Abstract:Taking Baiyan 7 as material,the effects of fertilization[single application of 18 000 kg/ha bio-organic fertilizer(A),single application of 225 kg/ha pasture-specific fertilizer(B),and combined application of 50%pasture-specific fertilizer(112.5 kg/ha)+50%bio-organic fertilizer(9 000 kg/ha)(C)]and planting density[4.75 million plants/ha(1),5.75 million plants/ha(2),and 6.75 million plants/ha(3)]on oat plant height,leaf area,photosynthetic characteristics,forage yield,quality,and soil physicochemical properties were analyzed,and comprehensive evaluation was conducted using membership function method to screen the optimal treatment,so as to provide theoretical basis for efficient production of oat forage and sustainable soil utilization in alpine ecological regions.The results showed that from the perspectives of oat growth,yield and nutritional quality,C1,C2 and C3 treatments performed well,overall,C2 treatment had the best performance.C2 treatment had the highest plant height,coverage,leaf area,net photosynthetic rate,transpiration rate,stomatal conductance,SPAD value,fresh grass yield,dry grass yield,crude protein content,soluble sugar content,total digestible nutrient content and relative feeding value,which significantly increased by 79.88%,44.60%,38.87%,61.30%,48.26%,38.51%,45.08%,74.05%,65.16%,70.24%,40.22%,60.90%and 42.83%,respectively,compared with CK(planting density of 4.75 million plants/ha without fertilization).C2 treatment had lower acid detergent fiber and neutral detergent fiber contents,which significantly reduced by 24.63%and 19.18%,respectively,compared with CK.Additionally,C2 treatment had second-highest crude fat content and relative forage value,which significantly increased by 104.10%and 37.66%,respectively,compared with CK.Soil physicochemical properties of C2 treatment were improved,organic carbon content was 41.80 g/kg,total nitrogen content was 3.65 g/kg,while electrical conductivity and pH value decreased.The comprehensive evaluation result showed that C2 treatment had the highest membership function value(0.83),followed by C1 treatment,while CK performed the worst.In conclusion,under the combined application of 50%pasture-specific fertilizer(112.50 kg/ha)+50%bio-organic fertilizer(9 000 kg/ha)and planting density of 5.75 million plants/ha,the oat had the best growth performance,highest forage yield and nutritional quality,and favorable soil physicochemical property,which is suitable for widespread adoption in high-altitude regions.

Abstract:Fresh fruits and vegetables,due to their high water content and vigorous respiratory metabolism,are highly prone to quality decline and spoilage after harvest.As the world's largest producer and consumer of fruits and vegetables,China has a persistently high post-harvest loss rate of fruits and vegetables.The development of efficient and safe preservation technology has become an urgent need for the industry.Coating preservation technology is a new food preservation method,which can effectively maintain the quality of fresh fruits and vegetables and extend the shelf life of fruits and vegetables.Chitosan,as a natural biopolymer,is regarded as the most promising preservation coating material due to its wide source,degradability and biosafety,as well as excellent film forming property,antibacterial activity and biocompatibility.A systematic review is conducted on the basic characteristics of chitosan and the preparation methods of coatings.The research and application of chitosan coatings in the field of fruit and vegetable preservation are described in detail.The preservation effect of chitosan coatings on fruits and vegetables is discussed from the perspectives of appearance quality,nutrients,flavor substances and shelf life,and mechanism of preservation and the key factors affecting the preservation efficiency are summarized.Finally,the preservative chitosan coating technical bottlenecks and future development directions are pointed out,with the expectation of providing theoretical references for the in-depth research and industrial application of this technology.

Abstract:By detecting the susceptibility of Magnaporthe oryzae to tebuconazole in Hainan Province and studying the fitness of resistance strains,the resistance risk of M.oryzae to tebuconazole was understood,which would provide theoretical reference for the scientific use of fungicides and resistance management.The mycelial growth rate method was used to determine the susceptibility to tebuconazole of 144 strains of M.oryzae collected and isolated from Hainan Province in 2022,and the susceptibility baseline of M.oryzae in Hainan Province to tebuconazole was established based on the susceptibility frequency distribution of the strains.Fifteen susceptible strains with low effective inhibitory mid-concentration(EC50)measured during the establishment of the susceptibility baseline were selected for resistance domestication under continuous selection pressure,and the domesticated strains were classified into resistance levels,and the genetic stability and suitability of the resistant strains as well as the cross-resistance to the fungicides pyraclostrobin,flucycloxazole,imidacloprid,fenpyroximate,and aliconazole were determined.The EC50 values of the 144 strains tested ranged from 0.176 9 to 0.998 0 μg/mL.The EC50 value of the least sensitive strain was 5.64 times that of the most sensitive strain.The average EC50 value was(0.476 3±0.174 5)μg/mL.The susceptibility frequencies of the strains were distributed in a continuous single-peak curve,and the susceptibility baseline to tebuconazole of M.oryzae in Hainan Province was 0.476 3 μg/mL.Through indoor domestication of 15 sensitive strains,a total of two resistant strains were obtained.EC50 values were 1.289 5 μg/mL and 1.868 4 μg/mL respectively,and resistance folds were 5.38 times and 6.65 times respectively,both of which were low resistance level.And after eight consecutive generations of transfer,the two resistant strains always maintained low-level resistance.The EC50 values of pyraclostrobin,epoxiconazole,prochloraz,difenoconazole,and diniconazole were measured and compared between the strains resistant to tebuconazole and their parental strains.The results showed that there was no cross-resistance in M.oryzae in Hainan Province between tebuconazole and the above chemicals.Through the in vitro fitness test of the tebuconazole-resistant strains,it was found that compared with the parental strains,the mycelial growth rate of the two resistant strains was significantly reduced,and the conidia production was reduced to varying degrees.In addition,they were more sensitive to strong acid and alkali environment,and their pathogenicity was greatly reduced.Therefore,the frequency of resistance mutations to tebuconazole in rice blast strains in Hainan Province is low,and the environmental suitability of their resistant strains is significantly reduced,resulting in a low risk of resistance.In addition,there is no cross-resistance between tebuconazole and commonly used fungicides in Hainan Province,and the development of resistance can be delayed by strategies such as cross-rotation or mixing with multi-site-of-action protectants in production.

