This research aimed to characterize the MC1R gene polymorphism of Chinese black-plumage chicken breeds.Seven black plumage chicken breeds(Langshan,Shouguang,Dongxiang Blue-eggshell,Yanjin Black-bone,Yugan Black-bone,Hongguang black,and Xinyang black)were collected,the sequence of the MC1R gene was PCR amplified,sequenced and analyzed by bioinformatics.The complete CDS of the MC1R gene of seven breeds were all 945 by in length encoding a predicted polypeptide of 315 amino acids.A total of 10 poly-morphic sites were found in 210 sequences of seven chicken breeds,including 9 polymorphic loci in the coding region,of which seven were non-synonymous mutations that cause amino acid changes.The 14 haplotypes were observed based on 10 polymorphic sites.Dongxiang Blue-eggshell and Shouguang had two haplotypes,the other breeds all had two more haplotypes.The phylogenetic analysis revealed two groups,Group Ⅰ consisted of Xinyang black chicken,and the other six black plumage chicken breeds were distributed in Group Ⅱ.Our data suggested abundant genetic polymorphism in the chicken MC1R gene,which could be regarded as markers for the Chinese native breed and foreign blood breed of chicken.Therefore,this work will provide the theoretical basis for further evaluation studies,preservation,and utilization of Chinese black-plumage chicken breeds.
To explore the relationship between morphological phenotypes,internal organ size and immune function and specific life history phases before and after metamorphosis in rice frogs,Fejervarya multistriata,tadpoles at different developmental stages from Gosner 37-stage to Gosner 46-stage were sampled,and the varia-tions of body size,internal organ index and the responsiveness to phytohemagglutinin(PHA-P)for multiple key life history phases were measured,respectively.The results were as follows:(1)The body mass,body width,tail length,and total body length was gradually increased from Gosner stage 37 to 40-41 tadpoles,and then declined with a minimum at Gosner stage 46 froglets(P＜0.05).The snout to vent length showed the highest value at Gosner stage 42-43 tadpoles,which was significantly higher than that of Gosner stage 37 tadpoles and Gosner stage 46 froglets(P＜0.05).(2)The wet mass index of livers,fat bodies and kidneys peaked at Gosner stage 44-45 tadpoles,all showed the minimum value at Gosner stage 38-39 tadpoles(P＜0.05);The wet mass index of gill or lungs peaked at Gosner stage 37 tadpoles,which was significantly higher than that of any other developmental stage(P＜0.05);The length index of digestive tract was greatly higher at Gosner stage 37,38-39 and 40-41 tad-poles than that of Gosner stage 42-43 and 44-45 tadpoles and Gosner stage 46 froglets(P＜0.05).No significant developmental stage differences were found for the wet mass index of heart and spleen(P＞0.05).(3)The maxi-mal value for the PHA-P response of Gosner stage 37,38-39 and 42-43 tadpoles appeared 2 h,3 h,and 4 h after injection,respectively,and 4 h after injection for any other developmental stage,which was significantly higher at Gosner stage 42-43 tadpoles than that of Gosner stage 38-39 tadpoles and Gosner stage 46 froglets(P＜0.05).From aquatic to terrestrial environments,the variations of morphological phenotype occur prior to dramatic estab-lishments and reconstruction of internal organ sizes in Fejervarya multistriata,delayed and decreased immune function may impact on their successful landing as a cost.
