Abstract:A novel glyphosatetolerant EPSPS gene AroAI.va* derived from Isoptericola variabilisn and driven by maizederived composite ciselement was efficiently and simultaneously expressed in the plastids of leaves and nongreen tissues of tobacco. The results of transcription and proteinlevel determination of the homoplastomic transplastomic lines showed that the AroAI.va* gene was effectively expressed in the leaf and root tissues. The T0 seeds of homoplastomic transplastomic plants pLSZ3#2 and pLSZ3#3 tolerated more than 12 mmol/L glyphosate treatment. The transgenic plants cultivated in the greenhouse tolerated the spraying treatment with glyphosate at a dose of 1 800 mg/L. Reciprocal crosses between wildtype and transgenic plants confirmed that the glyphosateresistant transgenic plants obtained by plastid transformation had the characteristics of maternal inheritance.

Abstract:The “Early indica and late japonica” pattern is an important cropping pattern for double cropping rice in the middle reaches of the Yangtze River,and is of great significance to improve the efficient operation of annual nitrogen fertilizer for reducing the use of nitrogen and the loss of nitrogen to the environment. The early indica rice “Liangyou 287” and late japonica rice “Egeng 403” were used to investigate the dynamic changes of tillers,leaf area index (LAI) and SPAD values,dry matter accumulation in key periods,yield and yield components,and nitrogen use efficiency (NUE) in two seasons. Six nitrogen (basal fertilizer:tillering fertilizer:panicle fertilizer) fertilizer combinations including 3 groups of early rice:N1/N2(6∶4∶0),N3/N4(6∶3∶1),N5/N6(5∶3∶2)),2 groups of late rice:N1/N3/N5 (5∶3∶2),N2/N4/N6(5∶2∶3),and treatment of no nitrogen fertilizer (N0,CK) were set. Results showed that late nitrogen application in early rice significantly increased the rate of panicle bearing tiller,and that of N5/N6 treatment reached 95.5%. N3 treatment of late rice had the highest effective panicle. The leaf area index of early rice under N3/N4 treatment was the highest,42.6% higher than that under N1/N2 treatment. The leaf senescence rate under N3/N4 treatment was lower than that under N1/N2 treatment. The LAI of late rice under N3 treatment was the highest. The yield of N3/N4 and N5/N6 in early rice was significantly higher than that of N1/N2,with the increase of 17.3% and 14.6%,respectively. The yield of N3 in late rice was significantly higher than that of other treatments,and the annual yield of N3 treatment was the highest. The annual agronomic nitrogen use efficiency (AE) of N3 treatment was 43.3% higher than the average of other treatments. The partial production efficiency (PFP) of nitrogen fertilizer of N3 treatment was 11.7% higher than that of other treatments. It is indicated that the ratio of nitrogen fertilizer application for early indica rice was basal fertilizer∶tiller fertilizer∶panicle fertilizer=6∶4∶0,and the combination of 5∶3∶2 for late japonica rice significantly promoted the increase of annual yield and nitrogen utilization efficiency.

Abstract:A model simulation of the growth period,dry matter distribution and yield of rice was conducted based on the data from multiple field experiments and meteorological data in Hubei Province to promote the development of the “Shifting from indica rice to japonica rice” planting model in Hubei Province,increase the utilization efficiency of light and temperature resources in the rice farming model,and improve the quality of rice. Results showed that the simulation error of the growth period of indica and japonica rice in Hubei Province was within 2 days of physiological development. The simulation of growth period and panicle dry matter distribution was basically distributed near the 1∶1 line,and the fitting effect was good. The relative root mean square error (RRMSE) of the practical rice yield and the simulated yield was 11.4%,indicating that the simulation process is credible. At the same time,the simulation method of this model was used to preliminarily predict the suitable sowing date of japonica rice in Hubei Province. It will provide references for selecting the planting distribution and sowing date of  indica and japonica rice in Hubei Province.

Abstract:The phenotype plasticity of husk plays essential roles in disease resistance,insect infection and the rate of grain dehydration during the introduction of maize inbred lines from different environments. In this article,the husk traits of 50 inbred lines from 5 heterosis groups (referred to as heterotic group) in 3 environments including Sanya City,Hainan Province in 2014,Beijing City in 2015 and Tieling City,Liaoning Province in 2017 were measured. The coefficient of variation of husk traits was calculated. The variations of phenotypic plasticity of husk length (PHL),phenotypic plasticity of husk width (PHW) and phenotypic plasticity of husk layer number (PHN) among heterotic groups and the correlation within heterotic groups were analyzed. The changes of meteorological factors in different environments and growth periods were compared. The results showed that the traits of husks were significantly affected by environment. Among all lines,Lüda Red Cob and TangSPT groups,PHL and PHW were significantly positively correlated. While in Reid group,PHL and PHN were extremely significantly negative correlated. The phenotypic plasticity of husk among different maize germplasms had significant variations. PHL and PHW had the characteristics of coordinated regulation. The husk length in Lüda Red Cob group,husk length and width in PB group were insensitive to environments. These two traits remained stable during introduction to other environments. The PHL in Lancaster group was higher than that in other groups,meeting the requirements of the long husk in the South and the short husk in the North. This kind of breeding material is suitable for introduction in different places in the north and south. The average temperature and humidity in the meteorological factors were quite different at the early growth stage of maize. There was a big difference in the sunshine time at the early,middle and late growth stages of maize. It is indicated that sowing early in high temperature area and late sowing in low temperature area is beneficial to reduce the difference of husk traits among environments.

