish cakes obtain gold color. In the range of 160℃ to 180℃, the sensory quality of fish cakes gradually increased with the extension of frying time, while the sensory quality of fish cakes increased and then decreased at 200℃. Under frying temperature at 200℃ and fried for 8 min, the appearance of fish cake fried by air frying was similar to fried fish cake by deep-frying, which endowed fish cakes with flavor and texture of fried food. In addition, the moisture content of fish cake significantly decreased, the hardness and chewiness of fish cakes increased and the degree of lipid oxidation deepened with the extension of frying time at 200℃, which led to the decrease of product quality. Compared with the traditional fried fish cakes, the fish cakes fried by air frying at 200℃ for 8 min had unique fried flavor and color, and the fat content and malondialdehyde content were lower than traditional fried food.
                                                                                                                   
    Abstract:
    In order to comprehensively evaluate the germplasm resources of Allium macrostemon Bunge with excellent traits, high amino acid content and good flavor quality, six morphological traits such as plant height, leaf length and bulb diameter of A. macrostemon from different origins in Guizhou were compared. At the same time, the content of 17 free amino acids in its bulbs was determined by HPLC and analyzed for amino acid taste properties and principal components. The results showed that the six traits of plant height, bulb diameter, leaf length, leaf width, mid-plant width and root beard length of A. macrostemon were significantly different among the 9 populations (P<0.05), with coefficients of variation greater than 10%; Euclidean distance clustering analysis could cluster the 9 populations into 2 categories, and the morphological traits of category II were more prominent; the principal component analysis showed that the cumulative contribution of the first principal component reached 80.967%, and the comprehensive evaluation showed that the Qiannan population had the highest overall score. The average total free amino acid (TFAA) content of each population was 6 078.522 mg/kg, with higher TFAA content in Qiandongnan (10 365.90 mg/kg) and Guiyang (8 174.55 mg/kg) populations; Flavor intensity value TAV>1 indicated that the amino acid contributed to the flavor of the samples, and bitter Arginine (TAV=6.81) was the main factor affecting the flavor of A. macrostemon the main factor. Principal component analysis showed that the cumulative contribution of the first four principal components reached 90.144%, and the highest overall score was obtained by the Qiannan population. In conclusion, there are regional differences in morphological traits and flavoring amino acid content of A. macrostemon, with the Qiannan population having outstanding morphological traits and the Southeast population having excellent flavoring quality, and these two populations have high exploitation value.
                                                                                                                   
    Abstract:
    Rice-crayfish co-culture system is a successful model of the coupling development of green rice and green aquatic products. In order to explore the symbiotic mechanism of rice and crayfish, the field distribution characteristics of crayfish in high-frequency distribution sampling area (GP), low-frequency distribution sampling area (DP) and none-crayfish control area (CK) were studied by cage capture method, combing with the investigation of soil properties, diseases, pests and weeds in rice field and the analysis of rice yield, to study the ecological effects of rice-crayfish co-culture system. The results showed that there was a significant positive correlation between the distribution quantity of crayfish in paddy field and the water depth, and the univariate linear regression equation was y = 197.69x-25.77; The high frequency distribution of crayfish can improve the soil structure, significantly reduce the soil bulk density of 0~10 cm by 6.25%~11.76%, and significantly increase the total capillary porosity of 0~10 cm soil layer by 8.08%~10.78% (P < 0.05); The high frequency distribution of crayfish significantly increased the content of organic matter in 0~10 cm soil by 6.24%~10.30%, significantly increased the soil microbial biomass carbon in 0~20 cm soil layer (P < 0.05), and significantly inhibited the growth of weeds; Different distribution frequencies of crayfish have no significant effects on diseases and pests, rice yield and its components, but the yield tends to increase with the increase of distribution frequency. Therefore, in order to promote the green and sustainable development of ecological planting and breeding of rice and crayfish, different distribution frequencies (water depth) of crayfish can be properly distinguished by management and research in terms of production and scientific research.
                                                                                                                   
    Abstract:
    In order to optimize the farming system and promote the annual production potential and income and the resource utilization of crop production in paddy field of Eastern Hubei, a fixed field experiment was continuously conducted for 4 years to test the differences in the annual productivity, economic benefit, the utilization of resources such as radiation, temperature, nitrogen (N) and phosphorus (P), and N and P contents in the soil of 6 double cropping patterns, including oilseed rape- maize (O-M), oilseed rape- rice (O-R), oilseed rape- water-saving and drought-resistant rice (O-WDR), wheat- maize (W-M), wheat- rice (W-R), and fallow- double season rice (F-DR). The results showed that, the annual economic yield of W-R pattern was the highest, followed by O-R pattern. The average annual production benefit of O-R pattern was the highest. The highest uptake rate of N was found in O-R and W-R patterns; while, that of P was found in O-M pattern. The highest utilization efficiencies of radiation and temperature resources were found in F-DR pattern. After 4-round experiment, the N surplus was highest but N loss lowest in the soil of O-R pattern; while the P surplus was highest but P loss lowest in the soil of O-M pattern. The oilseed rape- rice plantation pattern had higher and stable productivity, good production benefit, and better maintenance of soil N fertility and lower N loss risk from farmland; therefore, it has an application potential to replace the conventional F-DR pattern in Eastern Hubei.
                                                                                                                   