To explore the community characteristics and diversity of Pinus thunbergii community,scientifi-cally manage P.thunbergii shelterbelt and protect the diversity of P.thunbergii community,we investigated the species composition,flora,and community type of the P.thunbergii community with the quadrat method in eight affiliated islands of Pingtan from 2018 to 2020,and analyzed the relationship between the diversity indexes and environmental factors by redundancy analysis.The results showed that:(1)There were 138 species of vascular plants belonging to 117 genera and 54 families in the study area,with few gymnosperms and ferns in total.(2)Phanerophytes(68 species)and therophytes(30 species)were high in the life form.In terms of growth form,there were 8 species of arbors,39 species of shrubs,76 species of herbs,and 15 species of vines,with more species of herbs and shrubs than arbors.(3)Both families and genera had the characteristics of tropical traits but lack Chi-nese endemic distribution.(4)Group average clustering method was used to divide the vegetation in the research area,which consisted of three formation types and nine association types.(5)In the comparison of the overall di-versity of the community,Pinus thunbergii+Acacia confusa plant formation was higher than the Pinus thunbergii+Eurya emarginata plant formation and Pinus thunbergii plant formation.The diversity indexes in the herb layer and shrub layer of each plant community were all higher than that in the tree layer.(6)The redundancy analysis showed that the soil total phosphorus,soil total potassium and slope aspect had significant effects on the diversity of P.thunbergii communities,with a total explanation of 42.3％.In conclusion,when building an island plant community dominated by P.thunbergii,it is necessary to pay attention to the use of mixed and phosphate fertiliz-ers and to allocate reasonably according to the regional microclimate conditions.
In order to breed Pinus elliottii families with excellent growth traits,based on the UAV mul-ti-spectral technology,the genetic variation analysis of the growth traits of different Pinus elliottii families was carried out.Taking 8-year-old P.elliottii forests of 20 half-sib families as the research objects,the tree height and canopy area of 11 months(except for February)in 2021 were quickly extracted by drone multi-spectroscopy,and DBH prediction model was built based on the actual measurement DBH data;the heritability and breeding values of the tree height,crown area and diameter at the breast height were estimated for each lineage of P.elliottii in different months.The results showed that:there was a strong correlation between the predicted DBH value of the established deep learning model based on the canopy area and tree height and the measured DBH true values,where R2 was 0.70 and RMSE was 1.83 cm;the heritability of the three growth traits of P.elliottii was between 0.00 and 0.40;a good genetic gain was obtained when the pedigree was selected with a 10％selection rate,and the genetic gain of the three growth traits ranged from 0.21 to 0.79(the genetic gain of crown area in November was 0.00).According to the breeding values of the crown area and tree height,family selection should be carried out.Finally,families of 1,6,8,9,10,16,18 and 20 should be considered as candidate families.The deep learning model based on the crown area and tree height of P.elliottii could be applied to predict the DBH of slash pine.Three growth traits of slash pine were controlled by moderate heritability.A good genetic gain was obtained with 10％selection intensity.Eight families were selected for simultaneous genetic improvement of the crown area and tree height.The research results can provide a reference for the breeding of pine families with excellent growth characters.
To fully grasp the basic conditions of soil nutrients and environmental quality of tea plantations in Xixiang County,23 soil samples were collected from the representative tea plantations,soil nutrients and 22 ele-ments contents were detected,and the nutrients and soil environmental quality in tea plantations of Xixiang County were evaluated according to the relevant soil environmental quality standards.The Kriging spatial interpolation method was used to analyze the distribution of soil elements of tea plantations.The results showed that:the mean value of pH,organic matter,and total nitrogen was 4.89(4.10-5.75),27.71(13.23-59.42)g·kg-1,1.39(0.74-2.02)g·kg-1,separately;the available nitrogen(N),phosphorus(P),potassium(K)and magnesium(Mg)were 62.85(18.70-212.99)mg·kg-1,46.39(0.81-163.00)mg·kg-1,115.18(50.53-365.00)mg·kg-1 and 404.96(94.41-870.52)mg·kg-1 in soil samples of tea plantations,respectively.Only 17％of soil samples in the main nutritional diagnostic indicators meet the nutrient requirements of high-quality,high-efficiency,and high-yield tea plantations.The mean value of the Nemerow multi-factor index was 0.67 for all the samples,which suggested that the overall soil environ-mental quality was at a safe level for Xixiang tea plantations.While,the niccolum(Ni),chromium(Cr),cuprum(Cu),and cadmium(Cd)contents in individual sample were slightly higher than the risk screening values.The spatial dis-tribution of 22 elements was extremely uneven in the tea plantations,and soil elements had different enrichment fea-tures in different areas of Xixiang County.The results of this study can provide a theoretical basis for nutrient man-agement,tea plantations construction,tea quality and safety improvement ofXixiang County.
