Abstract:In order to screen the endophytes of Paeonia lactiflora Pall with good antibacterial activity against gram-negative bacteria,the endophytes of P.lactiflora which have antagonistic effect on Escherichia coli and Salmonella were isolated by surface disinfection and plate face-off method,and its antibacterial effect and secondary metabolites were studied.The species was identified by morphological observation and 16S rRNA gene sequencing.20 strains of endophytic bacteria were isolated from different tissues such as root,stem and leaf.A gram-negative endophyte HNYJ291 with good antibacterial effect was obtained from 20 endophyte strains by plate confrontation assay,which was identified as Paenibacillus kribbensis by morphological observation and molecular analysis.The bacteria could effectively inhibit E.coli and Salmonella.Whole genome sequencing analysis showed that the genome size of strain HNYJ291 was 5 609 136 bp,the GC content was 45.48%,and the number of coding genes was predicted to be 4 805.4 779,3 678,4 027,3 941,2 994 and 2 700 genes were annotated by NR,Swiss-Prot,Pfam,COG,GO and KEGG databases,respectively,and 10 gene clusters related to secondary metabolite synthesis were predicted by antiSMASH.The main secondary metabolites included cyclolipopeptides antibiotics(fusaricidin B),bactericin(paenilan),antimicrobial lipids(tridecaptin),polymyxin and antimicrobial peptides(paenicidin A),etc.From gene clusters related to antibacterial active substances in its genome,it can be predicted that this strain has the potential to develop new drugs and be used as a feedable microorganism.

Abstract:In order to further study the molecular mechanism of γ-gliadin 1 gene in regulating flour quality of wheat,the γ-gliadin 1 gene was cloned using Zhengmai 158(low protein content and high dough strength)as materials,bait vector pGBKT7-γ-gliadin 1 was constructed,the interacting proteins of wheat γ-gliadin 1 were screened from Zhengmai 158 cDNA library by the yeast two-hybrid system,and rotary test was used to validate the interaction between key candidate proteins and γ-gliadin 1.The results showed that the γ-gliadin 1 gene was successfully cloned with the cDNA length of 1 020 bp.A total of 117 blue clones were screened by the yeast two-hybrid system.Ten possible candidate interacting proteins of γ-gliadin 1 were obtained through colony PCR detection,sequencing,and homology analysis using the BLAST on NCBI,which were cysteine-rich and transmembrane domain-containing protein 1-like(XM_044546254.1),alpha-amylase/trypsin inhibitor-like(XM_044509330.1),lichenase 2(XM_044550285.1,XM_044594213.1),sucrose 1-fructosyltransferase-like(XM_044554537.1),pullulanase 1(XM_044577151.1),ervatamin-B-like(XM_044577994.1),cell number regulator CNR8-like(XM_044483337.1,XM_044491902.1)and CNR2-like(XM_044468782.1)related to plant reproductive growth(especially development of fruit or grain),and ubiquitin domain-containing protein DSK2b-like(dominant suppressor of KAR 2b like,XM_044546840.1)and CIP73(CCa MK-interacting protein of 73 ku,XM_0445 54473.1),respectively.The rotation validation assays of candidate interacting proteins indicated that four candidate proteins were probably interacted with γ-gliadin 1,which were cysteine-rich and transmembrane domain-containing protein 1-like,alpha-amylase/trypsin inhibitor-like,lichenase 2 and ervatamin-B-like,respectively.Therefore,it is speculated that γ-gliadin 1 may mainly interact with these candidate proteins to be involved in the synthesis and degradation of storage proteins(such as cysteine)and starch in wheat grains.

Abstract:To investigate the genes associated with the growth-promoting effects of Bacillus subtilis in Rehmannia glutinosa,whole genome sequencing was performed in this study and the genes associated with the growth-promoting effects were discovered through functional annotation.The results showed that the genome size of Bacillus subtilis,an endophytic growth-promoting bacterium of Rehmannia glutinosa,was 4 310 699 bp,with a GC content of 43.44%,and a total of 4 521 predicted coding genes.A total of 3 013,3 354,4 395,206,52,and 212 functional genes were annotated in the clusters of orthologous groups(COG),gene ontology(GO),kyoto encyclopedia of genes and genomes(KEGG),carbohydrate-active enzymes(CAZyme),comprehensive antibiotic resistance database(CARD),and virulence factor database(VFDB),respectively.The annotation results indicated that there were 46 genes related to growth-promoting function,with the majority of these genes involved in phosphorus solubilization,nitrogen fixation,and iron carrier processes.In the meantime,anti-SMASH predicted that a total of 409 genes were enriched into 12 secondary metabolite synthesis gene clusters,with the majority encoding eight repressors,including fengycin,1-carbapen-2-em-3-carboxylic acid,bacillaene,bacilysin,subtilosin A,surfactin,pulcherriminic acid,and bacillibactin.Among these,pulcherriminic acid and bacillibactin had been observed to facilitate the chelation of ferric ions in the surrounding environment.