    Abstract:
    To screen the labor-saving and light simplified cultivation patterns suitable for large-scale orchards of Newhall navel oranges, three different cultivation patterns of newhall navel orange were selected: traditional cultivation pattern, wide-row and narrow-plant pattern, wide-row and narrow-plant fence pattern, and the quality analysis of fruits under the canopy was carried out. The results showed that the quality of single fruit in the general cultivation pattern was significantly greater than that of the two innovative patterns, and the quality of the upper single fruit reached 339.42 ± 70.28g. If the hierarchical differences are not considered, the fruit shape index of the wide-row and narrow-plant pattern reached 1.08 ± 0.057, which was significantly greater than that of the wide-row and narrow-plant fence pattern and the general cultivation pattern, and the fruit juice yield of the wide-row and narrow-plant fence pattern reached 51.07% ± 3.84%, which was significantly higher than that of the wide-row and narrow-plant fence pattern and the general cultivation pattern. In the wide-row and narrow-plant pattern, the single fruit quality of the upper canopy reached 233.53 ± 53.01g, which was significantly greater than that of the middle and lower layers; the soluble solids in the upper layer was significantly higher than that of the middle layer and the lower layer; the thickness of the peel in the middle layer was the largest, reaching 0.52 ± 0.079cm, which was significantly larger than that of the lower layer; the fruit juice yield of the lower layer was the highest, the content of fruit Vc was the lowest; the titratable acid of the middle layer was the highest, and the solid acid ratio was the lowest. In the wide-row and narrow-plant fence pattern, the juice yield of the upper layer is lower than that of the lower layer, and the single fruit quality of the middle layer is the largest, and the thickness of the upper layer is significantly higher than that of the middle and lower layers. In the general cultivation pattern, the single fruit quality and peel thickness are larger, there is no significant difference between the upper, middle and lower layers, and the fruit shape index of the lower layer is the smallest; the soluble solid content is low, and the difference between the upper, middle and lower layers is not significant; the solid acid ratio of the middle layer is the lowest; the Vc content of the lower layer is significantly lower than that of the upper and middle layers; and the fruit juice yield of the middle and lower layers is significantly higher than that of the upper layer. The cultivation pattern had a significant impact on the fruit quality, mainly in the quality of single fruit, the thickness of the peel, the soluble solids, the solid acid ratio, the juice yield, and the Vc content; the canopy layer did not have a significant impact on the fruit quality of the wide-row and narrow-plant fence pattern, and had a greater impact on the wide-row and narrow-plant pattern and the general cultivation pattern.
                                                                                                                   
    Abstract:
    In order to explore the changes of soil microbial community structure under different continuous cropping years of tobacco, the changes of soil nutrients, microbial diversity, community structure and driving factors of four different types of tobacco planting soils in Shangluo area, the hinterland of Qinling Mountains were analyzed. The results showed that the contents of soil organic matter, total nitrogen, available phosphorus, available potassium and pH decreased with the increase of continuous cropping years; The richness and diversity of bacteria decreased significantly. The dominant bacteria were Actinobacteriota, Proteobacteria, Chloroflexi, Acidobacteriota and Firmicutes. The richness of fungi increased significantly. The dominant bacteria were Ascomycota, Basidiomycota and Mucoromycota. Under the condition of Y4 continuous cropping, the relative abundance of beneficial microorganisms in soil decreased, such as Firmicutes and desulfurization bacteria, and the relative abundance of pathogenic microorganisms increased, such as Trichoderma and Trichoderma. Long term continuous cropping will lead to the gradual reduction of soil nutrient content and pH value, and then affect the structure of soil microbial community, reduce the relative abundance of beneficial microorganisms and increase the relative abundance of pathogenic microorganisms, and then increase the risk of tobacco disease. Therefore, establishing a good farming system or constructing microbial community is the key technical way to alleviate or solve the imbalance of microbial community structure in continuous cropping tobacco field.
                                                                                                                   
    Abstract:
    The aroma of fruit is an important sensory attribute that affects consumer’s preference. In this study, firstly, gas chromatography-mass spectrometry (GC-MS) analysis was applied to profiling volatiles in three commonly marketed pears including ‘Korla’, ‘Xuehua’ and ‘Huangguan’ pears, results showed that, 50, 48, and 37 volatile substances were detected respectively in the pear fruits respectively. The main volatiles belong to alkanes, terpenes and fatty acids, accounting for about 85% of the total volatile compounds. ‘Korla’ is dominated by fatty acids and aldehydes, ‘Xuehua’ is dominated by terpenes, and ‘Huangguan’ has the lowest content of various substances. Then, a 15-person sensory panel was formed to conduct a flash profiling analysis on the fruit aroma quality of the three pear cultivars, the results showed that ‘fruity’ of all cultivars was the most intense sensory attribute while ‘sour’ was the lowest. Among ‘Korla’ pears, only the sweetness properties are significantly higher than ‘Xuehua’ pears, and the aroma properties except for lotus mist are significantly higher than that of ‘Huangguan’ pears. Subsequently, correlation analysis between sensory scores and volatile compounds showed that 8 volatiles, including dimethyl glutarate, eugenol, 2-undecenal, 2-ethyl-3-hydroxyhexyl-2-methylpropanoate and 3-methylene-1-oxa spiro [4.5] Decan-2-one was significantly correlated with various sensory attributes including ‘floral’, ‘green’ and ‘fruity’. The joint analysis of sensory evaluation and metabolites helps to find out the key compounds which affect the fruit flavor, thus can provide a theoretical basis for flavor quality breeding of pear in the future.
                                                                                                                   
    Abstract:
    QTL mapping for internode diameter of reciprocal second internode and reciprocal third internode by R/qtl with the CIM method was performed using the G46B/A232 RIL populations and the high-density genetic linkage map created by resequencing the populations. In chromosomes 2, 3, 4, 7, and 11, there are 3 QTLs and 7 QTLs for internode diameter of reciprocal second internode and reciprocal third internode. Among them, qRSID2-1 and qRTID2-1 were close to each other, and qRSID2-2/qRTID2-2 and qRTID2-3 may be the same QTL; they have been detected in several trials, with phenotypic contribution rates ranging from 7.89% to 12.36% and physical distances less than 100 kb on chromosome 2. The genetic study for internode diameter of reciprocal second internode and reciprocal third internode in rice provides a basis for the fine mapping of internode diameter QTL, which is conducive to the molecular breeding and germplasm innovation of rice varieties with lodging resistance and ideal plant type.
                                                                                                                   
    Abstract:
    Alternate wetting and drying irrigation (AWD), as an important water-saving irrigation technique, has significant impacts on grain yield, water and nitrogen use efficiencies, and quality of rice. The positive or negative effect of AWD on rice is mainly determined by the degree of soil drying. In this paper, the mechanisms underlying influences of AWD on rice yield, water and nitrogen use efficiencies, and quality were reviewed from the aspects of soil physicochemical and biological characteristics, rice root morphological and physiological traits, and aboveground agronomic and physiological characteristics. Meanwhile, the effect of interaction between AWD and nitrogen fertilizer on rice yield, water and nitrogen use efficiencies, and quality were briefly introduced, and the existing problems and future research were also discussed. Such a review aims to provide theoretical basis for the breeding with high yield, high efficiency, and good quality and its cultivation regulation in rice.
                                                                                                                   