Abstract:In order to determine the colonization ability of Bacillus subtilis L1-21 in Citrus leaves and fruits and its control effect on fruit green mold,the colonization dynamics and downwardconduction of B. subtilis in citrus leaves were investigated by foliar spraying with 106 cfu/mL green fluorescent labelled strain (L1-21GFP),colonization in citrus fruits was checked through spraying and soaking with 108 cfu/mL L1-21GFP,and control effect on green mold was evaluated by spore injection with Penicillium digitatum and incidence investigation. After treatment for 10 min,the colonization of B. subtilis L1-21GFP in leaf surface and mesophyll reached 1.36×103 and 8.08×102 cfu/cm2,respectively,and displayed a continuous increasing trend. At 1 h after treatment,the GFPtagged endophyte was stable in leaf surface with 1.51×102 cfu/cm2. The bacterial concentration reached 5.67 cfu/cm2 in mesophyll at 2 h after treatment,which gradually increased to 1.15×103 cfu/cm2 after 30 h. Endophyte L1-21GFP could easily colonize in fruits,and bacterial concentration in pulp and peel after 1 h was 9.51×103 cfu/g and 3.51×104 cfu/g,respectively. However,there was significant difference in the colonization ability in fruits among different citrus varieties,and Citrus reticulata cv Ponkan had the highest colonization. In addition,after soaking for 30 min,the control effect of L1-21 on fruit green mood was 100% on the third day,and 80.36% on the fifth day. Taken together,B. subtilis L121 could colonize in citrus leaves and fruits effectively,providing a theoretical basis for further application of this strain to control citrus diseases.

Abstract:To further clarify the role of bacteria in pine wilt disease (PWD),Pinus massoniana was inoculated with Bursaphelenchus xylophilus (CK),and a mixture of B. xylophilus and the endophytic bacterium GD2 (T),respectively. Transcriptome sequencing,Gene Ontology (GO) and KEGG enrichment analysis were performed on the B. xylophilus,and realtime quantitative PCR (RTqPCR) was used to verify the accuracy of the sequencing results. The results showed that 143 differentially expressed genes (DEGs) were detected,among which 63 were upregulated and 80 were downregulated. GO analysis showed that the DEGs were enriched in immune system process,cell membrane,metabolic process,transporter activity and other functions. KEGG pathway was enriched in ECMreceptor interaction,reninangiotensin system,insulin signaling pathway and other pathways. These GO functions and KEGG pathways were involved in immune regulation and reproductive development of the body. Eight genes were randomly selected for RTqPCR verification,and the expression level was consistent with the sequencing results,which proved the accuracy of the sequencing results. The results showed that strain GD2 could affect the occurrence of PWD by improving the immune regulation ability of pine wood nematode.

Abstract:Fall armyworm,Spodoptera frugiperda,is one of the most important pests on maize,which invaded into China newly. In order to determine the control effect of Autographa californica multiple nucleopolyhedrovirus (AcMNPV) on larvae of S. frugiperda,the insecticidal activity and biocontrol effect of AcMNPV on S. frugiperda were studied and analyzed by the methods of bioassay and field efficacy test. The results showed that the median lethal concentration ( LC50 ) of AcMNPV acting on the 2nd instar larvae of S. frugiperda was 2.9×107 PIB/mL. The average control efficacy of 107 PIB/mL AcMNPV + Bt Suspension（1 500 mL/hm2）on S. frugiperda was 68.99% on the 10th day and 66.87% on the 15 th day after administration. Finally,DNAMAN 6.0 software was used to identify the DNA homology of the dead insects,and the results showed that the polh,lef8 and lef9 gene sequences sequences of the dead insect and the S. frugiperda were 100% identical. All the above results could further verify that AcMNPV may play a key role on controlling S. frugiperda. It is suggested that 107 PIB/mL AcMNPV + Bt Suspension (1 500 mL/hm2) should be applied at the peak of the occurrence of the young larvae of S. frugiperda,and 4：005：00 pm on sunny day to avoid the influence of high temperature and light,so that the virus preparation can play a better role and improve its control effect on S. frugiperda.