Abstract:The high Zn efficiency variety Zhengdan 958(ZD958)and Zn no-sensitive variety Longping 638(LP638)were used as materials.The field plot experiment was conducted with three N rates[225 kg/ha(HN),180 kg/ha(MN)and 90 kg/ha(LN)]and two foliar Zn treatments[no Zn(F0),spraying Zn of 1∶1 at jointing stage and flare opening stage(F1)],and the effects of N and Zn application on the filling characteristics of grains at different positions and their relationship with grain yield of different Zn efficiency varieties were studied,so as to provide reference for N and Zn application in the maize production.The results showed that HN treatment had the highest yield,followed by MN treatment,and there was no significant difference between HN treatment and MN treatment.HN treatment increased grain weight at different positions.MN treatment delayed the time with the maximum grain-filling rate(TGmax)at different positions,and increased the maximum grain-filling rate(Gmax)at upper position and active grain-filling period(D)at basal position of ZD958 ear,while HN treatment delayed TGmax,prolonged D of different positions,and enhanced the grain weight with the maximum grain-filling rate(WGmax)at upper and basal positions of LP638 ear,thus increasing grain yield.Compared with F0 treatment,F1 treatment significantly decreased the bare tip length by 9.9%,significantly increased the yield by 2.0%,increased the grain weight,extended D and postponed TGmax at upper and basal positions of ZD958 ear,and increased WGmax.The grain yield was significantly positively correlated with TGmax at basal position of ear,and the grain weight at middle position of ear was extremely significantly positively correlated with the grain weight at basal position of ear.To sum up,applying 180 kg/ha N and spraying 4.5 kg/ha Zn of 1∶1 at jointing stage and flare opening stage can delay TGmax at upper and basal positions of ear,extend D,and increase WGmax and grain weight of high Zn efficiency maize genotype,thus promoting the increase of yield.

Abstract:Four treatments were set up,which were rice-turtle-Trionyx-fish comprehensive planting and breeding(DGBY),rice-turtle-fish comprehensive planting and breeding(DGY),rice monoculture(DCK)and rice ecological blank planting(DCK0).The effects of different comprehensive planting and breeding modes on the control of diseases,pests and weeds in paddy fields and rice yield and quality were studied,so as to promote the quality and efficiency of rice-fish comprehensive planting and breeding productivity.The results showed that compared with DCK0 treatment,DGBY and DGY treatments had control effects on rice sheath blight,rice blast and rice false smut.Among them,the control effect on rice sheath blight was the best,but the control effect was significantly lower than that of DCK treatment,which was 15.36%and 13.19%,respectively.The control effects of DGBY and DGY treatments on the 5th generation of rice planthopper were better,and the number of insects decreased by 56.79%and 48.85%compared with DCK0 treatment,and decreased by 32.29%and 16.95%compared with DCK treatment,respectively;Followed by the 3rd generation of Chilo suppressalis,the number of insects decreased by 39.29%and 33.93%compared with DCK0 treatment,and decreased by 15.00%and 7.50%compared with DCK treatment,respectively.At fifty days after the animals were stocked,the control effects of DGBY treatment on weed density and dry weight were 38.38%and 40.15%,respectively,and those of DGY treatment were 32.99%and 35.39%,respectively,which were not significantly different from those of DCK treatment.Except that the actual rice yield of DCK treatment was significantly higher than that of DCK0 treatment,there was no significant difference among other treatments.The milled rice rate of DGBY and DGY treatments were extremely significantly higher than that of DCK0 treatment,and the chalky grain rate and chalkiness were lower than those of DCK treatment,so DGBY and DGY treatments had the effect of improving rice quality.In summary,the rice-turtle-Trionyx-fish and rice-turtle-fish comprehensive planting and breeding models can reduce the harm of diseases,insects pests and weeds to a certain extent,achieve stable yield and improved quality,and reduce the use of chemical fertilizers and pesticides.