    Abstract:
    Deoxynivalenol (DON) widely exists in grains (such as wheat, rice, and corn), which seriously threatens human health. Therefore, we constructed a chemiluminescent fiber optic immunosensor for rapid field detection of DON in grains by using a combination of biosensing recognition and chemiluminescence technology. Further, a portable sensing platform was integrated into a 32 cm × 15 cm × 25 cm cassette, weighing less than 3 kg, for chemiluminescence signal detection. The results showed that the constructed chemiluminescence optical fiber immunosensor exhibited a good linear relationship between 0.1-1200 ng/mL, and the detection limit was 62.7 pg/mL The functionalized optical fiber probe could be stored stably for 30 days and had good specificity and anti-interference. The recovery rate of DON applied to grain samples was 81.00 %-107.33 %, and the relative standard deviation was less than 8.69 %. Compared with ELISA, the sensitivity was increased by 30 times, and the linear range was broadened by 3 orders of magnitude, which is suitable for on-site rapid detection of DON in grain samples.
                                                                                                                   
    Abstract:
    In order to obtain surimi products with low oil and malondialdehyde content and good sensory properties, fish cakes were prepared by two-step heating. The effects of the second-step heating methods (deep-frying, air-frying, pre-frying + air-frying, frying and roasting) on the sensory quality and other physical and chemical indicators of fish cakes were studied. The results show that the fish cakes had golden color, and the moisture loss, oil and malondialdehyde content of fish cakes significantly increased after the second-step heating. Although air-frying fish cakes had lower sensory scores than deep-frying fish cakes, they were lower in oil and malondialdehyde content. What's more, the texture properties and flavors of air-frying fish cakes were closed to those of deep-frying fish cakes. In summary, air frying could not only reduce the oil and malondialdehyde content of fish cakes, but also impart the fried flavor and taste of fish cakes. It is a better alternative to replace the traditional frying method.
                                                                                                                   
    Abstract:
    Ammonium is a major inorganic nitrogen source for plants, however when its presence is too high plants will suffer from ammonium toxicity, with the understanding of how plants tolerant ammonium is important to improve both the nitrogen use efficiency and yield. In order to understand the potential mechanisms of ammonium toxicity and tolerance, this article reviewed the important research progress from three aspects: the ammonium source for plants, the mechanisms of ammonium toxicity and tolerance. We summarized that the rhizosphere and apoplast acidification caused by ammonium uptake and assimilation is a major reason for ammonium toxicity and plants can alleviate ammonium toxicity by their intrinsic mechanisms or by adding other nutrients, meanwhile we provided prospects for the future research. It is expected to provide theoretical reference to achieve ammonium tolerant and nitrogen use efficient genetic improvement.
                                                                                                                   
    Abstract:
    In view of the problems of high cost, long time and technical difficulty in the extraction and synthesis of messenger molecule (pp)pGpp, a new in vitro synthesis technology was established and optimized based on the existing in vitro enzymatic synthesis of (pp)pGpp. This method achieves the goals of high efficiency, convenience, safety and environmental protection, and low cost. The results showed that high purity (pp)pGpp can be obtained by reacting (pp)pGpp synthases: RelA, GppA and YvcI in 25 mmol/L Tris-HCl pH 9.0, 15 mmol/L MgCl2, 100 mmol/L NaCl at 37 °C for 30 minutes, and further purified by anion exchange (pp)pGpp molecule. Compared with the traditional direct extraction from bacteria or plants and the existing in vitro enzymatic preparation process, this method has the advantages of simple operation, rapidity, low cost, and environmental friendliness, and can meet the needs of downstream biochemical analysis and structural biology experiments. More importantly, it provides a material basis for microbial signaling pathways and the development of new antibacterial drugs.
                                                                                                                   
    Abstract:
    为研究Leo百脉根(Lotus corniculatus L.)C2钙依赖蛋白激酶基因LcC2DP1在百脉根不定根形成过程中的功能,通过RACE法从百脉根中克隆LcC2DP1基因,利用qRT-PCR检测其时空表达模式,并通过农杆菌介导的瞬时表达系统在百脉根中过量表达LcC2DP1并鉴定其功能。结果显示,LcC2DP1基因全长705 bp,编码235个氨基酸,分子质量为25.95 ku,与蒺藜苜蓿同源性最高(82%);在百脉根不定根分化过程中持续表达,表达部位为根、茎和叶片;和野生型亲本(WT)相比较,转LcC2DP1基因百脉根(TP)的不定根分化提前1~2天;在不定根分化9~15天,其总根长分别是WT的168%、155%,根体积分别是WT的249%、161%,根尖数分别是WT的156%、137%。TP百脉根的总根长(P<0.01)、根体积(P<0.01)和根尖数(P<0.05)表现出一定的发育优势,表明LcC2DP1基因可能与不定根发育调控相关。
                                                                                                                   
    Abstract:
    To study the effects of magnesium(Mg) fertilizer on fruit yield and quality of Satsuma Mandarin (Citrus unshiu Marc.), so as to provide a theoretical basis for the rational application of Mg fertilizer. The experiment was set up in 2017, with 20-yr-old Satsuma Mandarin trees in Yiling District, Yichang City, Hubei Province. Five treatments were designed as CK, T1, T2, T3 and T4, Mg application doses were MgO 0, 100, 150, 200 and 250 g/tree each year. The sugar and organic acid contents of pulp, and fruit colouration were determined at fruit turning color period and fruit maturity from 2019 to 2020. Compared with treatments without Mg applications, Mg fertilizer significantly increased the fruit yield of Satsuma Mandarin, and the fruit yield increased first and then decreased with the increase of Mg fertilizer dosage. In 2019 and 2020, the fruit yield was the highest when the Mg fertilizer dosage was 124 g MgO / plant and 122 g MgO/ plant, respectively. At the fruit turning color period, Mg application increased the sucrose content in the pulp , significantly increased the L, a, b and C values of pericarp, significantly reduced the H value, chlorophyll a, chlorophyll b and total chlorophyll contents of pericarp, improved the brightness, chroma and purity of pericarp. However, there was no significant effect on sugar and acid contents of pulp, the L,a, b, C values and chlorophyll content of the peel during fruit maturity. The results of principal component analysis showed that the fruit internal and external quality of T2, T3 and T4 treatment was better, while the fruit quality of T4 treatment was better from the perspective of principal component score.The Mg application rate of Satsuma Mandarin with the highest yield and better quality is 122~150 g MgO/plant, and the Mg application rate for the best quality is 200~250 g MgO/plant.
                                                                                                                   