Abstract:Molybdenum (Mo) is one of the essential nutrient element for the plant growth,but excess Mo will cause physiological toxicity to plant. With the increase of mining area,many events of Mo pollution have been reported in the world. Meanwhile,many studies have found that some plants show strong tolerance to excessive Mo,but there are few studies on the Mo tolerance mechanisms. Therefore,we analyzed the changes of Mo content in subcellular components and leaf metabolites of wheat under excess Mo supply,and to further explore the physiological mechanism. The Mo content in cell wall,soluble part,organelle,protoplast/chloroplast of root subcellular components was 219,38,25 and 62 times higher than that in shoot respectively; The accumulation proportion of Mo in soluble fraction of root and shoot was 71.85% and 88.54%. Under excess Mo,the contents of malic acid and fumaric acid in wheat leaves were increased by 2.08 and 2.07 times,and the contents of βalanine,Lserine,Lthreonine and Lglutamine were increased by 2.78,1.89,1.67 and 1.91 times,respectively. These results indicate that root system can prevent and control the transportation of excess Mo to shoot,and vacuole can be the main storage site of excess Mo，and organic acids and amino acids produced may chelate with Mo in vacuole to reduce its biological toxicity. This study provided theoretical basic for the mechanism of plant tolerance to excess Mo stress,and supplied the technical support for plant remediation of soil Mo pollution.

Abstract:Field plot treatment and two groups of experiments including CK (conventional fertilization) and T (750 kg/hm2 biochar + conventional fertilization) were used to study the effects of biochar on soil nutrients and rhizosphere bacterial community structure of fluecured tobacco at maturity stage. The results showed that biochar significantly increased soil pH,the content of available phosphorus,available potassium and organic carbon,and promoted the growth and development of tobacco plants. Compared with CK,the abundance of Chloroflexi,Acidobacteria and Firmicutes increased by 1.82%,12.36% and 64.55%,respectively. The abundance of Actinobacteria and Proteobacteria decreased by 2.02%,and 9.00%,respectively. The results of cluster and principal component analyses showed that the dominant bacteria were significantly correlated with the soil pH,available potassium,available phosphorus and organic carbon. The Firmicutes,Myxococcota and Desulfobacterota were significantly positively correlated with soil pH,available phosphorus,available potassium and organic carbon (P<0.05). The Bacterdidota and Patescibacteria were negatively correlated with soil pH,available potassium,available phosphorus and organic carbon. Biochar application can improve the quality of tobacco leaves by improving the mineral nutrition and microbial community around the roots. Biochar is conducive to soil nutrient retention and growthpromoting bacterial communities in the rhizosphere during the maturity period of tobacco. It will provide a theoretical reference for regulating soil nutrition and microecological environment during tobacco maturity.

Abstract:Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) belongs to the lighttolerant coniferous species of Cunninghamia family,which is widely distributed in China and Vietnam. It has a series of characteristics including fast growth,high yield,beautiful wood grain,insect resistance (such as termites),corrosion resistance,and adaptability to arid and arid habitats. It is one of the important endemic fastgrowing timber species in China. In order to solve the decline of soil quality in Chinese fir plantations and the problem of soil fertility decline,effects of fertilization and litter addition on soil nutrient and soil microbial properties of Chinese fir plantation in Central South Jiangxi Province were studied by using the bag method to set up different fertilization treatments and litters of multiple tree species combined treatments. The results showed that compared with the control (without fertilization) treatment, the content of soil alkline nitrogen and available phosphorus of mixed N + P fertilizers treatment in the Chinese fir plantation soil increased by 10.7% and 36.7%, respectively, which was significantly higher than that of the single fertilizer treatment. Compared with the control (without addition of litters) treatment,mixed addition of litters of C. lanceolata+P. bournei and single addition of P. bournei litter promoted soil microbial biomass significantly,indicating that the litter of P. bournei played a key role in decomposing the mixed litter of Chinese fir plantation. In practice,the mixed forest of C. lanceolata × broadleaved is recommended,and the current young to mid age pure C. lanceolata stand should be reformed by means of closetonature transformation in order to change the composition,quality and quantity of litter. In this way,the additive effect of decomposing mixed litter of multiple tree species can be fully used and the soil nutrient status of the Chinese fir plantation can be improved by combining with the application of mixed N+P fertilizers.

Abstract:Groundwater is very important water source for the survival and development of oasis in arid area. The hydrochemical data of 66 groundwater samples in Yaoba Oasis of Inner Mongolia were selected to analyze the hydrochemical characteristics and genesis of groundwater with methods of classical statistics,Piper trigraph,Gibbs graph,main ion concentration graph,etc to understand the chemical characteristics and causes of groundwater,and also to provide the basis of data for water quality evaluation. Results showed that the groundwater presented weak alkalinity and brackish water. The main chemical processes were evaporation concentration and rock weathering. The main sources of groundwater chemical components were dissolution and precipitation of calcite,dolomite,rock salt and gypsum. From northeast to southwest,the chemical types of groundwater changed from SO4·ClCa·Mg and SO4·HCO3·ClMg·Na to SO4·ClCa·Na. The high salt ions were enriched. The overall salinization degree of the groundwater body is obvious. It will provide guidance for rational exploitation and protection of groundwater in this area.