Abstract:Using the new wheat line of China Agricultural University,Nongda 136,as the experimental object,a pot planting method was used to study the effects of adding 5%,10%,15%biochar and various concentrations of biochar+plant growth promoting bacteria(PGPB)to soil under mine wastewater irrigation on wheat yield and soil environment.The results showed that compared with ordinary well water irrigation,soil enzyme activity was weakened and microbial carbon and nitrogen content was reduced under mine wastewater irrigation;The vitality of wheat root system decreased,with the highest performance at the jointing stage,followed by the flowering stage,and the lowest at the heading stage;The plant height,single stem dry matter weight,actual yield and biomass yield of wheat at different growth stages showed a decreasing trend.However,adding various concentrations of biomass charcoal and PGPB treatment was beneficial for improving soil environment,promoting wheat growth and yield increase.Compared with the control treatment,the soil catalase,sucrase,polyphenol oxidase,acid phosphatase,and dehydrogenase activities increased by 90.6%,37.5%,60.3%,55.7%,and 69.2%respectively when treated with 10%biomass charcoal+PGPB under mine wastewater irrigation;The soil pH value,total nitrogen,and available potassium content increased by 11.1%,185.4%and 63.9%,respectively;The soil microbial biomass nitrogen content reached 139.1 mg/kg and microbial biomass carbon content reached 253.4 mg/kg during the wheat heading stage treated with 10%biomass charcoal+PGPB;The biological yield and actual yield of mature wheat increased by 24.4%and 24.0%,respectively.In summary,the addition of different concentrations of biomass charcoal and PGPB treatment can improve soil enzyme activity,microbial carbon and nitrogen content under mine wastewater irrigation,significantly improve soil physicochemical properties,increase relative chlorophyll content,net photosynthetic rate and root vitality of wheat at different growth stages,increase plant height,single stem dry weight and yield at maturity.Among them,the best yield increase effect is achieved under the treatment of 10%biomass charcoal+PGPB.

Abstract:The application of phosphate fertilizer and mineral weathering are the main sources of soil phosphorus,but the low utilization rate of phosphorus and the limited ability of crops to absorb and utilize phosphorus lead to the accumulation of soil phosphorus,which limits the growth of crops.Intercropping system can improve soil phosphorus availability.The effects of intercropping on phosphorus utilization rate were summarized.The mechanism of intercropping to improve soil phosphorus availability was reviewed from three aspects:soil microorganisms,crop roots,and changes in endogenous hormones.It is suggested that in the future,we should focus on the in-situ characterization of plant root morphology,auxin-related gene expression,soil microorganisms and related functional genes,in order to provide reference for improving phosphorus utilization rate through intercropping.

Abstract:To clarify the quantitative indicators of fresh tobacco leaf maturity,Zhongyan 100 was used as the experimental material.Mid-stem leaves with SPAD values of 10-15(S10～15),15-20(S15～20),and 20-25(S20～25)were harvested to explore the metabolomics characteristics,as well as the appearance evaluation,physical properties,chemical composition,aroma content,and sensory quality of their post-cured leaves.The results showed that the post-cured leaves of the S15～20 treatment obtained the optimal quality,including better appearance quality,good physical properties,harmonious chemical components,and the highest total amount of neutral aromatic substances,showing high maturity.According to the partial least squares discriminant analysis(PLS-DA),32 mutual differential metabolites were identified between two comparison groups,including L-tryptophan,gamma aminobutyric acid,geranic acid,pyrrole-2-carboxylic acid,trehalose,kojibiose,nicotinate D-ribonucleoside,1-methyladenosine,sphinganine,melibiitol,indole,scopoletin,18-hydroxycorticosterone,25-hydroxycholesterol,and kaempferide,et al.These differential metabolites might be key differential metabolites during the maturation process of tobacco.Then,a total of 48 significantly differential metabolites were identified across the two groups,including 11 amino acids,7 steroids,6 organic acids,6 sugars,3 alcohols,3 nucleotides,2 flavonoids,1 vitamin,and 9 other metabolites.These significantly differential metabolites were primarily enriched in pathways such as amino acid biosynthesis,ABC transporters,arachidonic acid metabolism,lysine degradation,biosynthesis of phenylpropanoids,and butanoate metabolism,which might play important regulatory roles during the maturation of tobacco leaves.

Abstract:In order to explore the effect of tobacco essential oil microcapsules on cigarette paper flavoring,firstly,tobacco essential oil was prepared by water distillation.Then complex coacervation method was employed to prepare tobacco essential oil microcapsules with tobacco essential oil as the core material,chitosan as the wall material,and span-80 as the emulsifier,and the embedding yield was determined.Subsequently,scanning electron microscopy,laser particle size analyzer and infrared spectrum analyzer were used to characterize the physical and chemical properties of microcapsules.Finally,the microcapsules were used to flavor cigarette paper,and the sensory evaluation and smoke composition analysis of the flavored cigarettes were carried out.The results showed that the average particle size of tobacco essential oil microcapsules prepared with chitosan as the wall material and tobacco essential oil as the core material was 221.1 nm,and the embedding yield was 75.3%.The prepared tobacco essential oil microcapsules showed smooth and plump spherical surface through scanning electron microscope.The infrared spectrum analysis of tobacco essential oil,chitosan and tobacco essential oil microcapsules showed that tobacco essential oil was embedded in chitosan by comparing their characteristic absorption peaks.The results of sensory evaluation showed that the flavored cigarettes were significantly improved.When the tobacco essential oil microcapsules and tobacco essential oil were compounded at a volume ratio of 1∶2,the aroma effect was more significant,and the sensory evaluation score could reach 86.6.Compared with the control(ie.cigarettes without flavoring),the contents of nicotine,alcohols,aldehydes,acids,esters and ketones in the smoke components of the cigarettes with compound flavors were increased,and the aroma,taste and strength of cigarettes were improved.