    Abstract:
    Fertilizer application is an important part of rice production, which not only affects rice yield, but also may cause environmental pollution, therefore, it is important to carry out research on precision variable fertilizer application technology. To realize real-time monitoring of fertilizer application accuracy, a hinged lever type fertilizer box discharge monitoring system, which can actively monitor the remaining fertilizer quantity of fertilizer box in real time, is designed on the self-designed rice direct seeding synchronous side depth fertilizer application machine. The monitoring system consists of a weighing device and a multiplexed fertilizer discharge monitoring device. The weighing device consists of hinged lever frame, balance beam load cell, etc. The parallel beam load cell is used as the working element to carry the fertilizer box installed above the hinged lever mechanism and the real-time fertilizer gravity inside the fertilizer box. The multi-circuit fertilizer discharge monitoring part consists of the controller, fertilizer discharge monitoring, data communication, monitor, etc. It collects the fertilizer discharge signals obtained from each load cell and transmits them to the monitor interactive interface after processing, so that the operator can easily view and configure the operational parameters of the fertilizer application system in real time. The results of the field test showed that the maximum relative error of monitoring was 4.79% and the minimum was 3.55%.This monitoring system is combined with the fertilizer discharge volume monitoring system based on the rotation of the fertilizer discharge shaft, which can realize the real-time autonomous adjustment of fertilizer discharge volume of the fertilizer applicator and can provide reference for the research of intelligent fertilizer application technology and equipment.
                                                                                                                   
    Abstract:
    For the application of deep learning in the field of Chinese herbal medicine, especially southern medicine, the complex background will reduce the recognition accuracy. if the complex network structure is used, which requires high arithmetic power to support the training and detection, which is difficult to satisfy the embedded or mobile devices in practice and affects the real-world detection effect. In that case, this study proposes to improve the EfficientNetV2 network model to classify and recognize eight southern medicine leaves in the complex background collected in the field. The main work is to redesign the network structure, adjust the scope of the Fused-MBConv and MBConv architectures, replace some 3×3 convolutional kernels with 5×5 convolutional kernels to increase the perceptual field size, reduce the number of convolutional layers of the network, and further reduce the network complexity. The Transfer learning is introduced to train the model. The adaptive moment estimation optimization algorithm is selected to optimize the hyperparameters through multiple tests to determine the learning rate. MultiMarginLoss is selected as the loss function to solve the problem of complex background information affecting the recognition accuracy. In addition, to improve the stability of the model training process, this study increases the diversity of the data set by adopting affine transformation, Gaussian blur and other data augmentation methods on the experimental data set to avoid the model over-fitting problem. The experimental results show that the improved model can achieve 99.12% accuracy in recognizing the image of southern medicine leaves with complex backgrounds, which is 1.17% more accurate than the baseline model EfficientNetV2-S, and the parameters size are reduced by 85% approximately. The average training time is reduced by 47.62%. Compared with DenseNet121, ShuffleNet, and RegNet, which are also lightweight models, the improved model has significant advantages in model storage space, accuracy, and training time. Experimental results show that the proposed model performs well in multi-species southern medicine leaf classification task. The lightweight degree and performance of the model were further improved.
                                                                                                                   
    Abstract:
    The purpose of this study was to compare the nutritional and flavor characteristic differences between local native chicken and commercial broiler, Gushi chicken raised in plains, Honglashan chicken raised in plateaus and Cobb broiler raised in commercial cage were selected as the research objects, and the nutritional components, amino acid composition, fatty acid composition and volatile flavor substances of leg muscle were systematically compared and analyzed. The results showed that chicken breeds had an impact on the nutritional characteristics and flavor quality of chicken meat. The fat content of Gushi chicken was 16.13 g/100g, which was significantly higher than that of the other two varieties (P<0.05); the sugar content of Honglashan chicken reached 0.97 g/100g (P<0.05), the content of essential amino acids and polyunsaturated fatty acids was in the middle, which were 29.79 g/100g and 35.91 mg/g, respectively; Cobb broiler contained 83.91% protein, 31.94 g/100 g of essential amino acids, and 42.76 mg/g polyunsaturated fatty acids, which were significantly higher than those of the other two breeds (P<0.05). The relative contents of low-threshold aldehydes in Gushi chicken, Honglashan chicken and Cobb broiler were 40.08%, 49.09% and 36.46%, respectively. In conclusion, Gushi chicken and Honglashan chicken had better flavor quality, while Cobb broiler had better nutritional properties.
                                                                                                                   
    Abstract:
    In view of the high labor intensity of water chestnut harvesting and the lack of harvesting machines that can be used in practical production, combined with the soil conditions of water chestnut planting field and the existing manual harvesting methods, a self-propelled water chestnut harvester for harvesting with water is designed in this paper. The machine is composed of walking system, transmission system, rotating disturbance device, lifting and separation device, collection device, etc. It can complete the excavation, fruit and soil separation, lifting and collection of water chestnut at one time. The walking system is composed of track chassis. Each track is independently driven by a hydraulic motor, which can realize differential steering and in-situ steering. Two hydraulic motors are the same model and driven by a hydraulic double pump, which can ensure the straight running stability of the track chassis. This design can improve the working performance of the track chassis and is more suitable for walking in the water chestnut planting field. This machine is equipped with a 16.2 kilowatt water-cooled diesel engine as the power source of the whole machine. The transmission system of the whole machine is divided into hydraulic transmission part and mechanical transmission part. The hydraulic transmission part provides power for the walking system of the harvester and the digging and harvesting device, which can realize the walking speed control of machines, the height adjustment of the digging and harvesting device, the speed control of the rotating disturbance device and the speed control of the lifting and separation device. The mechanical transmission part can provide a stable speed difference between the rotating disturbance rollers at all levels and the lifting and separation device to ensure the smooth progress of the harvesting process; the three-stage rotating disturbance roller forms a rotating disturbance device to realize the full disturbance and mixing of soil and water; the toothed digging shovel and lifting chain form a lifting and separation device to complete the excavation, fruit and soil separation and lifting of water chestnut fruits. The performance of the track chassis of this type of water chestnut harvester is theoretically analyzed. The results is that the theoretical minimum steering radius of chassis differential steering is 1.5 m, and the theoretical steering radius of in-situ steering is 1.0 m; The theoretical value of the uphill limit overturning angle is 55.63°, and the theoretical value of the downhill limit overturning angle is 55.08°. Theoretical analysis shows that the machine has small turning radius and large ultimate overturning angle, which is very suitable for the working environment of water chestnut planting field. The field test results show that under the experimental conditions, the maximum driving speed of this type of water chestnut harvester on the field road is 0.97 m/s, the minimum steering radius of differential steering is 2.1 m, the in-situ steering radius is 1.3 m, the maximum climbing angle is 24.2°, the fruit digging rate is 53.19%, and the damage rate is 4.21%, which can meet the performance requirements of water chestnut mechanized harvesting to a certain extent.
                                                                                                                   