Abstract:To explore the quality differences and its influencing factors of Lingwuchangzao different glossiness fruit[high glossiness fruit(S fruit)surface is flat and smooth,fruit shape is typical of long oval,with appearance of good quality;Low glossiness fruit(R fruit)surface is uneven,fruit shape for the top of the fruit is sharply convex or concave,with appearance of poor quality],taking 7 Lingwuchangzao plantations in Lingwu City,Ningxia as the object of investigation,the investigation recorded the tree age,seedling type,jujube hanging thickness,jujube hanging length and other indexes,and collected different glossy fruits(S,R fruits)as the experimental materials,determined its glossiness,single fruit quality,fruit transverse and longitudinal diameter,etc.,and the soluble solids,soluble sugar,vitamin C(Vc),titratable acid content and other intrinsic quality indexes of the fruits and carried out the comparison and correlation analysis.The results showed that different plantations had Lingwuchangzao fruits with different glossiness(S and R fruits),and the ratio of R fruits had a tendency to decrease with the increase of the age of the trees;the glossiness of S fruits was 1.56 times larger than that of R fruits.And single fruit quality,fruit longitudinal and transverse diameter,fruit shape index,fruit skin thickness,pulp thickness,nuclear longitudinal and transverse diameter,single nucleus quality,fruit hardness were all very significantly smaller than R fruits.S fruits had a lower vitamin C content,sugar-acid ratio,and solid-acid ratio than R fruits.However,there were no significant differences in soluble solids,soluble sugar,titratable acid,anthocyanoside content,and other indexes between the two types of fruits.There was a significant correlation between the ratios of S and R fruits in Lingwuchangzao plantations and various factors such as seedling type,tree age,jujube hanging thickness,leaf chlorophyll content,and others.In summary,Lingwuchangzao plantations have different glossiness fruit(both S fruit and R fruit).The quality of different glossiness fruit has its own advantages and disadvantages:S fruit has the advantages of good appearance quality,normal fruit shape,sweet and sour taste;R fruit has the advantages of large fruit size,high vitamin C content,good for storage and transportation.

Abstract:In order to screen endophytes of medicinal plants with good antibacterial effect against gram-positive bacteria,surface disinfection method and plate confrontation method were used to isolate and screen endophytes of rosemary with antagonistic effect against Erysipelothrix rhusiopathiae,Streptococcus and Staphylococcus.Morphological and molecular biological identification of these endophytes were conducted,and their antibacterial active substances were explored through genome analysis.The results showed that seven strains of endophytic bacteria were isolated from different tissues such as roots,stems and leaves of rosemary.A gram-positive endophyte(HNYJJ2211C)with good antibacterial effect was obtained from seven endophyte strains by plate confrontation assay.It was identified as Bacillus mojavensis(GCF000245335.1)by morphology and molecular identification,which could effectively inhibit Erysipelothrix rhusiopathiae,Streptococcus and Staphylococcus.Whole genome sequencing analysis showed that the genome size of HNYJJ2211C was 4 147 805 bp,the content of G+C was 43.8%,and the number of its coding genes was predicted to be 4 075.3 311,1 453,2 503,440 and 158 genes were annotated by COG,GO,KEGG,VFDB and CAZy respectively.AntiSMASH software predicted that there were six gene clusters related to the synthesis of secondary metabolites.Surfactin,bacillaene,fengycin,bacillibactin,subtilosin A and bacilysin were the main secondary metabolites.In the HNYJJ2211C genome,a gene called TasA was discovered,located at 24 807 14-24 814 999 bp,having a total length of 786 bp(gene2481)and encoding 261 amino acids.From the gene clusters associated with antibacterial active substances contained in its genome,it can be predicted that this strain has the potential to develop new drugs and serve as a feedable microorganism.