In order to provide a theoretical basis for guiding the rational use of cyantraniliprole in the field,the field efficacy test of 10％cyantraniliprole OD against Chilo suppressalis was carried out in Changfeng and Huoqiu of Anhui Province by manual spraying method.By using an ultra-high performance liquid chromatog-raphy-tandem mass spectrometry(UPLC-MS/MS)method for the determination of cyantraniliprole residues in Procambarus clarkii,the bioaccumulation of cyantraniliprole in the head,tail and whole body of P.clarkii at dif-ferent application doses and different time after application was determined.The effects of different application concentrations and times on the growth indexes and final yield of P.clarkii were studied.The results showed that the control effect of 10％cyantraniliprole OD at the recommended dose of 20-40 mL per mu on C.suppressalis was greater than 80％.When the doses of 10％cyantraniliprole OD were 30 and 60 mL per mu,the bioaccumula-tion of cyantraniliprole in the head,tail and whole body of P.clarkii increased first and then decreased with time after application,and reached the highest value at day 14.The concentrations of cyantraniliprole in the head,tail and whole body of P.clarkii were 4.00,2.00 and 3.67 μg·kg-1;6.33,8.00 and 7.00 μg·kg-1,respectively,at the doses of 30 and 60 mL per mu.And the concentrations of cyantraniliprole in all samples were lower than LOQ after 35 days of application.There were no significant differences in the body weight,body length and final yield between the cyantraniliprole treatment groups and the control group(P＞0.05).
The rapid advancement of urbanization has led to serious damage to the ecological environment and a sharp decline in biodiversity.Although the areas of community parks are small,they have the largest number and great potential for protecting biodiversity.Spontaneous plants are not only an important part of plant diversity in the park,but also provide essential food sources and habitats for animals,therefore,their ecological values cannot be ignored.This paper focused on the community parks in Xicheng District of Beijing,based on the com-parative analysis of niche width,overlap index and plant diversity of spontaneous herbs,the community types of spontaneous herbs were explored to further clarify the community characteristics of spontaneous herbs in small-scale urban green space under the mode of intensive maintenance and management.The results were as fol-lows.(1)A total of 38 species of spontaneous herbs were recorded,belonging to 22 families and 36 genera.(2)Capsella bursa-pastoris,Chenopodium album,Solanum nigrum,Taraxacum mongolicum etc.had wide niche width;the niche overlap index(Oik)between the dominant species of spontaneous herbs ranged from 0 to 0.62.(3)In terms of plant diversity characteristics,the Patrick index and Shannon Wiener index of Yuetan Park were the highest,and the Pielou index of the Park in Nanlishi Road was the highest.(4)Using TWINSPAN classification method,the spontaneous herb communities were divided into 9 community types.V Chenopodium album+Capsella bursa-pastoris community accounted for the highest proportion.Finally,based on the ecological and landscape values,this paper put forward suggestions on the maintenance and management of spontaneous herbs in commu-nity parks to provide some references for building a near-natural and sustainable plant landscape.
Based on four years'phenotypic data,and combined with 13 molecular markers developed and identified in our laboratory,833 wheat germplasm resources(including 278 wheat micro-core germplasms,124 local varieties and 431 modem promoted varieties and advanced lines)were identified for pre-harvest sprouting(PHS)resistance.The results showed that the differences in relative germination index(RGI)were significant or extremely significant between the resistance and sensitive alleles(R/S)of the 13 molecular markers,respectively.Among these markers,the largest difference between R/S was identified in TaMFT-222 and TaMFT-194 markers,which U values were 14.98**and 11.30**,respectively,and reached the extremely significant level.The RGI could be reduced from 0.21 to 0.32 by the two resistant alleles,respectively.The next markers were Sdr2A,CNGC2AL,Vpl-b2,TaMKK3-A,PM19,CAPS-2AL,A17-19 and EX06323,as well as the signifiicant differences in PHS resistance were also detected among R/S alleles.The Qsd1 and Barc321 markers could also significantly distinguish PHS resistance between R/S alleles.A total of 63 germplasm resources with high PHS resistance were identified in this study.The 41 germplasms mainly including red-grained and local varieties had higher PHS re-sistance than that of the 22 germplasms mostly with the white grained.Through using hybridization combined with marker-assisted selection,the PHS resistance genes/loci were pyramided,and 12 new breeding materials with high pre-harvest sprouting resistance were created,which carried at least 3 genes/loci for PHS resistance.The re-sult can provide important genetic resources for breeding new varieties with high PHS resistance.