    Abstract:
    The effects of four symbiotic fungi including three arbuscular mycorrhizal fungi (AcaulosporaSscrobiculata, DiversisporaSspurca, and D.Sversiformis) and an endophytic fungus (Piriformospora indica) on fruit quality and soil characteristics of eight-year-old lane late navel orange grafted on trifoliate orange were studied. The results showed that the symbiotic fungi promoted the rate of root fungal colonization and also significantly increased fruit set, flesh weight and fruit weight per fruit, and reduced fruit hardness. These fungi also increased fruit coloration value, polar and equatorial diameter, glucose, fructose and sucrose content to varying degrees, dependent on the fungal species. In addition, the symbiotic fungi significantly increased soil aggregate stability (MWD), organic carbon (SOC), Olsen-phosphorus, and glomalin-related soil protein (GRSP) contents, whereas reduced available potassium content. Correlation analysis revealed that root fungal colonization was significantly and positively correlated with fruit sugar components, soluble solids, easy-to-extract GRSP, MWD, SOC and Olsen-phosphorus. In a comprehensive analysis, D. spurca was the most effective in promoting fruit appearance, sugar content, and soil structure and fertility.
                                                                                                                   
    Abstract:
    Four kinds of citrus peel residue dietary fibers (Navel orange, Apple pomelo, Orah and Lemon) were prepared by enzymatic hydrolysis to explore the performance differences of different citrus dietary fibers and improve the comprehensive utilization rate of citrus by-products. The fiber morphology was characterized by scanning electron microscope, Fourier transform infrared spectroscopy and X-ray diffraction, and the physicochemical properties and antioxidant activity in vitro were determined. The comprehensive quality of different citrus fibers was evaluated by principal component analysis. The results showed that there were variety differences in the properties of citrus fiber prepared by enzymatic method, the total fiber content of Lemon fiber (67.63 ±0.46%) was the highest, the proportion of Navel orange fiber was the best, the hydration property and antioxidant activity of Orah and Navel orange fiber were the strongest, and Apple pomelo fiber showed the highest apparent viscosity among the four fibers. The order of comprehensive evaluation from high to low is Navel orange fiber, Orah fiber, Apple pomelo fiber and Lemon fiber. The results can provide theoretical reference for citrus dietary fiber as a potential food additive resource and comprehensive utilization of citrus peel residue.
                                                                                                                   
    Abstract:
    As a kind of non-hazardous treatment process, thermophilic aerobic fermentation can effectively transform the body of dead pigs into an organic resource, achieving the pollution-free recycle for dead pigs from breeding industry. However, some odor pollutants would be emitted out, due to continually performed chemical reactions in this process. In fact, the emission regularity of odor pollutants in a fermentation process generally would be different, if different kinds of fermentation additives are added, which tend to be agricultural waste, even the other conditions are same. Hence, this work was designed where minced dead pig was taken as raw fermentation materials, maize stovers(T1), rape stovers (T2), sawdust (T3), rice bran (T4) were taken as fermentation additives to explore the differences caused by different fermentation additives in the emission regularities of main odor pollutants and the total odor intensity of emitted gases. The fermentation tests were arranged in a 10 L fermentation tank which was heated by interlayer water bath, making inside temperature controlled at 60 ℃. The interior was equipped with a stirring device and the ventilation rate was kept at 8 L/(L.min). Totally 5 tests were conducted and each stayed for 72 hours. For each of tests, a certain kind of fermentation additive and BM strain would be mixed in 1.2±0.2 kg minced dead pig to fermentate, according to the wet weight ratios of 1:5.5 and 1:100 respectively except no fermentation additive was used in the control check. In each a test totally 14 times sampling would be performed according to a fixed interval. During from 0 to 6th hour the interval was 3 hours but converted to 6 hours during 6th hour to 72th hour. In a single sampling, 500 ml emitted gas as a sample was collected from treatment tanks to a tube, and this action would be repeated for 3 times. For each a sample, the components of odor pollutants were analysed, the concentration of which also were detected, meanwhile the concentrations of ammonia and carbon dioxide were also detected. And multiple comparisons of total odor intensity of different treatments were conducted separately to determine the effects of additive types on total odor intensity during the thermophilic aerobic fermentation of dead pigs. Finally, the results showed: 1) after 5 thermophilic aerobic fermentation tests for dead pig, 40 odor pollutants in total were detected 18 of which could be accurately detected qualitatively and quantitatively—including 3 sulfur compounds,1 alkane compound, 12 aromatic hydrocarbon compounds, 1 phenolic compound and 1 inorganic compound. Among that, 7 odor pollutants were identified as the main source of odor, containing 3-ethyltoluene, 4-ethyltoluene, p-cresol, methanethiol, dimethyl sulfide, dimethyl disulfide and ammonia. 2) The use of additives accelerated the process of thermophilic aerobic fermentation of dead pigs, these treatments with maize stovers and rice bran increased the carbon dioxide emission, and these treatments with rape stovers and sawdust reduced the carbon dioxide emission. 3) With different additives added, the detected total odor intensity of emitted gas were different—the increasing order was T3, T2, T1, T4 and CK in view of the amount of total odor intensity, which also illustrated that the use of additives could inhibit the odor emission to some extent. While sawdust had the best effect thanks to the total odor intensity of 4241.08. Therefore, this work would be a theoretical reference that sawdust could be an effective and prospective additive for thermophilic aerobic fermentation of dead pigs.
                                                                                                                   