Abstract:To clarify the salt-alkali tolerance characteristics of tiger nut(Cyperus esculentus)at the seedling stage and establish precise evaluation indicators and a relevant mathematical model,18 trait indices including germination rate,plant height,root length,root number,plant biomass,plant water content,chlorophyll content,superoxide dismutase(SOD)activity,and soluble protein content were measured for 66 tiger nut germplasm resources under 5 g/kg mixed salt-alkali stress after 15 days of germination.Comprehensive analytical methods,including correlation analysis,principal component analysis(PCA),membership function,grey relational analysis,and stepwise regression analysis,were employed to assess the stress tolerance performance of different materials and establish an evaluation system.The results showed that the variation in salt-alkali tolerance coefficients among different traits ranged from 9.79%to 58.57%,with the coefficient for root dry mass exhibiting the greatest variability and that for relative water content demonstrating the smallest variability.PCA transformed the 18 original indicators into six principal components,which cumulatively accounted for 86.783%of the total variance.Based on the comprehensive evaluation D-value,the 66 germplasm resources were classified into five tolerance levels:extremely strong,strong,moderate,weak,and sensitive.Classification criteria were defined,identifying two germplasm resources with extremely strong tolerance and 12 salt-sensitive germplasm resources.Cultivars Yu Yousha 2 and Yu Yousha 3 were both classified as strongly salt-alkali tolerant materials.Using stepwise regression analysis,a mathematical model for evaluating salt-alkali tolerance at the seedling stage was established.This model demonstrates that by measuring and calculating the salt-alkali tolerance coefficients of total fresh weight,relative water content,root number,total chlorophyll content,plant height,and SOD activity,the D-value can be estimated using the regression equation to assess the salt-alkali tolerance of tiger nut germplasms at the seedling stage.This study provides essential materials,methodological support,and a robust evaluation framework for subsequent research on salt-alkali stress tolerant mechanisms and breeding of tiger nut varieties.

Abstract:Wild soybean is a close relative of cultivated soybean,which has abundant resistance alleles.In order to screen cadmium-tolerant wild soybean germplasm resources and analyze its molecular mechanism of cadmium-tolerance,205 wild soybean lines from eastern Hebei Province were selected as research materials.A hydroponic experiment was conducted to set up cadmium stress and control(without cadmium stress)with two environmental replicates in November 2022 and July 2023.The shoot fresh weight(SFW),root fresh weight(RFW),plant height(PH),root length(RL)were determined,and root shoot ratio(RSR)of fresh weight,cadmium tolerance coefficient(CTC)corresponding to each trait and cadmium tolerance evaluation value(D value)of each wild soybean strain were calculated.At the same time,genome-wide association analysis(GWAS)was carried out,and then haplotype analysis was performed on significant single nucleotide polymorphism(SNP)on chromosome 15.The results showed that the average value of seedlings traits under cadmium stress were lower than those of the control except for RSR.The results of frequency analysis showed that the CTC in the two environments showed normal distribution and genetic characteristics of quantitative traits.According to D value,13 cadmium-tolerant wild soybean germplasms were screened out.Principal component analysis(PCA)showed that 205 wild soybean lines could be divided into three groups.Linkage disequilibrium(LD)analysis showed that 205 wild soybean natural populations decayed at 100 kb.A total of 195 SNPs significantly associated with cadmium tolerance in wild soybean were detected by GWAS analysis,and a single SNP could explain 1.95％to 25.43％of the phenotypic variation.A total of 591 candidate genes were identified according to the physical location of SNPs,of which 11 candidate genes were repeatedly associated with multiple SNPs,which belonged to pleiotropic effects.More importantly,genes of two metal-tolerant proteins(MTPs)and two heavy metal-associated isoprenylated plant proteins(HIPPs)were identified according to functional annotations.They were L0C114386540(MTP 10-like),LOC114388453(MTP 10-like),LOC114369981(HIPP 36-like)and LOC114381753(HIPP 37-like),laying a foundation for elucidation of the molecular mechanism of the inheritance of cadmium tolerance in wild soybean.Haplotype analysis showed that the average CTC of haplotype 2 on chromosome 15 was the largest,which belonged to the excellent haplotype.This results provide information for analyzing the genetic mechanism of cadmium tolerance in wild soybean and provide important genetic resources for cultivating cadmium-tolerant soybean varieties.