Organophosphorus insecticides(OPs)have been widely used to control agricultural pests,which has raised concerns about OPs residues in crops and the environment.The research group had previously isolated a highly efficient OPs degradation strain,Cupriavidus nantongensis X1T.In this study,the degradation character-istics of chiral organophosphorus pesticide profenofos by strain X1T under different substrate concentrations,bac-terial counts,pH and metal ions were measured.The results showed that strain X1T could preferentially degrade S-profenofos with high toxicity and low insecticidal activity.With the increase of substrate concentration,the degradation rate of profenofos by strain X1T gradually slowed down the optimal pH of profenofos degradation by strain X1T was 7.5;the valence state of metal ions was an important factor to affect the degradation of profenofos,of which Cr3+and Fe3+could inhibit the degradation of profenofos,while Ca2+,Mn2+,Mg2+,Co2+,Ni2+could promote the degradation of S-profenofos.Meanwhile,there was no significant difference between the degradation rate of S-profenofos and R-profenofos by the crude enzyme in strain X1T and purified enzyme opdB.The results provide a theoretical basis for bioremediation of profenofos residuals.
In order to explore the application of carbon dots(CDs)in biosensors,this paper successfully pre-pared blue fluorescent carbon dots with excellent water solubility and stable optical properties by one-step hydro-thermal synthesis using Meyerozyma guilliermondii PG-1 as raw material,and characterized CDs by transmission electron microscopy,Fourier infrared spectroscopy,X-ray electron diffraction and fluorescence spectroscopy.The obtained CDs were approximately round,with a size of about 11 nm,a large number of hydrophilic functional groups on the surface,and the strongest emission spectrum at 432 nm.CDs was further applied to the determina-tion of trace tetracycline hydrochloride(TC)in water.The results showed that TC can rapidly quench the fluores-cence of carbon dots based on static quenching and internal filtering effect,and the fluorescence quenching effi-ciency has a good linear relationship in the concentration range of 0.02-0.18 g·L-1,indicating its potential applica-tion as a fluorescent probe for TC detection.
Selenization modification can improve the biological activity of natural polysaccharides.With Huaishan yam polysaccharide(CYP)as the raw material,selenium-polysaccharide from Huaishan yam(Se-CYP)was prepared by HNO3-Na2SeO3 method.The preparation technology and α-glucosidase activity inhibition of Se-CYP were studied.The results of single factor test and orthogonal test showed that,with the α-glucosidase in-hibition rate as the index,the optimal conditions were as follows:mass ratio of CYP to Na2SeO3 was 6∶4,concen-tration of nitric acid was 1.4％,reaction time was 10 h,and reaction temperature was 80 ℃.Correlation analysis showed that the α-glucosidase inhibition rate of Se-CYP was highly positively correlated with the selenium con-tent.FTIR results showed that selenium existed in Se-CYP in the form of selenium ester,and its existence form was mainly as R1-Se=O-O-R2.Different concentrations of SE-CYP all showed strong inhibition on the α-glucosidase activity,and the higher the concentration,the higher the inhibition rate.The α-glucosidase inhibition rate of Se-CYP was higher than that of CYP at the same concentration.These results can provide a theoretical reference for screening and preparing of high activity and safe α-glucosidase inhibitors.