    Abstract:
    Aiming at the problem that the truss structure of caterpillar type rape windrower"s header was complicated, which caused the header to vibrate greatly, a multi-objective topology optimization of the frame structure of the header was carried out based on the variable density method to reduce the vibration of the header under different working conditions. Hypermesh software was used to establish the topology optimization model of the header, the compromise programming method was used to define the comprehensive objective function of static stiffness and dynamic frequency of the header, and the weight of each sub-object was determined according to the analytic hierarchy process (AHP). Based on the multi-body dynamics method, a recurdyn-based virtual prototype model of rape windrower was established. The dynamic loads of the moving pair of the header were obtained under parts debugging conditions, transport conditions and field operation conditions. The ideal material density distribution of the spatial structure of the header was obtained under the constraints of volume fraction and maximum loads of the moving pair. Considering the practical engineering application, the optimized header frame is normalized. The finite element model of the optimized header frame was established, and the finite element static analysis and modal analysis were carried out, and the vibration amplitude at the measuring point of the header before and after optimization was compared. The comparison results show that the maximum stress value decreases from 107.99MPa to 65.45MPa, and the maximum deformation decreases from 0.82mm to 0.36mm.The natural frequency of the first three orders is increased to 24.187Hz.The actual vibration test results show that after optimization, the vibration amplitude of each measuring point of the header decreases, and the amplitude of the longitudinal cutter support decreases from 4.83m/s2 to 1.49m/s2, and the overall vibration of the header decreases. The research can provide reference for the structural improvement and optimization of rape windrower.
                                                                                                                   
    Abstract:
    Given the lack of domestic freshwater fish head processing equipment and the low degree of mechanization of fish head processing, taking Hypophthalmichthys molitrix as the research object, the head processing device of Hypophthalmichthys molitrix based on machine vision is designed in this paper. The head processing device of Hypophthalmichthys molitrix is composed of a fish body conveying device, fish body image acquisition device, fish body turnover part, vertical clamping conveyor belt, fish head cutting part, fish head sectioning part, device control system, and so on. The fish body image acquisition device obtains the fish body image on the conveying device and calculates the fish head cutting path; The fish body enters the vertical clamping conveyor belt through the fish body turnover part and moves forward under the action of the vertical clamping conveyor belt; When the fish body reaches the fish head cutting position, the vertical clamping conveyor belt stops after adjusting the fish body position, the fish head cutting part cuts the fish body according to the fish head cutting path and resets, and the vertical clamping conveyor belt drives the fish head forward; The cut fish head is a section in half through the fish head sectioning part. Taking Hypophthalmichthys molitrix as the research object, the performance test of the prototype is carried out. The results show that after the fish head is cut, the determination coefficients of the linear fitting between the actual horizontal distance from the upper cutting point and the lower cutting point and the predicted horizontal distance are 0.911 and 0.985 respectively, and the root means square errors are 6.31mm and 2.61mm respectively; The detection time of fish head cutting path is 0.055 ± 0.009s, the processing time of fish head is 13.28 ± 0.35s, and the appearance score of the fish head is 0.88 ± 0.02, which meets the production requirements of the Hypophthalmichthys molitrix head processing. This research can provide new methods and equipment for the Hypophthalmichthys molitrix head processing industry, and provide theoretical and methodological references for the automatic processing of the head of Hypophthalmichthys molitrix.
                                                                                                                   
    Abstract:
    Ponkan (Citrus reticulata), an important loose-skin tangerine in China, is very popular among consumers. Fruit thinning is an approach widely used for promoting fruit quality in the cultivation process, but the cost of manual thinning is increasingly higher due to the shortage of labor. Therefore, it is urgent to find a labor-saving way for thinning fruit in a more efficient manner. In this study, we used ‘Egan No. 1’ Ponkan as the material to explore the effect of mechanical pruning-mediated fruit thinning on improving fruit quality. At the same time, the expression patterns of genes associated with sucrose and citric acid metabolism were analyzed. The results showed that fruit thinning speed and efficiency were substantially accelerated by mechanical pruning, leading to prominent saving of labor. In addition, mechanical pruning-mediated fruit thinning significantly increased the transverse diameters, longitudinal
                                                                                                                   
    Abstract:
    扩展蛋白具有松弛细胞壁的功能,在植物生长发育及逆境应答中发挥重要作用。为了揭示甜樱桃中扩展蛋白基因的结构与功能,本文克隆了甜樱桃PavEXPA2基因,并分析了该基因在甜樱桃不同组织中及逆境胁迫(干旱和盐)下的表达情况。结果表明,PavEXPA2基因cDNA全长序列为1035 bp,开放阅读框(ORF)为852 bp,编码283aa,蛋白等电点为8.90,分子质量约为30.81kD,含有两个跨膜螺旋结构和一个信号肽,亚细胞定位预测该基因定位于细胞壁;组织表达分析显示,PavEXPA2基因在甜樱桃易脱落组织中表达量较高,如盛开花朵,即将脱落的果柄、果实、叶柄等,其中在即将脱落的叶柄中表达量最高;在干旱胁迫下,相对于未处理样品,干旱处理后的样本PavEXPA2表达量上升,在处理6h时表达量达到最高,随后降低;盐胁迫条件下,PavEXPA2表达量呈先下降后上升再下降的趋势,其中在处理6h时表达量达到最高。本研究对PavEXPA2基因的研究可以为阐明其在甜樱桃生长发育中的功能奠定理论基础。
                                                                                                                   
    Abstract:
    In order to determine the best process parameters of thermophilic aerobic fermentation of dead pigs, the orthogonal experiment of thermophilic aerobic fermentation of dead pigs was carried out with dead pigs as fermentation raw materials and sawdust as additives, the additives ratios, fermentation temperature and ventilation rate as experimental factors, and the losses of carbon and nitrogen and the total odor intensity as experimental indexes. Analyze the components of odor substance in the exhaust gas, the concentration of which also were detected, meanwhile the concentrations of ammonia and carbon dioxide were also detected. The effects of additives ratios, fermentation temperature and ventilation rate on carbon and nitrogen losses and odor emission were analyzed by range and contribution rate analysis methods. Finally, the results showed: 1) after thermophilic aerobic fermentation tests for dead pig with sawdust as additives, 29 odor pollutants in total were detected 18 of which could be accurately detected qualitatively and quantitatively—including 3 sulfur compounds,1 alkane compound, 12 aromatic hydrocarbon compounds, 1 phenolic compound and 1 inorganic compound. Among that, 5 odor substances were identified as the main source of odor, containing p-cresol, methanethiol, dimethyl sulfide, dimethyl disulfide and ammonia. 2) the order of the factors influencing the losses of carbon and nitrogen in turn was additives ratios>ventilation rate>temperature. and that for the total odor intensity in turn was temperature> additives ratios> ventilation rate. 3) Taken the losses of carbon and nitrogen and the total odor intensity into consideration, the best technical parameters of thermophilic aerobic fermentation of dead pigs: the additives ratios is 1:5.5, the fermentation temperature is 55 ℃, and the ventilation rate is 14 L/(L.min). This process not only has the fewer loss of carbon and nitrogen, but also has the superiority for inhibiting the odor emission. Therefore, this work would be a theoretical support for the optimization of thermophilic aerobic fermentation process of dead pigs.
                                                                                                                   