Abstract:In order to screen the microorganisms with good control effect for the control of crop fungal diseases,the disease resistance and nano-selenization of Paenobacillus polymyxa KZJ-1 were studied.The results showed that KZJ-1 bacteriological solution had good inhibition effect on Colletotrichum micotianae,Thanatephorus cucumeris,Thielaviopsis basicola and Phytophthora parasitica,with inhibition rates of 49.78％,53.64％,46.42％and 58.85％,respectively.In addition,the strain KZJ-1 could biosynthesize nano-selenium,and the active solution of nano-selenium with different concentrations had a good inhibitory effect on Phytophthora parasitica,and the inhibitory effect was enhanced with the increase of the concentration of sodium selenite added.At the same time,the pot experiment results showed that KZJ-1 and its nano-selenium active bacterial solution could effectively prevent and control tobacco black shank disease and promote the growth of tobacco plants.The disease index of tobacco black shank disease treated with nano-selenium active bacterial solution was the lowest after 7 days of irrigation,and the control effect reached 90.23％,and the control effect decreased slightly to 83.32％after 14 days,both of which were significantly higher than that of the control.The growth rate of plant height,maximum leaf length and maximum leaf width were 16.21％,31.74％and 33.61％,respectively.It can be seen that the biosynthesis of nano-selenium by strain KZJ-1 enhanced the disease resistance and growth promotion ability of the original strain,and had certain practical application value in production.

Abstract:In order to provide scientific basis for protection,introduction and transplantation of Cercis glabra,the dominant environmental factors which affected the geographical distribution of Cercis glabra and the variation trend of potential suitable areas of Cercis glabra in modern and future periods were researched.Based on the 329 distribution records of Cercis glabra in China,3 topographic variables,19 climate variables in modern times and future climate scenarios of low greenhouse gas emissions(ssp 126),moderate greenhouse gas emissions(ssp245),high greenhouse gas emissions(ssp5 85)in the shared socio-economic pathway(SSP),the dominant environmental factors which affected the geographical distribution of Cercis glabra were analyzed,and then the distribution,area,spatial pattern change,centroid migration trend of potential suitable areas of Cercis glabra were predicted by MaxEnt model and ArcGIS software in modern times and future climate scenarios.The results showed that the most important environmental factors were min temperature of coldest month(Bio6),annual precipitation(Bio12)and mean diurnal range(Bio2)for the distribution of potential suitable areas of Cercis glabra,the optimal ranges were-5.5-5.0 ℃,less than 1 750 mm,7.1-9.8 ℃ respectively.The total potential suitable area of Cercis glabra was 231.46×10 4 km2 in modern times,and mainly distributed in middle-south of East China,most areas of Central China,middle-north of South China,east of Southwest and Northwest China,and the high,moderate,low suitable areas accounted for 24.66％,35.21％and 40.13％respectively.In different periods in future climate scenarios,the spatial distributions of suitable areas are similar to modern times,but the total suitable areas are more than modern times,in the climate scenarios of ssp 126,ssp245,ssp585,the total potential suitable areas will increase by 0.49％,5.02％,4.64％in 2050s(2041-2060),and increase by 2.93％,4.47％,5.45％in 2070s(2061-2080);Under the climate scenarios of ssp245 and ssp585,the newly increased rates of the suitable areas are 0.88-1.82 percentage points higher than those in the same period of ssp 126 in 2050s and 2070s,while the lost rates are comparable or slightly smaller;Generally,the newly increased rate is 4.80％-6.71％,and the lost rate is 3.37％-4.65％,it is mainly reflected in the increase of the moderate suitable areas and the decrease of the high suitable areas;The potential suitable areas of Cercis glabra will migrate northward slightly as a whole,and the migration distances are less than 1 latitude;While its distribution center will move to northwest or southwest less than 300 km,then transfer to the border region in the south of Chongqing,north of Guizhou Province,southeast of Sichuan Province,and the meridional movements are more than latitudinal movements significantly,meanwhile,the movement distances in 2070s are less than 2050s.It showes that in the future,the meridional changes of climate environment are more than latitudinal changes,and the migration distances of the distribution centers will show a reducing trend over time;Under the climate with moderate and high greenhouse gas emissions,the climate environment will be more conducive to expansion of the suitable areas of Cercis glabra.