Abstract:Production agglomeration is an effective way to promote the sustainable development of agricultural economy. This article studied the factors influencing production agglomeration of planting industry in China to provide a reference for policy making to optimize the layout of agricultural production and increase the effective supply of agricultural products. The spatialtemporal characteristics of production agglomeration of planting industry in China from 1998 to 2018 were described by calculating the spatial Gini coefficient,industrial concentration rate,production scale index and spatial autocorrelation index. The Durbin model with period and spatial double fixed effects was used to empirically analyze the factors affecting production agglomeration. The results showed that the degree of production agglomeration of planting industry in China first increased and then decreased slowly,and the distribution of production had a significant positive spatial correlation. The increase in the amount of agricultural arable land,the efficiency of utilizing chemical fertilizer,the density of transportation facilities,and the financial support for agriculture and the industrialization level was conducive to the increase in the degree of production agglomeration of planting. However,rural human capital did not play a positive role in promoting the agglomeration. The impact of the degree of disaster,the level of mechanization and the degree of economic openness was not significant in the model. Policy recommendations including encouraging moderatescale operations,training agricultural professional and technical personnel,and building a supporting industrial chain for agricultural products are put forward.

Abstract:The concept of bottomline thinking was introduced into the study of rural planning to provide ideas and references for innovating the theory and method of rural planning,further to ensure the implementation of the rural revitalization strategy,guide the modernization of agriculture and rural development,and scientifically formulate various plans for rural areas. The characteristics and problems of countryside and rural planning in China were analyzed. The necessity of formulating rural planning based on bottomline thinking was clarified. The concept and level of bottomline thinking was briefly described. The bottomline goal and standard of rural planning was determined. The implementation strategy of bottomline thinking in rural planning was explored with cases analysis. The results showed that the countryside was the stabilizer and reservoir of modernization in China. The poor and weak foundation and lagging development of the rural areas has not been fundamentally changed. Planning guidelines are urgently needed in terms of industrial development,space utilization,rural construction,and rural governance. Traditional rural planning is deficient in coordination,implementation and restraint,with the main manifestations including insufficient understanding of the objective laws of rural development,inaccurate grasp of basic functions,weak spatial overall planning and control,being difficult to guide and drive rural selfdevelopment and insufficient to meet the dynamic and complex development needs of rural areas. It is proposed that planning methods and strategies based on the bottomline thinking including following the laws of rural development,releasing the basic functions of the village,meeting the national strategic requirements,conforming to the agricultural and rural policy direction,guiding the village to stick to the bottom line of space,and activating the endogenous power of the village can be used to solve the problem of rural development. The results showed that applying the bottomline thinking in rural planning can help to find and solve rural problems,improve the scientific basis of rural planning,and promote the innovation of theories and methods for rural planning.

Abstract:The volatile compounds in the peel of Xinli No.7 collected from Alar,Xinjiang and Baoding,Hebei Province were detected with HSSPMEGCMS,and compared with that of P. bretschneideri Rehd ‘Zaosu’ (the male parent) and P. sinkiangensis ‘Korla’ (the female parent) collected from Alar to explore the changes of volatile profiles of hybrids. The results showed that a total of 119 volatile compounds were detected in all samples. 55,53,56 and 100 volatile compounds were detected in Xinli No. 7 from Xinjiang and Hebei and its parents. The total content of volatile compounds in the peel of Xinli No. 7 from Xinjiang and Hebei Provinces was 4.52 and 2.48 times that of the male parent,and 0.47 and 0.26 times that of the female parent. Compared with its parents,8 and 42 volatile compounds were under detection level in Xinli No.7. (E)2Octenal,1dodecene,cedrol,2heptanone,2decanone and 1,2,4,5tetramethylbenzene were newly detected in Xinli No.7. (E)2Hexenal and hexanal was the highest content ingredient shared by the four. (E)2Hexenal,hexanal together with other 5 compounds in peel of Xinli No.7 were close to the high content of its parents,while the content of 30 compounds was close to the low content of its parents. In general,the types of volatile compounds in Xinli No. 7 were less than those of the parents,but 6 new types were added. The total content in hybrid was higher than that in the male parent and lower than that in the female parent. Different origin areas had an impact on the volatile profiles of Xinli No.7. 〗

Abstract:The combined molecular markers including InDel,ESTSSR and SSR were used to analyse the genetic diversity of 94 lotus germplasms introduced in Kunming region. The results showed that a total of 204 bands were amplified by the 60 pairs of primers screened,and 233 alleles were detected. The average Shannon’s index of the three markers was more than 0.8,the index of gene diversity was above 0.52,indicating that the detection rate of diversity is high.The result of Mantel test showed that the correlation r values between the combined markers and each independent marker were all higher than 0.789 4. Ninetyfour germplasms were divided into 5 groups with cluster analysis and population structure analysis of combined markers,which was related to traditional classification and provenance classification. There were obvious differences in genetic diversity between American lotus and Asian lotus. According to genetic composition,SinoAmerican hybrid lotus is distributed in American lotus or Asian lotus. In summary,the 94 lotus resources introduced to Kunming are rich in genetic diversity,and the combined molecular markers have a high detection rate of diversity in lotus germplasm resources. It will provide germplasm resources and technical support for further selecting and breeding elite lotus varieties.