Abstract:In order to explore the effects of spraying prohexadione calcium under different planting densities on the agronomic traits,photosynthetic characteristics,quality and yield of sesame,and to integrate the effective cultivation measures for the mechanical harvesting of sesame through factorial experiments,with Shangzhi 196 as the test material,a two-factor split-plot experimental design was adopted.Different densities were set as the main plots(D1:180 000 plants/ha;D2:210 000 plants/ha;D3:240 000 plants/ha),and different application amounts of prohexadione calcium were set as the sub-plots(CK:0 g/ha,spraying clear water;T1:425 g/ha;T2:500 g/ha),with a total of 9 treatments.The results showed that with the increase of planting density,the stem diameter of sesame showed a gradually decreasing trend,with a decrease range of 2.01%—4.56%.The SPAD value of leaves showed a trend of first increasing and then decreasing,and the D2 treatment was the highest,which was 0.82%and 6.65%higher than those of D1 and D3 treatments respectively.The leaf area index(LAI)and chlorophyll content had similar performance patterns.The average value of the D2 treatment was 4.72%and 5.17%significantly higher than the average values of D1 and D3 treatments respectively.The net photosynthetic rate(Pn)and stomatal conductance(Gs)were significantly decreased,and the intercellular CO2 concentration increased significantly.The number of capsules per plant and the thousand-grain weight decreased obviously,with the reduction ranges being 1.28%—8.45%and 1.39%—5.92%respectively,but there was no significant effect on the quality of sesame.After spraying prohexadione calcium,with the increase of the application amount,the plant height,the height of the first capsule,and the length of the main stem fruit axis of sesame decreased significantly,with the reduction ranges being 7.89%—10.64%,11.91%—14.01%,and 5.29%—9.01%respectively.The photosynthesis was effectively enhanced.Meanwhile,the number of capsules per plant,the thousand-grain weight,and the yield were significantly increased,with the increasing ranges being 5.72%—11.14%,2.57%—6.25%,and 3.34%—6.42%respectively.The content of crude fat decreased to some extent,while the contents of linoleic acid and crude protein were effectively increased,with the increasing ranges being 2.25%—6.08%and 3.80%—8.84%respectively.Among all treatments,D1T2 treatment had the highest Pn and 1 000-grain weight,followed by D2T2 treatment,with no significant difference between the two treatments,and D2T2 treatment had the highest SPAD value,LAI,pod number per plant and yield,which significantly increased by 7.01%compared with D2CK.Comprehensive analysis shows that when the planting density is 210 000 plants/ha,spraying prohexadione calcium at a rate of 500 g/ha once at the seedling stage and once at the early flowering stage is relatively ideal for optimizing the plant type of sesame,improving the agronomic traits for mechanical harvesting,and enhancing the yield and quality.

Abstract:The phenology information of rice varies with terrain.In view of the cloudy and rainy conditions and complex terrain in the southern mountainous areas,it is of certain research value to find a remote sensing identification method for rice.With Yongshun County,a typical mountainous terrain in Hunan Province,as the research area,combined with Sentinel-1 SAR and Sentinel-2 MSI data,the time series curve was generated by the images of four key phenology periods of rice to grasp the growth trend of rice.Firstly,the object-oriented method was used to segment the images of transplanting period and harvesting period;secondly,the feature variables optimized by the feature space optimization algorithm(FSO)were input into four models for classification such as random forest(RF);finally,the results were compared.Otherwise,according to the transplanting order,the rice samples were divided into early moving and late moving samples,the images of transplanting period and harvesting period were reclassified to explore the influence of rice transplanting time on the classification of the two images.The results showed that,compared to imagery from the transplanting stage,imagery from the harvesting stage offered better classification accuracy and was more suitable for rice mapping.The object-oriented FSO-RF model achieved the best classification results for imagery during the harvest period,with an overall accuracy of 93.19%and a kappa coefficient of 0.901.The time of rice transplanting had little effect on the image classification at harvest stage,but had a great influence on the image classification at transplanting stage.The reason was that the earliest transplanted rice was easy to be similar to the spectral characteristics and texture characteristics of some dry land crops and woodlands,and there was a phenomenon of confusion and mis-classification.In order to improve the recognition accuracy of the image during the transplanting period,it is necessary to improve the time resolution of the image,add more texture features or mask the ground objects.