Abstract:To investigate the effects of Artemisia argyi powder on production performance,nutrient apparent digestibility,antioxidant function and the number of fecal microorganisms of fattening pigs,48"Changbai×Dabai"binary fattening pigs with body weight of 50.0 kg were randomly divided into 4 groups:the control group was fed with basal diet only;the experimental groups were added with 2%,4%and 6%Artemisia argyi powder,which were recorded as AAP-1 group,AAP-2 group and AAP-3 group,respectively.The feeding experiment was conducted from May to July 2024,and the indexes were measured after the end.The results showed that in terms of groduction performance,the final weight of the AAP-2 group and the average daily gain of the three experimental groups were significantly improved.The final weight and average daily gain of the AAP-2 group were 10.26%and 19.10%higher than those of the control group,respectively.At the same time,the feed-weight ratio of the AAP-2 group and the diarrhea rate of the three experimental groups were significantly lower than those in the control group,with feed-weight ratio and diarrhea rate of the AAP-2 group decreased by 12.03%and 23.83%,respectively.In terms of nutrient apparent digestibility,compared with the control group,the apparent digestibility of calcium,crude protein and crude fat in the three experimental groups was significantly increased.Among them,the AAP-2 group showed the greatest improvement,with the digestibility of calcium,crude protein,and crude fat increased by 16.82%,10.14%,and 13.48%,respectively,compared to the control group.In terms of antioxidant function,the activities of catalase,glutathione peroxidase,superoxide dismutase,and total antioxidant capacity in the AAP-2 group were 36.77%,21.13%,20.36%,44.80%higher than those in the control group,respectively.The content of malondialdehyde decreased by 25.70%compared with the control group.In terms of the number of fecal microorganisms,the number of Lactobacillus and Bifidobacterium in the AAP-2 group increased by 19.61%and 11.85%,respectively,compared with the control group,while the number of Escherichia coli and Salmonella decreased by 11.18%and 22.09%,respectively.In summary,the addition of 4%Artemisia argyi powder can improve production performance,increase nutrient apparent digestibility,enhance antioxidant function,and increase the number of beneficial bacteriaand reduce the number of harmful bacteria in feces of fattening pigs.

Abstract:To provide scientific basis and technical support for green prevention and control of rice planthopper occurrence and sustainable production of double-cropping rice in paddy fields,field experiments on early and late rice were carried out at Funong Cooperative in Meihua Village,Xidu Town,Hengyang County,Hunan Province.With Xiangzaoxian 45(early rice)and Taiyou 553(late rice)as materials,four nitrogen application levels[early rice N0(0 kg/ha),N1(120 kg/ha),N2(150 kg/ha)N3(180 kg/ha)and late rice N0(0 kg/ha),N1(150 kg/ha),N2(180 kg/ha)and N3(210 kg/ha)]and two silicon levels[S0(0 kg/ha),S1(150 kg/ha)]were designed for the early and late rice.Under machine-transplanted conditions,field experiments were conducted to explore the effects of combined application of silicon fertilizer under different nitrogen application rates on the occurrence of rice planthoppers and rice yield in double-cropping paddy fields in southern Hunan(Hengyang).The results showed that nitrogen application rate had a significant effect on the occurrence of field rice planthoppers,rice yield and its components.With the increase of nitrogen application rate,the number of field rice planthoppers increased significantly,and the effective panicle number,grains per panicle,1 000-grain weight and yield of rice were significantly improved.Silicon application had a significant effect on the occurrence of field rice planthoppers,significantly reducing the number of field rice planthoppers.The highest insect population reduction rate of early rice could reach 56.81%,and that of late rice could reach 71.59%.The effective panicle number,grains per panicle,1 000-grain weight and yield of silicon-applied rice were all improved,but the difference was not significant.The yield increase range of early rice was 2.32%—11.57%,and that of late rice was 2.83%—9.83%.The interaction effect of nitrogen application rate and silicon application had a significant effect on the occurrence of field rice planthoppers and rice yield.The yields of N3S1,N3S0 and N2S1 were higher in both early and late rice,and there was no significant difference among them,but the number of rice planthoppers in N2S1 treatment was significantly lower than that in N3S1 and N3S0 treatments.Considering the rice yield and the control effect of rice planthoppers,it is appropriate to apply 150 kg/ha nitrogen combined with 150 kg/ha silicon fertilizer for early rice,and 180 kg/ha nitrogen combined with 150 kg/ha silicon fertilizer for late rice in Hengyang area.