Abstract:From 2017 to 2020,the biological resources such as fish,plankton and aquatic macrophytes at Hanzhong,Laohekou and Zhongxiang sites in the main stream of Hanjiang River were investigated and analyzed seasonlly. The results showed that 98 species of fishes were collected,among which the economic fish were mainly carp,crucian carp,silver carp,bighead carp,and grass carp,etc. A total of 116 species of phytoplankton belonging to 71 genera,7 phyla were identified,among which 46 species were Chlorophyta,and 12 dominant species were Bacillariophyta. A total of 86 species of zooplankton belonging to 55 genera were detected,among which 48 species were rotifers,and 8 species were dominant,mainly protozoa. There are 29 species of aquatic macrophytes belonging to 24 genera and 16 families. Compared with the monitoring data in the past,there are 38 fewer fish species in the main stream of Hanjiang River,and the main species were rare and small fish,such as Metahomaloptera omeiensis and Glyptothorax sinensis. There were 27 new fish pecies,the total number of fish species decreased,the catch miniaturization was obvious,and the fishery resources declined. The species,density and biomass of phytoplankton increased; the species of zooplankton increased,and the density and biomass increased; and the species of aquatic macrophytes decreased. The above changes are related to the construction of water conservancy projects such as the Middle Route Project of South to North Water Diversion and the cascade development of Hanjiang River,the change of hydrological regime such as the decrease of discharge water,the artificial regulation of runoff,the decrease of discharge water temperature,the slowing down of water flow in some river sections,and the acceleration of water eutrophication. It is suggested that the protection of fishery resources and environment in Hanjiang River should be strengthened through the implementation of pollution control in the river basin,the implementation of artificial proliferation and release,and the management and control of ecological flow.+E100

Abstract:In order to further explore the interaction of elongase 5 (elovl5), elongase 2 (elovl2) and desaturase 2 (fads2) in the synthesis of highly unsaturated fatty acids (HUFA) in freshwater fish, we successfully constructed four zebrafish mutations including elovl5-/- (E5-/-), elovl2-/-*elovl5-/- (E2-/-*E5-/-), elovl5-/-*fads2-/- (E5-/-*F2-/-) and elovl2-/-*elovl5-/-*fads2-/- (E2-/-*E5-/-*F2-/-) using CRISPR/Cas9 technology, and soybean oil (SO) and canola oil (CO) feeding experiments were carried out on four mutants. The responses of zebrafish elovl5, elovl2 and fads2 to different fat sources in the feed during the HUFA synthesis process were studied. The results showed that in the E5-/- and E2-/-*E5-/- group, the extension of C18PUFA to C20PUFA still existed, while C18:3n-3 (ALA) and C18:2n-6 (LNA) showed significant accumulation in the E5-/-*F2-/- and E2-/-*E5-/-*F2-/- group. The expression of elovl4a and elovl4b in the liver were induced after mutation of elovl2, elovl5 and fads2. The results of fatty acid analysis showed that the DHA content of E5-/- group was not significantly different from that of WT, and the DHA content of E5-/-*F2-/- group was significantly lower than that of WT after fed with SO feed. However, the DHA content of E5-/- group was significantly higher than that of WT, and there was no significant difference between E5-/-*F2-/- and WT after CO feed was fed. Zebrafish desaturation was significantly affected without fads2, indicating that fads2 is an essential enzyme in the process of HUFA synthesis. The missing phenotype of elovl2 and elovl5 may be compensated by other HUFA synthesis pathways. This experiment further verified that elovl2 and elovl5 had gene interactions in HUFA synthesis, and fads2 was essential in HUFA synthesis as a desaturase. This study provides a theoretical basis for improving the HUFA synthesis ability of freshwater fish.