    Abstract:
    Yuhuang Pomelo (C.grandis Osbeck)is a local citrus variety grown in Jianshi County, Hubei Province. To provide a scientific basis for the harvest of the fruit and the choice between seeded and seedless in production, the appearance and its internal quality of fruits among various harvest periods of different types were compared and analyzed. The results showed that the peel coloring degree and soluble solid content of fruits harvested 240 days post anthesis was comparatively highest. Meanwhile, the seeded type demonstrated the lowest titratable acid content and the highest solid-acid ratio (by 14.62), while the seedless fruit on the 222 days post anthesis had the highest solid-acid ratio (by 14.55). In general, the appearance and flavor quality of seeded fruit harvested 240 days post anthesis was the best, followed by those harvested 222 days post anthesis. The content of Vc (by 35.98 mg/ 100g in seeded type, 31.77 mg/100g in seedless type) and main volatile substance Germacrene D (by 382.32μg/g in seeded type, 279.41μg/g in seedless type) in seeded fruit were significantly higher than those in seedless fruit 240 days post anthesis. It indicates that timely harvesting and pollination can optimize the fruit quality of Yuhuang Pomelo, so scientific harvesting and increasing pollination rate can be used to increase orchard revenue.
                                                                                                                   
    Abstract:
    In order to explore the influence of agitator parameters in piglet milk mixing tank on milk mixing effect, a double-layer paddle piglet milk mixing tank was designed. The research method of CFD numerical simulation and response surface analysis was adopted. The speed, layer spacing, blade angle and distance from the bottom were taken as the design optimization parameters, and the mixing power, mixing time and average temperature were taken as the response indexes, The orthogonal simulation experiment of four factors and three levels is designed, the regression model of response index is established, and the optimal parameters of double-layer paddle agitator are obtained. The results show that the speed and blade angle have a significant impact on the mixing power, the speed, layer spacing, blade angle and distance from the bottom have a significant impact on the mixing time, the speed has a significant impact on the average temperature, the layer spacing and blade angle have a significant impact on the average temperature, and the speed has the greatest impact on the performance of the agitator; The response surface regression model has good fitting. The optimal parameter combination obtained by the response surface regression model is the speed of 80 rpm, the layer spacing of 170 mm, the blade angle of 30 °, and the distance from the bottom of 100 mm. Compared with that before optimization, the stirring power is reduced by 27.08%, the mixing time is reduced by 70.15%, and the average temperature is increased by 9.57%, and the turbulent flow energy cloud diagram distribution and temperature cloud diagram distribution are significantly better than those of the primary model. The results can provide theoretical basis and reference for the design and application of stirrer in piglet milk preparation tank.
                                                                                                                   
    Abstract:
    During manipulation of the steering wheel by the tractor operators, there are problems including intense vibration and unclear vibration transmission characteristics. Based on it, The ISO 5349 evaluation method was applied to evaluate the hand-transmitted vibration of the steering wheel system under two different conditions, and analyze the vibration transmission characteristics of arm systems of operators at different percentages. The results demonstrated that the daily vibration exposure of the tractor was 4.257 m/s2, which exceeded the limit of daily vibration exposure of 3.5 m/s2 regulated by the national standard, posing a risk of hand-arm vibration disease; steering wheel vibration in the axial direction was greatly higher than that in the tangential and radial directions, which was the main factor causing hand-transmitted vibration; radial vibration was largely absorbed during the transmission from the hand back to the forearm, while tangential vibration was greatly absorbed in the transmission from the forearm to the upper arm; moreover, the smaller the operator's physical size, the greater the vibration transmission rate at the hand back; significant increase in vibration from the hand back to forearm was found under the frequency of 20Hz. Therefore, in engineering practice, smaller operators should pay attention to the vibration protection at the palms, while larger ones are suggested to focus on the vibration protection at the wrists. Furthermore, the vibration protection at wrist should emphasize the radial direction, the vibration protection at elbow may highlight the tangential direction.
                                                                                                                   
    Abstract:
    For achieving the regulation of target products in the preparation of bio-oil by hydrothermal treatment of dead pigs, microwave-conventional two-step hydrothermal treatment for the preparation of bio-oil from different models of dead pigs and its related characteristics were studied in this paper. The results showed that the ratio of protein (P), lipid (L) and carbohydrate (C) was 5:20:1 and 20:5:1, the bio-oil yield showed an increasing trend and then decreased with the increase of the terminal conventional hydrothermal temperature. When P:L:C was 12:12:1, the bio-oil yield continued to increase with the increase of conventional hydrothermal temperature. The interaction of three components in a certain proportion can promote the production of bio-oil. Generally, under the same reaction conditions, the higher heating value (HHV) of bio-oil of model pigs with higher lipid content was relatively higher, and the interaction of the three components on the HHV of bio-oil was related not only to the proportion of components but also to the reaction temperature. The TN conversion rate of bio-oils of the three modes of dead pigs reached the maximum value at 260 ℃, and that of aqueous phase products reached the maximum value at 280 ℃. It was feasible to regulate the migration of N element to improve the quality of bio-oil. The bio-oil only prepared by microwave hydrothermal treatment in the experimental group with P:L:C of 5:20:1 has the largest comprehensive combustion characteristic index of 8.22×10-7 K-3.min-1. The increase of lipid content can improve the comprehensive combustion performance of hydrothermal bio-oil.
                                                                                                                   