Abstract:To investigate the methods for alleviating drought stress in flax and improving its drought resistance,the cultivar Jinya 10 was selected as the experimental material.At the budding stage,three treatments were designed:normal control(CK),drought stress following a spray of clear water(DS),and drought stress after spraying 50 g/ha Na2SeO3(SE).Foliar applications of water and selenium fertilizer were conducted,and after the drought period,various parameters were measured,including photosynthetic indices,chlorophyll fluorescence parameters,H2O2 content,malondialdehyde(MDA)level,antioxidant enzyme activities,osmotic adjustment substance content,nitrogen metabolism-related enzyme activities,yield,and yield components.The results revealed that drought stress at the budding stage significantly impaired plant growth and development,whereas selenium application notably mitigated the detrimental effects of drought on flax.The grain yield under the SE treatment was significantly higher,with an increase of 16.43%compared to the DS treatment,primarily due to a substantial rise in the number of capsules per plant and seeds per capsule.Exogenous selenium treatment substantially improved the net photosynthetic rate(Pn),stomatal conductance(Gs),and transpiration rate(Tr)in flax leaves under drought stress,while also increased chlorophyll content.Additionally,the maximum photochemical efficiency(Fv/Fm)and the actual photochemical efficiency of PSⅡ(ΦPSⅡ)were significantly enhanced.Selenium fertilizer also considerably enhanced the activities of superoxide dismutase(SOD),peroxidase(POD),catalase(CAT),nitrate reductase(NR),glutamine synthetase(GS),and glutamate dehydrogenase(GDH)under drought stress,with activity increases ranging from 11.19%to 20.57%.It also significantly reduced the non-photochemical quenching coefficient(NPQ),H2O2,and MDA content.Therefore,foliar application of 50 g/ha selenium fertilizer effectively alleviated the negative effects of drought stress during the budding stage on flax growth and yield by enhancing photosynthetic efficiency,optimizing chlorophyll fluorescence parameters,boosting the activity of antioxidant enzymes and nitrogen metabolism related enzymes,and decreasing reactive oxygen species and MDA levels.

Abstract:To improve the quality and usability of low-grade tobacco leaves,aroma-producing yeast(Y8-12)and different biological enzyme preparations were used to co-ferment low-grade tobacco leaves,and the best combination of microbe-enzyme preparations that could significantly improve the quality of tobacco leaves was screened.Subsequently,based on the degree of quality improvement,fermentation parameters were systematically optimized using single factor experiments combined with response surface methodology.Finally,changes in chemical composition and sensory quality before and after fermentation under optimal conditions were comparatively analyzed.The results showed that different biological enzyme preparations combined with aroma-producing yeast fermentation could effectively improve the quality of tobacco leaves.Among them,the G4 group composed of cellulase+pectinase+hemicellulase+lipase+aroma-producing yeast had the most obvious improvement effect,its quality improvement degree reached 0.94,and the content of total volatile aroma components increased to 197.57 μg/g.Through the response surface optimization combined with the actual production operation,the optimum process conditions were determined as follows:Fermentation time 4 d,fermaentation temperature 37℃,enzyme addition 0.4％.Under these conditions,the quality improvement degree increased to 1.15.After fermentation,the reducing sugar,chlorine and total sugar contents increased by 18.28％,-13.33％and 9.62％,respectively.The content of characteristic aroma substances such as phenylethanol,4-oxo-isophorone,geranylacetone,megastigmatrienone and phenethyl acetate were increased significantly.In summary,microbe-enzyme synergistic fermentation under suitable conditions offers a rapid and effective strategy for improving low-grade tobacco leaves and provides a reference for microbial applications in the tobacco industry.

Abstract:In order to study the mitigation effect of Bacillus on salt-alkali stress of maize at germination stage,maize with different salt-alkali tolerance(Kennian No.1,Xianyu 335,Jiaqiu 105)were used as materials,the germination test was carried out by inoculating Bacillus under salt stress(100 mmol/L NaCl)and alkali stress(60 mmol/L NaHCO3),and the effects of Bacillus on the length,antioxidant enzyme(POD,SOD,CAT,APX)activity,osmotic adjustment substance(soluble protein,soluble sugar,free proline)content,membrane lipid peroxidation(superoxide anion and malondialdehyde contents)of maize plantule and embryo root under salt-alkali stress were studied.The results showed that the growth of maize plantule and embryo root was inhibited under salt-alkali stress,and the activities of antioxidant enzymes,the contents of osmotic adjustment substances and the degree of membrane lipid peroxidation all showed an upward trend.Compared with salt-alkali stress,Bacillus could increase the length,antioxidant enzymes activities and contents of osmotic adjustment substances,and reduce the degree of lipid peroxidation of plantule and embryo root of three maize varieties under salt-alkali stress.Under salt stress,inoculation of Bacillus decreased the content of superoxide anion of maize plantule by 14.74％—49.30％,and the content of superoxide anion of maize embryo root by 0.37％—57.55％;Under alkali stress,inoculation of Bacillus decreased the content of superoxide anion of maize plantule by 18.11％—46.31％,and the content of superoxide anion of maize embryo root by 15.36％—46.83％.Overall,Bacillus can scavenge reactive oxygen species and maintain osmotic pressure balance by increasing the activities of antioxidant enzymes and contents of osmotic adjustment substances,reduce the damage caused by salt-alkali stress to maize germination,and then improve the tolerance to salt and alkali.