Abstract:To determine the optimal temperature of embryonic and larval development of Procambarus clarkii,we observed the embryonic and larval development process,and recorded the survival rate,development time,biological zero degree and effective accumulated temperature at four temperatures (19℃,22℃,25℃ and 28℃). The results showed that the hatching time,hatching rate and larval development of P. clarkii were significantly affected by temperature (P<0.05). The embryonic development was accelerated with the temperature increasing within the experimental temperature range (1928℃),and the development time at 19℃ was (622.67±6.02) h post spawning,while it was only (349.67±4.63) h at 28 ℃. The embryonic hatching rate firstly increased and then decreased with the temperature increasing,with the highest hatching rate of 91.03%±2.97% and lowest of 40.53%±4.97% obtained at 22 ℃ and 28 ℃,respectively. The larval development time decreased with the increase of temperature,and the development time at 19 ℃ was (304.00±10.73) h,while it was only (194.00±9.03) h at 28 ℃. The larval survival rate firstly increased and then decreased with the increase of temperature,and the highest (94.37%±1.60%) and lowest (82.67%±1.51%) survival rate were obtained at 22 ℃ and 28 ℃,respectively. The biological zero of embryonic and larval development calculated by SandersonPearis formula were 7.32 ℃ and 3.29 ℃.Further,a temperaturedependent developmental model for the P. clarkii embryos and larvae was built. According to the curve fitting equation,the optimal temperature of embryonic and larval development were 22.06℃ and 22.78℃,respectively. Therefore,it is recommended that the optimal temperature range for the embryonic and larval development during artificial P. clarkii breeding process should be set at 2225℃.

Abstract:In the breeding of Bellamya,weight data of some individuals are often missing．To make best use of information on all individuals with excellent breeding performance，an artificial neural network was trained on four morphological traits (including shell height，shell width，aperture height and aperture width) and body weight data of 784 individuals from five geographical populations including Yangcheng Lake，Jiangyin，Guanlian Lake，Hong Lake and Xiantao．After this，data of 261 individuals from Tai Lake were used to test the artificial neural network model．In the end，an artificial neural network model for predicting missing body weights of Bellamya was successfully established．In addition，the artificial neural network model was used to predict the missing body weights of 201 Bellamya from Weishan Lake，and the determination coefficient of this method was compared with those of two other prediction methods (i.e.，the predicted mean matching method and the random forest prediction method)．The results showed that the determination coefficient of the artificial neural network model constructed in this study was 0.96 for predicting the missing body weight，which was obviously higher than those of the predictive mean matching method (0.87) and the random forest prediction method (0.85)．This study could provide an efficient method for the prediction of missing values of body weight involved in the breeding process of the Bellamya．

Abstract:Short chain fatty acids (SCFAs) are important metabolites of gut microbiota,and are currently important media and approaches for studying gut microbiota,diagnosing and treating intestinal diseases and metabolic diseases. Feces are closely related to the intestine,and the types and abundance of fecal SCFAs can sensitively reflect the changes in the intestinal microenvironment and gut microbiota. It is currently one of the most widely studied biological samples for SCFAs. However,SCFAs are highly polar,volatile,low in content and complex biological matrix,which makes the accurate quantification of SCFAs have great troubles and challenges. Therefore,the establishment of a detection method with simple operation,high sensitivity and low cost of analysis is of great significance for analyzing SCFAs in feces. In order to be more suitable for the trace detection of SCFAs in biological samples,propyl chloroformate was used as the derivatization reagent,combined with head spacesolid phase microextraction (HSSPME) technology for the analysis of SCFAs in rat feces. The conditions were optimized. The derivatization conditions were pH8.0,300 μL propanol,100 μL pyridine,100 μL propyl chloroformate and vortex derivatization for 2 min. The conditions of HSSPME were pH 3.46,extraction temperature 50℃,extraction time 40 min and stirring speed 1 000 r/min. Under optimized conditions,a derivatization HSSPMEGC method for analyzing free SCFAs in rat feces was established. The LOD and LOQ of the method established were between 0.1330.420 μmol/kg and 0.4441.400 μmol/kg,far lower than the LOD and LOQ of the method in the literature. The linear relationship was good (R2>0.99). The accuracy was high,the recovery rate of standard addition was between 65.42% and 117.69%,and the RSD was lower than 11.60%. The method is simple,fast,sensitive and low in cost,and can fully meet the needs for trace detection of shortchain fatty acids in feces. It will provide new technical support and reference for trace analysis of SCFAs in complex biological samples including blood and tissue as well.

Abstract:In order to study the effect of buckwheat honey on improving the liver injury induced by alcohol and the dysbiosis of gut microbiota in mice,the liver index,activity of serum transaminase was measured after buckwheat honey administration in the mice with liver injury induced by alcohol. The effects of the liver index,activity of serum transaminase on the liver lipid metabolism,oxidative stress and liver tissue were analyzed. The changes of gut microbiota in mice were analyzed with highthroughput sequencing. The results showed that compared with the alcohol model group,buckwheat honey significantly reduced the levels of alanine aminotransferase (ALT),aspartate aminotransferase (AST),malondialdehyde (MDA),and the liver fat droplet phenomenon caused by alcohol (P<0.05),reduced the level of liver triglyceride (TG),improved the activity of superoxide dismutase (SOD),and significantly improved the steatosis. Compared with the alcohol model group,the intake of buckwheat honey improved the diversity and richness of gut microbiota in mice caused by alcohol intake. At the phylum level,the abundance of Bacteroidetes increased by 7.18%,the abundance of Firmicutes decreased by 15.59% and the ratio of Firmicutes to Bacteroidetes decreased by 21.25% and restored to the level of blank control group. The results of further analyzing the top 36 abundant microorganisms at the genus level showed that buckwheat honey significantly improved the changes of 16 bacterial genera caused by alcohol. It is indicated that buckwheat honey can improve the liver injury and gut microbiota imbalance caused by alcohol in mice,and can be developed and utilized as a raw material for liver protection products.