Abstract:Taking mechanized sorghum variety Jinza 34 as material,under the condition of an equal nitrogen application rate of 150 kg/ha,six treatments were set up,which were no application of nitrogen fertilizer(CK),application of common urea(C1),application of slow release urea(C2),application of sulphur coated urea(C3),application of Junengwang urea(C4),and application of humic acid urea(C5).The effects of the one-off basal application of different slow controlled release urea on agronomic traits,yield,nitrogen utilization efficiency and soil nitrate nitrogen accumulation were studied to provide a theoretical basis for improving nitrogen use efficiency of the one-off basal nitrogen application and reducing soil environmental pollution.The results showed that compared with CK,the ear length,grain weight per ear,1 000-grain weight and grain yield of sorghum of urea application treatments significantly increased by 8.32%—13.71%,21.05%—42.44%,5.24%—10.32%,16.08%—24.74%,and effective ear number increased by 5.09%—18.38%,respectively.The increases of sorghum yield of urea application treatments were largely due to the increases of grain weight per ear by path analysis.Compared to the C1 treatment,C3 and C4 treatments significantly increased grain weight per ear by 17.25%and 6.25%,1 000-grain weight by 4.34%and 4.83%,grain yield by 7.46%and 5.84%,and aboveground nitrogen accumulation by 17.99%and 10.00%,respectively;increased nitrogen fertilizer use efficiency(NUE)by 88.03%and 48.89%,agronomic efficiency of nitrogen fertilizer(NAE)by 53.93%and 42.15%,partial productivity of nitrogen fertilizer(NPFP)by 7.47%and 5.84%,and nitrogen uptake efficiency(NUPE)by 18.00%and 10.00%,respectively.The grain weight per ear,nitrogen accumulation in grain,aboveground nitrogen accumulation,NUE and NUPE of C3 treatment significantly increased by 10.35%,7.24%,7.27%,26.88%and 7.27%compared with C4 treatment,respectively.Meanwhile,the nitrate nitrogen accumulation in the 0-60 cm soil layer of C3 treatment significantly decreased by 8.65%—31.30%compared with the other urea application treatments,and the residual nitrate nitrogen was mainly distributed in 0-40 cm soil layer.To sum up,under the conditions of this experiment,one-off basal application of sulphur coated urea can significantly promote the nitrogen absorption of grains and aboveground part of sorghum,increase nitrogen fertilizer utilization efficiency and yield of sorghum,effectively decrease the accumulation of nitrate nitrogen in soil,reduce the risk of nitrate nitrogen washing to the deep soil layer,and is a suitable nitrogen fertilizer application method for promotion.

Abstract:Reducing the nicotine content of tobacco leaves to a level below the threshold of addiction is a measure proposed by the World Health Organization to reduce people's dependence on tobacco,but the nicotine content of existing low-nicotine varieties can not meet the preliminary standards proposed by the World Health Organization.This study explored the effect and feasibility of grafting low nicotine varieties with eggplant to reduce nicotine content,the key genes of nicotine synthesis on grafting surface were identified by PCR,and the sources of trace alkaloids in grafted tobacco leaves and their responses to varieties with different nicotine content were analyzed.The results showed that the nicotine content in middle leaves of flue-cured tobacco leaves of imported low-nicotine variety NC926 and domestic low-nicotine variety LAK326(CD-01)was 0.251 3%and 0.272 0%respectively.After grafting NC926 with eggplant,the nicotine content in fresh tobacco leaves and middle leaves of flue-cured tobacco leaves decreased to 0.039 5%and 0.046 0%respectively.After grafting LAK326 with eggplant,the nicotine content in fresh tobacco leaves and flue-cured tobacco leaves decreased to 0.037 0%and 0.039 4%respectively,which was close to or lower than the standard of 0.4 mg/g set by the World Health Organization.By comparing the expression of the key genes NtPMT1,NtPMT2,NtQPT2,NtBBLa,NtA622 of nicotine synthesis on the grafted surface of conventional high nicotine varieties and low nicotine varieties with those on the stem surface of non-grafted tobacco,it was found that the key genes of nicotine synthesis in the stem surface of high nicotine and low nicotine varieties were significantly up-regulated in different degrees after grafting,indicating that grafting measures could induce the ability of nicotine synthesis in the grafted part.It was speculated that the trace nicotine in grafted tobacco came from stem section.Moreover,varieties with different nicotine synthesis ability had different responses to grafting,and the expression of key genes of nicotine synthesis in low nicotine varieties was lower than that in high nicotine varieties.To sum up,compared with conventional high nicotine varieties grafted with eggplant,the combination of low nicotine varieties and eggplant grafting technology can further reduce the nicotine content of tobacco leaves,and the cured tobacco leaves can be close to or lower than the nicotine content limit standard set by the World Health Organization.

Abstract:The effects of sowing dates[conventional sowing date(S1)and delayed sowing date(S2)]and enhancing fragrance fertilizer[no enhancing fragrance fertilizer(conventional fertilization,F1)and enhancing fragrance fertilizer(F2)]on yield,quality and fragrance of major aromatic rice varieties[Yexiangyouyousi(V1),19xiang(V2)and Huaxiaxiangsi(V3)]were studied in Hubei Province,so as to provide a scientific basis for the production of high-quality fragrant rice.The results showed that the high temperature and heat damage could be avoided or alleviated by delaying the sowing date,and the initial heading stage was postponed to mid-to-late August after delaying the sowing date.The processing quality and appearance quality of aromatic rice improved,and the content of aromatic substance 2-AP in brown rice significantly increased by 12.14％—162.84％after delaying the sowing date.The processing quality of aromatic rice could be improved by adding enhancing fragrance fertilizer,but the appearance quality was slightly affected.Meanwhile,the content of aroma substance 2-AP in brown rice could be increased by 6.19％—40.60％.Daily maximum temperature was negatively correlated with chalky grain rate and chalkiness,total rainfall was extremely positively correlated with yield and 2-AP content in brown rice,and daily maximum temperature,daily minimum temperature and days of daily maximum temperature≥35 ℃ were extremely negatively correlated with 2-AP content in brown rice.Overall,delayed sowing date and enhancing fragrance fertilizer are beneficial to improving the processing quality and enhancing fragrance,but the enhancing fragrance fertilizer needs to be properly combined according to the characteristics of aromatic rice varieties and sowing date to achieve better results.