    Abstract:
    Abstract: In order to comprehensively study the physical parameters of discrete element simulation of fish feed, hard pellet 3.0 and expanded floating feed 3.0 medium feed were selected as the research objects. The intrinsic parameters of the two feeds were measured by density measurement test and uniaxial compression test, The results showed that the density, elastic modulus, shear modulus and Poisson's ratio of hard pellet feed and expanded floating feed were 1096 kg?M-3, 336.32 MPa, 126.65 MPa, 0.33 and 626.7 kg?m-3, 85.98 MPa, 33.08 MPa and 0.3 respectively; The discrete element models of two kinds of feed were established; The contact parameters between the two kinds of feed and nylon plate and steel plate were determined by bounce test, inclined slip test and rolling test. The results showed that the collision recovery coefficient, static friction coefficient and rolling friction factor of hard pellet feed and steel plate, hard pellet feed and nylon plate, expanded floating feed and steel plate, expanded floating feed and nylon plate were 0.38, 0.538, 0.028, 0.405, 0.356, 0.033, 0.667, 0.566, 0.043, 0.688, 0.266 and 0.048 respectively;Based on the response surface optimization method of Box-Behnken test, the optimal contact parameter combination between hard pellet feed and hard pellet feed and between expanded floating feed and expanded floating feed are obtained. Through the stacking angle test, the collision recovery coefficient, static friction coefficient and rolling friction coefficient between hard pellet feed and hard pellet feed are 0.36, 0.246 and 0.126, and the collision recovery coefficient, static friction coefficient and rolling friction coefficient between expanded floating feed are 0.376, 0.26 and 0.131; The self-developed baiting machine is used for experimental verification. Taking the distributed coefficient of variation CV as the experimental index and comparing the measured value with the simulation value, it is obtained that the relative error of the hard pellet feed test index is1.709%, and the relative error of the expanded floating feed test index is1.077%, indicating that the discrete element model and the calibrated physical parameters of the two feeds can be used in the discrete element simulation test. It provides a theoretical reference for the design and structural optimization of baiting machine.
                                                                                                                   
    Abstract:
    Genome-wide association analysis (GWAS) is based on high-throughput sequencing technology, combined with bioinformatics and statistical methods, to identify genetic variants affecting complex traits at the genome-wide level. It is the most powerful and effective research method to study the genetic variation of complex agronomic traits and diseases, and its core is to study the association between genetic variation and target traits. This study briefly introduces the basic principles, processes and influencing factors of GWAS, and summarizes a series of progress made by GWAS in the research on tea beverage consumption, important agronomic traits of tea plant, the quality of tea and tea plant population structure. The problems encountered and the future development direction are expected to provide a basis for further research on the selection of tea consumers, the genetics and breeding of tea plant using GWAS.
                                                                                                                   
    Abstract:
    As the origination of tea plant and the largest tea producing country in the world, China has a long breeding history and profound research foundation. Clonal tea cultivars and cuttage propagation technology firstly appeared in China, and the largest number of tea cultivars in the world have been bred. After reform and opening up, genetics and breeding research have being accelerated in China. Many achievements have been made in the number and diversity of bred cultivars, breeding techniques and breeding basic theories, especially in tea plant whole genome sequencing and assembly, functional genomics areas led related field in the world and supported the high quality development of Chinese tea industry. In this review, we summarized the history and achievements of tea plant genetics and breeding in China, analyzed the weaknesses of tea research in heredity rules of major traits, breeding technology and breakthrough variety innovation. In view of these problems, we put forward some research priorities on the innovation of basic theories of genetics and breeding, breeding technology and cultivar in the future, for the sake of providing valuable reference for tea plant genetic breeding research.
    Display Method:
    2015,34(4):108-113, DOI:
    [Abstract] (2006) [HTML] (0) [PDF 1.06 M] (10247)
    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.
    2015,34(4):120-124, DOI:
    [Abstract] (2334) [HTML] (0) [PDF 976.50 K] (8796)
    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.
    2013,32(4):48-54, DOI: 1000-2421(2013)04-0048-07
    [Abstract] (2113) [HTML] (0) [PDF 1.58 M] (7266)
    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.
    2015,34(3):8-12, DOI:
    [Abstract] (1601) [HTML] (0) [PDF 3.41 M] (6191)
    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.
    2012,31(1):16-22, DOI: 1000-2421(2012)01-0016-07
    [Abstract] (2574) [HTML] (0) [PDF 1.07 M] (5724)
    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.
    2015,34(1):128-135, DOI:
    [Abstract] (2432) [HTML] (0) [PDF 1.21 M] (5705)
    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.
    2013,32(5):124-133, DOI: 1000-2421(2013)05-0124-10
    [Abstract] (1618) [HTML] (0) [PDF 4.01 M] (5458)
    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.
    2014,33(2):139-144, DOI: 1000-2421(2014)02-0139-06
    [Abstract] (1479) [HTML] (0) [PDF 968.56 K] (5092)
    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.
    2012,31(5):569-573, DOI: 1000-2421(2012)05-0569-05
    [Abstract] (1447) [HTML] (0) [PDF 912.59 K] (4988)
    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. 
    2012,31(1):127-132, DOI: 1000-2421(2012)01-0127-06
    [Abstract] (1734) [HTML] (0) [PDF 930.13 K] (4972)
    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.
    2016,35(1):81-85, DOI:
    [Abstract] (1183) [HTML] (0) [PDF 943.32 K] (4775)
    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.
    2014,33(06), DOI:
    [Abstract] (992) [HTML] (0) [PDF 8.30 M] (4654)
    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.
    2014,33(01):12-17, DOI: 1000-2421(2014)01-0012-06
    [Abstract] (1671) [HTML] (0) [PDF 944.55 K] (4633)
    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.
    2015,34(3):134-141, DOI:
    [Abstract] (1396) [HTML] (0) [PDF 1.42 M] (4631)
    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.
    2014,33(2):15-21, DOI: 1000-2421(2014)02-0015-07
    [Abstract] (1919) [HTML] (0) [PDF 980.62 K] (4627)
    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.
    2011,30(5):613-617, DOI: 1000-2421(2011)05-0613-05
    [Abstract] (1530) [HTML] (0) [PDF 914.54 K] (4488)
    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.
    2011,30(4):488-493, DOI: 1000-2421(2011)04-0488-06
    [Abstract] (1504) [HTML] (0) [PDF 1.81 M] (4483)
    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%.
    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.
    2010,29(3):363-368, DOI: 1000-2421(2010)03-0363-06
    [Abstract] (2712) [HTML] (0) [PDF 11.41 M] (4413)
    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.
    2010,29(6):798-804, DOI: 1000-2421(2010)06-0798-07
    [Abstract] (1286) [HTML] (0) [PDF 996.73 K] (4212)
    Abstract:
    The cracking of fruit skin and the splitting of underlying flesh is a kind of fruit physiological disorder,which downgrades the fruit appearance quality and causes the infection of disease,thereby reducing the commercial value and resulting in serious economic loss.Herein recent studies on fruit cracking were reviewed,mainly focusing on the influence of phenotypic characteristics,genetic factor,physiological characters,mineral nutrients,environmental conditions,plant growth regulators and cultivation practices.The prospect of research was discussed.

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