Abstract:Alkaline extraction was used to extract waterunextractable arabinoxylan (WUAX) and waterextractable arabinoxylan (WEAX) from wheat bran. The bile salt binding capacity and pancreatic lipase inhibitory activity of WUAX and WEAX were investigated to reveal the effects of wheat bran arabinoxylan (AX) with different types of structure on lipid reduction in vitro. The results showed that the binding rate of WEAX to bile salt was less than 15%,and the binding capacity of WUAX to bile salt was stronger than that of WEAX. The binding rate of WUAX to sodium taurocholate hydrate and sodium glycocholate hydrate was 52.87% and 38.30%,respectively. The Freundlich equation was used to fit the isothermal adsorption curves,and the 1/n of WUAX to sodium taurocholate hydrate and sodium glycocholate hydrate was 0.51 and 1.30,respectively,indicating that compared with sodium glycocholate,WUAX bound to sodium taurocholate more tightly. Contrary to the binding capacity of bile salt,WEAX had a significantly higher inhibition rate on pancreatic lipase than WUAX. The inhibition rate of WEAX on pancreatic lipase increased with the increase of the concentration,with the highest inhibitory rate of 35.93% when the concentration was 30 mg/mL. The results of the reaction rate curve and the LineweaverBurk curve showed that the inhibition of pancreatic lipase by WEAX was reversible,and the type of inhibition was mixed inhibition. In summary,there are difference in the effect of WUAX and WEAX on lipid reduction in vitro,which is related to the difference in the characteristics of structure. It will provide practical reference and theoretical support for further studying the mechanism of lipid metabolism regulated by AX.

Abstract:A complete set of path optimization algorithm solution for cooperative operation of multiple UAVs is proposed to figure out the path planning problem of multiple agricultural UAVs under the condition of multiple fields with obstacles. Taking the minimum transfer path length as the goal of operation optimization,the initial coverage operation route with horizontal heading conditions was calculated based on the polygon scanning and filling algorithm,and the safety boundary intersection test of the dangerous transfer process between routes was carried out. The course of operations of each single field was optimized with “minimum span method” of convex polygon and “step rotation method”of nonconvex polygon. The mathematical models for route scheduling and voyage planning were established,and the solution was obtained based on the open source optimization software suite of Google ORTools. The operation effects of different route combination scheduling strategies and the effects of operation optimization of the five optimized searching strategy algorithms of Google ORTools and the equal area partition algorithm of UAV along the heading direction were compared. The simulation results of four sets of hypothetical and real fields showed that the algorithm effectively achieved multiple cooperative UAVs path planning under various constraints and took 70552 s. Compared with the equal area partition algorithm,the optimal results for the total length of the transfer path decreased 24.86%47.10%.

Abstract:A critical negative pressure model of seed suction process of metering device was established with the principle of combined seeding with negative pressure suction and positive pressure injection to figure out the practical problems of sesame production including low efficiency of artificial planting,timeconsuming and high labor intensity of thinning and setting seedlings after emergence,and lack of suitable precision hole metering device. The different posture of seed suction and the contacting area between seed and pore was analyzed. The critical negative pressure of 14 seeds adsorbed by the hole was obtained with the multiobjective optimization method. The optimal hole diameter range of sesame precision hole sowing was determined to be 0.81.1 mm. The results of the image shooting test of the seed suction and transporting state showed that the different adsorption posture and probabilities of sesame was horizontal lying∶side lying∶upright ≈ 3.5∶ 1∶ 1. The variation of negative pressure required by different number of seed suction was consistent with the critical negative pressure model. The optimization test based on response surface was carried out to analyze the effects of the diameter of metering disc hole,rotation speed of seed metering device and negative pressure of air chamber on the seed metering performance including the rate of qualified number of seed in the hole,the rate of missed seeding and the rate of multiple seeding. The results showed that the rate of the qualified number of seeds in the hole,the rate of missing seeding,and the rate of multiple seeding was 96.04%,0.21%,and 3.75% when the diameter of metering disc hole,the negative pressure and vacuum degree of the air chamber,and the rotation speed of the metering shaft was 1.0 mm,-800 Pa,and 8.66 r/min,meeting the agronomic requirements of sesame planting. It will provide a reference for improving the structure of sesame precision hole seeding metering device.