The algolytic strain SLW6 was screened from water and soil samples from different sources,which has the effect of algicidal activity on Anabaena flos aquatica.The morphological characteristics,physiological and biochemical identification and 16S rDNA sequence analysis of strain SLW6 were carried out.The effects of algaeclytic bacteria on algaeclytic effect of strain SLW6 in different culture periods and pH conditions were stud-ied.The pattern of dissolving Anabaena flos aquae by the strain was explored.The results showed that:strain SLW6 was a Gram-negative bacterium,negative in V-P test,gelatin liquefaction test and methyl red test,while positive in hydrogen peroxide test and nitrate reduction test;the homology between SLW6 strain and Alcaligenes faecalis(NR113606.1)strain was 99.65％;combined with morphological characteristics,physiological and bio-chemical identification and 16S rDNA sequence analysis,it was preliminarily determined that the algae lytic strain SLW6 was an alkali producing bacterium(GenBank accession number,OP363821).Ultrasound assisted hot etha-nol extraction of the chlorophyll a,determination of chlorophyll a content by spectrophotometry,and calculation of the algal dissolution rate based on the change of chlorophyll a content,the results showed that SLW6 had the best algae dissolving effect when it was in the logarithmic phase,and the algae dissolving rate was 89.45％;when pH was 7,the effect of algae dissolution was better,and the algae dissolution rate was 47.03％;the mode of action of alginolytic bacteria SLW6 on Anabaena flos aquatica was that the direct alginolytic activity is dominant and the indirect alginolytic activity is secondary.
The Chengdu-Chongqing urban agglomeration undertakes important responsibilities for economic de-velopment and ecological security.This study explored the impact and trends of landscape ecological risks caused by human activities under the background of rapid development,which is of great significance for regional planning and ecological governance.Based on the remote sensing data of land use in the Chengdu-Chongqing urban agglomeration in 2000,2010,and 2020,this study constructed an evaluation method of landscape ecological risks and human activity intensity,and revealed their spatiotemporal correlation characteristics based on the GWR model,bivariate local spatial correlation analysis,and coupling measurement.The results showed that:(l)From 2000 to 2020,the ERI in the study area gradually improved,with the characteristics of high in the middle and low on the periphery,and the central city became a low-risk area in 2020.(2)The HAI in the study area significantly increased,and its spatial distribution was relatively consistent with ERI,mainly radiating outward from the central city.(3)From 2000 to 2020,the negative cor-relation coefficient expanded from the expansion of the central city to the middle of the entire urban agglomeration.The spatial correlation between ERI and HAI gradually weakened,and the high-high aggregation area mainly concentrated in the middle of the study area,while the low-low aggregation area was distributed in the mountainous forest area.Both the low-high and high-low aggregation areas had an increasing trend.The coupling coordination degree of the two in-dicators significantly increased in 20 years,and the highly coordinated area in the central part of the study area expand-ed significantly.Properly governing ecological risks and scientifically planning development strategies can turn the contradiction between man and land into a new situation of mutual promotion.The research conclusion can provide a scientific reference for regional ecological risk governance and rational planning and development.
Yellow leaf disease caused by areca palm yellow leaf phytoplasma(AYLP)and the yellow leaf vi-rus disease caused by Areca palm velarivirus 7(APV1)are two of the most serious diseases affecting areca palm trees,causing huge economic losses to the areca palm industry in Hainan,and the establishment of rapid detection techniques is of great importance for the early warning and prevention and control of both diseases.In this study,multiplex PCR was used to detect areca AYLP and APV1 simultaneously,i.e.after the first round of nested PCR for AYLP,the multiplex PCR was used to amplify the two pathogens simultaneously,and the results were finally observed by electrophoresis.As results,by optimizing the multiplex PCR concentration system and annealing temperature,AYLP and APV1 were successfully amplified in one system,and two specific size bands of 525 bp and 311 bp were obtained.The results of multiplex PCR were in complete agreement with the results of single PCR,and compared with the single PCR assay,the multiplex PCR method streamlined the operation steps,im-proved the detection efficiency and significantly reduced the detection cost,providing a new method for the rou-tine diagnosis of areca palm yellow leaf disease and yellow leaf virus diseases.Therefore,this technique has im-portant applications in the routine detection of AYLP and APV1.