Abstract:This study aimed to investigate the effects of Fagopyrum dibotrys Qian Zhong extract(Qianjinqiao San)on growth performance,carcass traits,meat quality,blood biochemical indexes,antioxidant indexes and immune indexes of finishing pigs,and to explore its application effect on finishing pigs.A total of 24 fattening pigs with similar body weights(Duroc×Landrace×Large White)were randomly divided into 4 groups with 3 replicates per group and 2 pigs per replicate.The control group(R1)was fed a farage-based diet,and pigs in the experimental groups(R2,R3 and R4)were fed the basal diet supplemented with 0.3％,0.6％ and 1.2％ Qianjinqiao San.The experiment lasted for 70 days.The results indicated that compared to the R1 group,there were no significant differences in average daily gain(ADG),average daily feed intake(ADFI),and feed-to-gain ratio(F/G)among finishing pigs in groups R2,R3,and R4(P>0.05).Furthermore,the contents of umami amino acids,saturated fatty acids,monounsaturated fatty acids in muscle tissues across different groups did not show significant variation either(P>0.05);the amount of total polyunsaturated fatty acids in R3 group were significantly reduced(P<0.05).There were no significant difference in the slaughter rate,backfat thickness,pH1h,pH24 h,eye muscle area,cooked meat yield,and intramuscular fat content among the different proportion groups of Qianjinqiao San(P>0.05).In comparison to the R1 group,blood urea nitrogen levels(BUN)in the R2 group was significantly lower(P<0.05).Moreover,serum activities of catalase(CAT)and total antioxidant capacity(T-AOC)were significantly increased in both the R3 and R4 groups(P<0.05);additionally superoxide dismutase(SOD)activity levels increased by approximately 8.04％,2.66％ and 9.91％ respectively across groups R2,R3,and R4(P>0.05).The contents of immunoglobulin A(IgA),immunoglobulin G(IgG),immunoglobulin M(IgM)in the serum of R3 and R4 groups were significantly increased(P<0.05);the levels of interferon-γ(IFN-γ)in all test groups were higher than those in the control group,with R2 group showing the most significant increase of 37.43％ (P<0.05).In conclusion,the supplementation of Qianjinqiao San at concentrations ranging from 0.3％ to 1.2％ during the late fattening period does not significantly impact growth performance,carcass characteristics,or meat quality.However,it can enhance serum antioxidant capacity and improve body immunity to a certain extent.

Abstract:Mepenzolate(DPC)compounding with plant growth regulator can effectively increase cotton yield.To clarify its effect on the law of boll formation in cotton,DPC was selected to be compounded with sodium nitroprusside(CSN),brassinolide(BR),sodium naphthylacetate(SNA),and phthalanilic acid(PHA),and a single application of DPC was used as the control.Three sprays were carried out at the budding stage,the pre-boll stage and the peak boll stage,and the effects of different compound combinations on the canopy structure,spatiotemporal distribution of boll formation,endogenous hormones,and yield were analyzed.The results showed that compared with the control,the compound treatment increased the leaf area index of cotton at the flowering boll stage,resulting in a significant decrease in the light transmittance of the lower canopy.The compound treatment increased the average growth rate of each reproductive organ and increased the number of flocculent bolls,and the number of cotton bolls increased by 35.88%—46.76%compared with the control.The compound treatment had a great effect on the vertical distribution of cotton bolls,the boll proportion in the lower part decreased compared with the control,but it increased the proportion of bolls in the middle and upper parts.The contents of indole acetic acid(IAA)and abscisic acid(ABA)in leaves could be reduced by compound treatment 10 days after the first application,and the gibberellins(GA3)content of DPC compounding with BR was significantly higher than that of the control at 30 days after application,and the compound treatment could significantly regulate the increase of zeatin riboside(ZR)content.Compared with the control,the boll formation rate of the compound treatment was significantly increased by 9.97%—16.85%,the number of bolls per hectare was significantly increased by 9.20%—17.22%,and the lint yield was significantly increased by 10.33%—22.30%.In conclusion,DPC compound treatment optimizes the spatiotemporal distribution of boll formation by regulating cotton endogenous hormones,which significantly increases the boll rate and thus increases cotton yield.