Abstract:At present,the mechanized harvest of lotus roots is low,the labor intensity of workers is high,and the harvesting efficiency of lotus roots is low. Therefore,a walking hydraulic scour type lotus root digging machine was designed. Hydraulic system was used to control the reciprocating movement of sewage submersible pump and nozzle. Two sewage submersible pumps were used to control one nozzle respectively to make the water flow have enough flow and pressure. The hydraulic control system was simulated and analyzed by AMESim,it was found that the hydraulic system works well through the adjustment test of the hydraulic system. In addition,a BoxBehnken test was carried out,and the response surface analysis and parameter optimization analysis were carried out,where the jet angle of the nozzle,the depth of the nozzle into the mud and the moving speed of the hydraulic cylinder for pushing were taken as the test factors,while the scour depth and the floating rate as test indexes for design. The experimental results show that when the jet angle of the nozzle is 30°,the depth of the nozzle into the mud is -24 mm,and the moving speed of the hydraulic cylinder for pushing is 10 cm/s,the scouring performance of the machine reaches the optimal state，at this moment the scour depth is 302 mm,and the floating rate is 90%.The research can provide reference for the design and optimization of the lotus root digging machine.

Abstract:The Geomagic studio 3D and SolidWorks software were used to 3D modeling the main lotus root of Elian No.5 with the elastic modulus,shear modulus,Poisson’s ratio and other intrinsic parameters obtained by uniaxial compression test and the contact parameters including the collision coefficient of restitution,static friction coefficient and rolling friction coefficient among lotus roots and between lotus roots and steel obtained by friction and collision test.The Hertz Mindlin with bonding model in EDEM simulation software was used to establish the discrete element model of main lotus root.The bending failure test of the main lotus root was conducted on the texture analyzer.Referring to the test results,the singlefactor and twofactor discrete element simulation tests of the bending failure of the main lotus root were carried out with normal stiffness per unit area,shear stiffness per unit area,critical normal stress and critical shear stress as the influencing factors.The results showed that the normal stiffness per unit area and the shear stiffness per unit area significantly affected the displacement and the first peak value when the first bending failure occurred,while the critical normal stress and the critical shear stress had no obvious effects on them.When the critical normal stress was 3.80 MPa and the critical shear stress was 3.12 MPa,the optimal solutions of the normal stiffness per unit area and the shear stiffness per unit area were obtained by steepest descent method to be 5.814×108 N/m3 and 3.450×108 N/m3,respectively.Based on this,the simulation peak value of the first bending failure of the main lotus root was 269.72 N and the displacement value was 7.14 mm.The relative errors of the simulation results and the measured results were 2.56% and 2.00%,respectively.The discrete element model of lotus root established will provide important reference for simulating the mechanical harvesting process of lotus root and effectively reducing the damage of lotus root.

Abstract:The traditional sensory evaluation and wet chemical detection of tea quality have limitations including strong subjectivity,timeconsuming and laborious determination. As a new type of analytical technique,near infrared spectroscopy has the advantages of fast,nondestructive,and objective results,and has been widely used in tea. Based on introducing the principle of nearinfrared spectroscopy technology,this article mainly reviewed the use of near infrared spectroscopy in analyzing the quality of tea fresh leaves,detecting component,identifying tea grade and tea species,tracing tea geography and analyzing tea products deeply processed. The problems in using nearinfrared spectroscopy technology in tea are analyzed. Some targeted countermeasures were proposed. It is expected that near infrared spectroscopy technology can provide solid scientific and technological support for the development of tea industry.

Abstract:The quality of flavor has gradually become an important reference indicator of whether food can be favored by consumers. Carbohydrates as one of the main nutrients in food have been found to have a significant impact on the retention and release of volatile flavor compounds in food. This article reviews the mode of action of carbohydrates and volatile flavor compounds,and elaborated the effects of carbohydrates and the volatile flavor compounds on the release and retention of volatile flavor compounds in carbohydrate matrix. It will provide a scientific basis and reference for the controlled release of volatile flavor compounds in carbohydrate matrix.

Abstract:With the continuous expansion of mariculture in China,the pollution of shrimp culture has become one of the important pollution sources in the coastal waters of China.In recent years,the promulgation of relevant documents such as Several Opinions on Accelerating the Green Development of Aquaculture Industry have put forward new requirements for accelerating the green development of aquaculture industry.It is of great environmental and ecological significance to summarize the current status and put forward integrated technology suitable for shrimp tail water treatment in China.This paper outlines the development status of the Chinese shrimp mariculture industry,the characteristics of mariculture wastewater and the impact of mariculture wastewater on Chinese offshore waters,details the plant,animal and microbial treatment technologies and resource utilization technologies for shrimp mariculture wastewater with cases and literature,and analyzes the advantages,disadvantages and application potential of each integrated technology.Based on the application status of tail water treatment technologies in mariculture demonstration areas in China,the future discharge management and resource utilization of shrimp mariculture wastewater are prospected.