Intestinal permeability is directly related to intestinal homeostasis and individual health.At present,there is a lack of quantitative evaluation methods and reagents for intestinal permeability of fish.Serum intestinal fatty acid binding protein(I-FABP)is an important serum biological index for quantitative evaluation of intestinal permeability.In order to establish a quantitative detection method of serum I-FABP concentration in crucian carp(Carassius auratus),the I-FABP gene of crucian carp was cloned,expressed and purified in prokaryote.The rabbit and mouse polyclonal antibodies were prepared by immunizing New Zealand white rabbit and mouse with the recombinant protein,and their titers were 1∶80 000.The rabbit polyclonal antibody was used as the coating protein,and the mouse polyclonal antibody labeled with HRP was used as the enzyme labeled antibody.By optimizing the reaction conditions,a double antibody sandwich ELISA(DAS-ELISA)method based on rI-FABP was established.The linear regression equation of the standard curve was y=0.003 5x+0.036 7,the fitting degree was high,R2 was 0.999 1,and the cut-off value was 0.090 6.The intra-and inter-assay coefficient of variation was 1.17％-5.50％and 0.16％-4.78％indicating the good repeatability of established DAS-ELISA.Compared with a commercial kit,the coincidence rate among 54 samples was 100％.The DAS-ELISA detection method constructed in this study can be used for the quantitative evaluation of the intestinal permeability of crucian carp.In view of the conserva-tism of fish I-FABP,this method may be used for quantitative evaluation of intestinal permeability of other fish.
The purpose of this study is to look into the antibacterial activity of Tibetan propolis and the inhibi-tory mechanism in Haematonectria haematococca of Dendrobium nobile.To evaluate the antibacterial activity of Tibetan propolis,two types of bacteria and three types of fungi were studied with the Oxford cup method,the fungus cake method,the minimum inhibitory concentration(MIC)and the minimum bactericidal/fungicidal concentration(MBC),respectively.The hyphal morphology,growth rate,cell membrane permeability,and respiration intensity of H.haematococca after treatment with Tibetan propolis were used to investigate the antifungal mechanism.The re-sults showed that:(1)Tibetan propolis that had broad-spectrum antibacterial activity was significantly stronger than that of commercially available propolis.(2)On the five tested strains,Tibetan propolis extracted with 80％ethanol at pH 6 had the best antibacterial activity.(3)At a concentration of 10 mg·mL-1 of Tibetan propolis,the mycelial growth inhibition rate was 89％,and the EC50 was 2.552 mg mL-1;under these conditions,the morphology of the mycelium cells changed from full rupture to shriveling,which increased the cell membrane permeability and content leakage.Furthermore,the respiration intensity increased,which blocked the energy metabolism and inhibited the mycelium growth.In summary,Tibetan propolis is a natural broad-spectrum antibacterial agent with promising the development and research potential for controlling plant diseases caused by H.haematococca.
In order to improve the economic benefits of Carya illinoinensis planting,this experiment took 4-year-old fruit trees as the research object,based on the"3414"optimized fertilization program,to study the effects of nitrogen,phosphorus and potassium ratios on the role of the target forest trees,the distribution of the law.The re-sults showed that:the synergistic effect of nitrogen and phosphorus is the key,which restricts the distribution of ni-trogen,phosphorus and potassium in the kernels and leaves,of which the effect of nitrogen is more obvious,fol-lowed by phosphorus,and the recommended treatment of 14,5 and 6 was the optimal fertilization scheme,that is,804 g of urea,362-724 g of diamine phosphate and 320-640 g of potassium sulfate were applied per Carya illi-noinensis,which not only promotes the tree's healthy and sustainable growth and development,but also significantly improves the economic benefits of the growers,which has certain popularization value in actual production.