Abstract:In order to determine the level and sources of soil heavy metal pollution in two typical melon fields in Xinjiang,183 soil samples were selected as the research objects,according to the Inductively Coupled Plasma Mass Spectrometry for Soil Heavy Metal Determination(DB 65T3974-2017),the content of six heavy metals,Cr,Ni,As,Cd,Pb,and Cu,in soil samples was analyzed by inductively coupled plasma mass spectrometry(ICP-MS).The single factor pollution index and Nemero comprehensive pollution index,ground accumulation pollution index,and potential ecological risk index of soil samples were calculated.A health risk assessment model was used to evaluate the pollution levels of six heavy metals in the samples,and principal component analysis was used to analyze the sources of the six heavy metals in the samples.The results showed that among the six heavy metals in the soil samples,the maximum values of As and Cd exceeded the risk screening values,indicating a relatively high degree of pollution.The Nemero comprehensive pollution index in the two production areas reached 3.74 and 1.40,respectively,indicating severe and mild pollution.In terms of land accumulation index,both production areas had the highest As pollution level.The health risks of heavy metal pollution to children were higher than those to adults,and the contribution rate of oral intake was relatively higher.Cr,Ni,and Cu in soil might be derived from parent materials,while human activities were an important source of As,Cd,and Pb in the samples.In summary,it is necessary to reduce the impact of human activities on soil As and Cd pollution in melon fields in the study area through various means.

Abstract:In order to achieve online monitoring of plastid pigments and colors in different sections of tobacco leaves during the baking process,and provide reference for the processing of different sections of tobacco leaves and the realization of intelligent baking,technologies such as chromaticity signal monitoring equipment,acetone spectrophotometer colorimetric method,and colorimeter were used to measure the chromaticity signal values,pigment content,and color parameters of different sections of tobacco leaves at key temperature points during the baking process,and analyze their changes.Correlation analysis and regression analysis methods were used to analyze the correlation between chromaticity signal values,pigments,and color parameters,and regression equations between chromaticity signal values and pigments were constructed and verified.The results showed that there were significant differences in the content of chlorophyll and carotenoids in different sections of fresh tobacco leaves during the baking process,manifested as leaf base>leaf middle>leaf tip.The correlation analysis results showed that the brightness value(L*),redness value(a*),and yellowness value(b*)of different sections of tobacco were significantly negatively correlated with the content of chlorophyll a,chlorophyll b,chlorophyll,and carotenoids;The chromaticity signal values in different sections were significantly positively correlated with brightness value(L*),redness value(a*),and yellowness value(b*),and significantly negatively correlated with chlorophyll a,chlorophyll b,chlorophyll,and carotenoid content.The regression analysis results indicated that the chromaticity signal values of tobacco leaves in different sections had a high degree of fit with chlorophyll a,chlorophyll b,chlorophyll,and carotenoid content;The regression equation validation results showed that the relative errors of chlorophyll a,chlorophyll b,chlorophyll,and carotenoid content in the leaf base were 8.19%,9.13%,8.42%,and 13.58%,respectively.The relative errors of chlorophyll a,chlorophyll b,chlorophyll,and carotenoid content in the leaf middle were 11.39%,6.63%,10.42%,and 7.63%,respectively.The relative errors of chlorophyll a,chlorophyll b,chlorophyll,and carotenoid content in the leaf tip were 11.47%,10.79%,10.21%,and 11.58%,respectively.In summary,the chromaticity signal monitoring equipment has small experimental errors,high degree of automation,and high accuracy,which can achieve rapid and accurate monitoring of pigment in different sections of tobacco during the baking process.

Abstract:To precisely determine the resistance levels of Vigna radiata to imazethapyr and imazapic,explore the underlying molecular mechanisms,and assess potential cross-resistance and multi-resistance to other herbicides,the resistance levels of 27 V.radiata varieties to imazethapyr and imazapic were measured using the agar solid medium method.Additionally,the sensitive and resistant varieties were selected to evaluate their cross-resistance and multi-resistance to other herbicides.Finally,the mechanism through which V.radiata developed resistance to imidazolinone herbicides was elucidated via acetolactate synthase gene amplification and sequence alignment analysis.The results indicated that the preliminary screening results of resistance of 27 V.radiata varieties to imazethapyr revealed that seven varieties were sensitive,while five varieties were resistant,and one variety was suspected resistant.Both imazethapyr and imazapic could inhibit the growth and development of V.radiata.The resistance results of 13 V.radiata varieties to imazethapyr showed that seven varieties were identified as sensitive,accounting for 53.85%of the total,while six varieties exhibited low-level resistance,accounting for 46.15%.Specifically,Jilü H1004 was the most sensitive variety,with a GR50 value of 18.80 mg/kg.Baolü 2016 22-2 demonstrated the highest resistance,having a resistance index(RI)of 3.63.The resistance results of 13 V.radiata varieties to imazapic showed that seven varieties(53.85%)showed high resistance and five(38.46%)displayed extremely high resistance.Pinlü 2019-26-8-17 had the highest resistance level,with a RI value of 237.85.The findings from the ALS gene sequence analysis indicated that there were no disparities in the amino acid sequences of the two ALS genes between the relatively resistant and relatively sensitive V.radiata varieties.This suggested that the variation in the resistance of V.radiata to imidazolinone herbicides was not attributable to mutations at the ALS gene site.The results of the cross-resistance analysis revealed that the relatively resistant cultivar Pinlü 2019-26-8-17 exhibited cross-resistance to choransulam-methyl and halosulfuron-methyl,with the RI values of 500.71 and 170.47,respectively.The results of the multi-resistance analysis indicated that this relatively resistant cultivar demonstrated multi-resistance to fluroxypyr,with a RI value of 4.38.However,it did not show multi-resistance to bentazone,bixlozone and lactofen.In conclusion,among the tested varieties,there were variations in the resistance levels of different V.radiata varieties to imidazolinone herbicides.Moreover,the relative resistant cultivar exhibited multi-resistance to fluroxypyr.These findings provide a theoretical reference for effectively controlling weeds in V.radiata fields.