Abstract:In order to determine the possibility of fiber crops to repair lead-zinc contaminated soil,a pot experiment was conducted to study the growth characteristics of cotton,velvetleaf,jute and flax in polluted soil of lead-zinc mining area,and their potential to repair polluted soil in lead-zinc mining area was analyzed.The results showed that except flax,cotton,velvetleaf and jute could all grow in polluted soil of lead-zinc mining area,and the physiological and biochemical indexes including chlorophyll level,chlorophyll fluorescence parameters(Fv/Fm、ФPSⅡ)were damaged for cotton and velvetleaf,and photosynthetic parameters(AN,Gs)were damaged for cotton,velvetleaf and jute growing in polluted soil of lead-zinc mining area.The decrease of AN in cotton and velvetleaf growing in polluted soil of lead-zinc mining area was mainly caused by non-stomatal factors,while that in jute was caused by stomatal factors.In addition,the aboveground biomass of cotton and velvetleaf growing in polluted soil of lead-zinc mining area decreased significantly by 38.5％and 63.9％,respectively,and the underground biomass of velvetleaf growing in polluted soil of lead-zinc mining area decreased significantly by 29.4％,while these of jute had no change,and the tolerance to lead and zinc was ranked as jute,cotton and velvetleaf.The enrichment coefficients of lead and zinc in jute were equal to cotton and significantly higher than that of velvetleaf.The transport coefficients of lead and zinc of cotton,velvetleaf and jute were all greater than 1,but the transport coefficient of jute was larger than those of cotton and velvetleaf.It can be seen that jute is a dominant crop that can be grown on lead-zinc heavy metal polluted soil.Therefore,according to the analyses of growth conditions,photosynthetic parameters,fluorescence parameters and heavy metal enrichment ability,the cotton,velvetleaf and jute can all grow in lead-zinc polluted soil,and jute is more suitable for the remediation of heavy metal polluted soil dominated by lead and zinc.

Abstract:To investigate the effects of exogenous methyl jasmonate(MeJA)application on maturation and quality improvement in delayed-maturity upper leaves of flue-cured tobacco,a field experiment was conducted using the Yunyan 300 cultivar.Four MeJA concentrations(1,5,10,15 mmol/L)were foliar-applied for three consecutive days during the late growth stage of upper leaves.Morphological changes in the tobacco leaves were recorded,and the SPAD values of fresh leaves were measured.Additionally,the contents of conventional chemical components(starch,protein,nicotine,and water-soluble sugars)in fresh leaves were determined.After curing,the contents of conventional chemical components,physical properties,appearance quality,sensory quality,and neutral aroma components of the cured leaves were also determined and evaluated.The results showed that the leaves treated with 10 mmol/L and 15 mmol/L MeJA solution exhibited significant chlorophyll degradation and yellowing after 24 hours of the final application,with SPAD values decreasing by 13.75％and 15.33％,respectively.Compared to the control group(0 mmol/L MeJA solution,CK),exogenous applications of 5,10,15 mmol/L MeJA solution significantly reduced the contents of starch,soluble protein,reducing sugar,and total sugar in fresh leaves,while nicotine content increased significantly.Among these treatments,the 10 mmol/L MeJA solution resulted in the highest nicotine content,which increased by 48.34％compared to CK.After curing,the reducing sugar and total sugar contents in leaves treated with 10 mmol/L MeJA increased by 47.37％and 13.06％,respectively,compared to CK,indicating a more balanced chemical composition.Exogenous applications of different concentrations of MeJA solution also improved the sensory and aromatic quality of cured leaves,with an increase in neutral aromatic compounds.Notably,the content of solanone increased the most,with a 90.90％increase in leaves treated with 10 mmol/L MeJA compared to CK.In summary,exogenous MeJA solution can effectively promote the maturation and yellowing of flue-cured tobacco,as well as enhance its quality.Continuous foliar applications of 10 mmol/L MeJA solution for three days result in significant chlorosis and yellowing in fresh leaves,with the quality of cured leaves being significantly enhanced.