In order to effectively prevent the damage of Fusarium head blight in Chaohu City,Anhui Province,the average relative humidity,rain humidity and solar coefficient(rainy days x rainfall x the average relative humid-ity/sunshine time),rainfall and sunshine time from 2003 to 2019 were used as predictors,and the weighted contin-gency table analysis was used to predict the epidemic of Fusarium head blight before and after straw returning in 2011.The method was used to predict the occurrence of Fusarium head blight in Chaohu City,Anhui Province from 2020 to 2021.The predicted results of the model matched the actual occurrence of Fusarium head blight with a high accuracy of 100％.This method can be used to predict the occurrence degree of Fusarium head blight 50-60 d be-fore the suitable period for control of wheat scab(wheat turning green period).The prediction method of wheat scab based on weighted contingency table analysis in this study can improve the accuracy of prediction of Fusarium head blight in Chaohu City,Anhui Province,and provide some references for the control of the disease.
It is helpful to establish a reliable comprehensive evaluation model of wheat seed vigor and to the breeding of wheat varieties with high vigor by analyzing the seed vigor related indexes of different wheat varieties.After natural aging for 6 months,104 wheat materials were subjected to standard germination tests for 8 days.Germi-nation potential(X1),germination rate(X2),germination index(X3),seedling height(X4),seedling fresh weight(X5),root fresh weight(X6),root surface area(X7),root average diameter(X8),total root length(X9),and root total volume(X10)were measured.Diverse statistical methods including diversity statistics,correlation analysis,cluster analysis,principal component analysis,and membership function method were employed for a comprehensive evaluation of wheat seed vigor.The results showed significant correlations among most indicators of seed vigor,indicating infor-mation overlap.Using the membership function value method to calculate the comprehensive evaluation value(D value)of seed vigor,the 104 wheat materials were classified into four levels:high vigor,relatively high vigor,medium vigor and low vigor,with 4 materials classified as high vigor.Through stepwise regression,a mathematical evaluation model for the comprehensive assessment of wheat seed vigor was established:VP=-0.171-0.025X1-0.074 X2+0.012X4+1.923X5+1.650X6+0.004X7+0.236X8+0.048X10(R2=0.999).Using the established optimal regression equation to predict the vigor of the tested materials,the predicted value(VP)showed a highly significant positive cor-relation with the D value at the 0.001 level.The results indicated that when selecting high-vigor varieties,germination index and total root length can be overlooked,while emphasis should be placed on germination potential,germination rate,seedling height,seedling fresh weight,root fresh weight,root surface area,root average diameter,and root system total volume.This comprehensive evaluation method is more precise and effective.
In order to explore the relationship between the absorption of medium and trace elements in rice and rice quality under different rice co-cropping with shrimp modes,the field experiments were conducted in this study with different lobster species and densities.Four treatments were designed:rice monoculture(R),rice co-cropping with Procambarus Clarkii in low density(RCL),rice co-cropping with Procambarus Clarkii in high density(RCH)and rice co-cropping with Cherax quadricarinatus(RA).The results included the contents and correlation analysis between medium and trace elements and the quality of rice grain,and the economic benefits in different rice-crayfish farming model.The results showed that rice co-cropping with shrimp modes increased the contents of medium and trace elements in rice grain,especially in the contents of Fe,Ca and Mg.Compared with the R treatment,the Fe content of RCH,RCL and RA treatments increased by 52.0％,23.4％and 21.4％,respec-tively,and the corresponding values increased by 45.7％,32.1％and 22.8％for Ca,and increased by 45.0％、28.6％and 23.3％for Mg,respectively.The increase of medium and trace elements in rice was beneficial to the improvement of rice grain quality.The protein content in rice grain was positively correlated with Fe,Ca and Mg(P＜0.05),and the gel consistency was significantly positive correlation with Fe、Ca and Mg(P＜0.01).The amyl-ose content and chalkiness grain rate were significantly negative correlation with Ca(P＜0.01).The rice and shrimp co-cropping mode increased the protein content and gel consistency,decreasing the chalkiness and amyl-ose content in rice grain.RCH treatment had the best effect in enhancing the quality of rice grain.Compared with R treatment,the net benefit of RCH,RCL and RA treatments increased by 506％,314％and 429％,respectively.In general,the rice-shrimp co-cropping pattern can increase the content of medium and trace elements in rice grain and improve grain quality and economic benefits.In general,lobster species and breeding density are important factors to be taken into consideration in the integrated cultivation of rice-shrimp.