Abstract:In order to investigate the aroma characteristics of Yunnan black tea from different production areas in Yunnan,12 tea samples from four production areas,namely,Simao in Puer,Changning in Baoshan,Menghai in Xishuangbanna and Fengqing in Lincang,were selected as materials.The headspace-solid phase microextraction(HS-SPME)combined with gas chromatography-mass spectrometry(GC-MS)was used to separate and identify the volatile components of Yunnan black tea from different production areas on a DB-WAX column,and the volatile components of Yunnan black tea were analysed by using aroma activity value(OAV)combined with chemometrics to determine the volatiles composition and aroma characteristics of Yunnan black tea from different production areas.The results showed that a total of 143 volatile substances,mainly alcohols,aldehydes,esters and olefins,were identified in Yunnan black tea from different production areas,and 50 substances(OAV≥1)contributing to the flavor of Yunnan black tea were screened out with the help of OAV,among which linalool and β-ionone had a prominent position in OAV,and were important for the composition of the flavour of Yunnan black tea from different production areas.By using orthogonal partial least squares-discriminant analysis(OPLS-DA),combined with variable importance projection(VIP),43 differential markers were screened(VIP≥1).Based on the results of OAV and OPLS-DA,12 characteristic differential substances of Yunnan black tea were screened:2-methyl butyraldehyde,benzaldehyde,heptaldehyde,Z-hex-3-en-1-ol,methyl 2-(methylamino)benzoate,dihydroactinidolide,D-limonene,(E)-3,7-dimethylocta-1,3,6-triene,β-ionone,α-lonone,dihydro-β-ionone,and P-cymene.Z-hex-3-en-1-ol contributed prominently to the clear aroma of black tea from Changning production area;dihydroactinidolide and dihydro-β-ionone contributed prominently to the floral and fruity aroma of Menghai production area,and heptaldehyde contributed prominently to the fruity aroma of Fengqing production area.Further analysis showed that the Yunnan black tea aroma types of the four production areas were mainly floral and fruity.Combined with the cluster analysis,Changning and Fengqing production areas had floral and sweet aroma,and the fruity aroma was stronger,absence of honey notes;and the differentiated compounds of Simao and Menghai production areas were more diverse,and the composite aroma was obvious,which involved the sweet aroma,honey aroma,grassy aroma,clear aroma and fat aroma.

Abstract:This study used methods such as microbial culture,target gene sequence amplification,and homology identification to isolate and identify endophytic microbes in Morus alba L.,and explored the strain types,distribution characteristics,and functional characteristics of endophytic bacteria and fungi in the roots,stems,and leaves of Yunsang No.6 mulberry.The results showed that a total of 43 endophytic bacteria belonging to 9 genera and 22 endophytic fungi belonging to 14 genera were isolated from mulberry trees.Among them,21 bacteria and 11 fungi were isolated from roots,13 bacteria and 5 fungi were isolated from stems,and 9 bacteria and 6 fungi were isolated from leaves.There were significant differences in the distribution of endophytic microbes in the roots,stems,and leaves of mulberry trees,there were Falsibacillus pallidus,Bacillus velezensis and Pseudomonas koreensis shared in the roots and stems of mulberry trees,Pantoea agglomerans,Bacillus subtilis and Pseudomonas koreensis shared in the stems and leaves,and Pseudomonas koreensis shared in the roots,stems,and leaves;Endophytic fungi Colletotrichum siamense was shared in mulberry roots and leaves,but no common fungi were found to exist in the stems and leaves,stems and roots.Further screening of functional microbes showed that 8 strains of nitrogen fixing microbes(7 bacteria,1 fungus),4 strains of phosphorus solubilizing microbes(2 bacteria,2 fungi),and 8 strains of potassium solubilizing microbes(6 bacteria,2 fungi)were obtained from 65 endophytic microbes,respectively.In summary,endophytic bacteria and fungi in mulberry trees exhibit diversity and distribution differences in roots,stems,and leaves.Among endophytic bacteria and fungi in mulberry trees,there are functional strains that can dissolve phosphorus,nitrogen,and potassium.

Abstract:Using Chaoyang seedlings of Coreopsis grandiflora as test materials,an indoor pot experiment was conducted to investigate the effects of inoculating plant growth promoting bacteria(PGPR)and foliar spraying of melatonin(MT)at concentrations of 5 μmol/L(MT1),20 μmol/L(MT2),and 50 μmol/L(MT3)under 80 mg/kg arsenic(As)stress on the growth,root architecture,chlorophyll content,chlorophyll fluorescence parameters,nutrient elements,As absorption,and antioxidant properties of C.grandiflora.The results showed that compared with the CK treatment without As stress,the overall plant height,leaf area,and total biomass(aboveground and root dry weight)of C.grandiflora were significantly reduced under As stress.Foliar spraying of different concentrations of MT and MT+PGPR treatment could alleviate the damage of As stress to C.grandiflora.Under As stress,compared with the treatment without PGPR inoculation or MT spraying,the root system configuration(total root length,total volume,total surface area,root tip number)of C.grandiflora treated with As+MT2+PGPR was significantly improved.The root activity increased by 166.1％,and the chlorophyll content,maximum photochemical efficiency(Fv/Fm)of PS Ⅱ,and photochemical quenching coefficient(qP)increased by 56.7％,15.6％,and 62.8％,respectively,while the non photochemical quenching coefficient(NPQ)decreased by 23.7％.As stress significantly reduced the nitrogen,phosphorus,and potassium content in the aboveground and root systems of C.grandiflora,while As+MT2+PGPR treatment could increase the nitrogen,phosphorus,and potassium content in the aboveground and root systems to varying degrees.At the same time,foliar spraying of different concentrations of MT and MT+PGPR could increase the As content in the aboveground and root parts of C.grandiflora,improve the As transport coefficient and enrichment coefficient,activate the activities of superoxide dismutase(SOD),catalase(CAT),ascorbate peroxidase(APX),and glutathione reductase(GR),and increase the content of ascorbic acid(As A)and glutathione(GSH)to alleviate oxidative stress on C.grandiflora.In summary,As+MT2+PGPR treatment has the best effect on improving the resistance of C.grandiflora to As pollution.

Abstract:By using Malus × robusta(CarriŠre)Rehd as the test material,the pathogenic fungi were isolated using tissue isolation method,and their pathogenicity was determined according to Koch's postulates.The morphological characteristics of the pathogenic fungi and rDNA-ITS sequence analysis were combined to identify the types of pathogenic fungi,their biological characteristics were investigated,and through indoor toxicity tests,the most virulent chemical fungicides were selected against the pathogenic fungi of Malus × robusta rot disease,in order to provide reference basis for the comprehensive prevention and control of Malus × robusta rot disease.The results showed that the two strains of pathogenic fungi HL-23 and HL-100 isolated from Malus × robusta suffering from canker were both Valsa mali.The biological characteristics of strains HL-23 and HL-100 were analyzed by measuring the colony diameter via the cross-method.The results showed that strains HL-23 and HL-100 were most suitable for cultivation on PDA medium.The optimal pH value for mycelial growth was 5.0,and the optimal temperature was 25-30℃.They were suitable for growth under 12 hours of light and dark alternation conditions,the optimal carbon source was sucrose,and the most suitable nitrogen source was ammonium dihydrogen phosphate.The toxicity of nine commonly used chemical fungicides,such as difenoconazole and azoxystrobin,against the pathogenic fungi HL-23 and HL-100 of Malus × robusta rot disease was determined through indoor plate experiments.It was found that the inhibition rates of nine fungicides on the same type of fungal strains HL-23 and HL-100 were significantly different.The best inhibition effect was difenoconazole,with EC50 values of 0.010 9-0.0110 mg/L;The second was azoxystrobin,with EC50 values of 0.015 8-0.018 1 mg/L.

Abstract:In order to clarify the synergistic effects of different adjuvants on herbicides to control weeds,three adjuvants of vegetable oil,organic silicon and inorganic salt were selected and compounded with soybean post-emergence herbicides(250 g/L fomesafen+20％quizalofop-P-ethyl)with the dosage reduced by 20％,30％and 40％,respectively,and the experiment was carried out in the tobacco field of Jiaohe City,Jilin Province.The results showed that the performance of the three adjuvants in the synergistic reduction of herbicides was vegetable oil adjuvant>silicone adjuvant>inorganic salt adjuvant.The best control effect on weeds in tobacco field was obtained by the combination of plant oil adjuvant and herbicide reduction of 20％.The fresh weight control effects on gramineous weeds,broad-leaved weeds and total grass were the highest,reaching 97.14％,93.93％and 95.00％,respectively,which were significantly higher than those of conventional herbicide treatment(CK1),with increases of 15.57,10.42 and 12.49 percentage points,respectively.At 45 days after transplanting,the plant height,leaf length and leaf width of tobacco plants treated with 20％herbicide reduction combined with vegetable oil adjuvant and silicone adjuvant were significantly higher than those of artificial weeding treatment(CK2)and water treatment(CK3).The incidence of phytotoxicity in tobacco plants decreased by 1.83-3.37 percentage points after 20％—30％reduction of herbicide combined with vegetable oil adjuvant,and the photosynthetic efficiency of lower leaves was improved.Among the treatments,the yield,average price and output value of the treatment with 20％herbicide reduction and vegetable oil adjuvant were the highest,and the output value increased by 3.82％,18.53％and 16.41％respectively compared with CK1,CK2 and CK3.Therefore,through the reasonable selection and ratio of adjuvants,the output value of tobacco can be ensured while the herbicide is reduced,which is of far-reaching significance for reducing the environmental load of chemical pesticides and maintaining ecological balance.