Study On Microbial Ecology And Actinomycete Esources In Aline Soil Of Shaanxi Province

With the gradual expansion of the research scope of extreme environmental microorganisms,the attention of human beings to the ecological research of extreme environmental microorganisms has been increasing.In the distribution area of salinized soil in China,the largest area of the six regions including Shaanxi Province.The distribution of salinized soil in this province is mainly in Yulin area and Weinan area.The purpose of this study was to find out the distribution characteristics of microbes,especially actinomycetes,and their potential correlation with soil factors in saline soils of Shaanxi Province.At the same time,a special form and salt-tolerant actinomycetes strain was obtained by screening.This experiment involves 3 sampling areas in Shaanxi Province:north of Dingbian,Weinan and east of Dingbian.In response to these 33 sampling sites were determined from different levels,seasons,levels and standards.A total of 59 soil samples were collected,and soil salinity,pH values,enzymes and nutrients were measured.At the same time,bacteria,fungi and actinomycetes in soil samples were isolated and counted,and the dominant strains were selected at the same time.1500 strains of actinomycetes extracted were screened for salt tolerance and preliminarily classified to obtain special morphology and salt tolerance actinomycetes,and then to identify them.The following conclusions are drawn:1.Temporal and spatial distribution of microorganisms in saline soils of Shaanxi provinceUnder different division,the number of microorganism showed different distribution law.In the three major saline soil regions,the most microbial biomass is east of Dingbian,the second is north of Dingbian,Weinan is the least,as far as the type of saline soil is concerned,the number of microorganisms in soda salt soil and composite salt soil is above the single salt soil.In terms of the degree of salinization,the number of microorganism in microsalinization and mild salinization is larger than that in moderate salinization and resalinization.The number of microorganisms decreased gradually with the deepening of soil layer,and most of the microorganisms were distributed in the first layer and the second layer.From the time of sampling,the distribution of the number of bacteria and fungi was September and November were more than March and June,and in the number of actinomycetes,the distribution of bacteria was the most in March,followed by November,followed by September and the least in June2.The relationship between the number of soil factors and the number of microorganismsAccording to the analysis of soil factors,it was found that HCO3-,had the greatest influence on the number of bacteria,followed by organic matter,polyphenol oxidase,and available phosphorus.Among the negative factors affecting the number of bacteria,the most important factor was sucrase,followed by total salt,followed by pH and phosphatase.Among the factors that influence the number of fungi,the total salt is the influence from big to small,the Cl-,phosphatase,K+,CO32-,pH,sucrase,Ca2+,and the negative influence factor is SO42-,HCO3-from big to small.CO32-,organic matter,quick-acting nitrogen,Mg2+,quick-acting phosphorus,and enzyme.Among the factors that positively influence the number of actinomycetes,the influence is from large to small in order of SO42-,phosphatase,K+,Cl-,polyphenoloxidase,quick-acting nitrogen,and HCO3-.The negative effect on the number of actinomycetes was the total amount of salt3.Composition of actinomycetes in saline soils of Shaanxi province,relationship between soil factors and composition of actinomycetessIn the saline soil of Shaanxi Province,the non-streptomyces mainly belong to micromonospora,high temperature actinomycetes and micropolyspora,and there are several major groups of Streptomyces:spore group,golden group,yellow group,gray brown group,ash group and spherospora groupIn distribution,the amount of non-Streptomyces and Streptomyces in the five kinds of saline soils were as follows:Soda salt soil and compound salt soil were larger than single salt soil.Through the analysis of four kinds of soils with different salinization degrees,it was found that the soil salinization degree deepened,the soil non-Streptomyces species did not change obviously,but the number of Streptomyces groups decreased.Seasonal factors had no significant effect on actinomycetes in soil.Ca2+,organic matter,urease and HCO3-,polyphenoloxidase were the order of the positive factors affecting the genus of non-Streptomyces.The order of influence was Ca2+,organic matter,urease and HCO3-,polyphenol oxidase.Among the negative factors of non-streptomyces,the order of influence was sucrase,Na,SO42-,available phosphorus,CO32-.Among the factors that influence the population of Streptomyces,the order of influence is Mg2+,available potassium,Cl-,urease and available phosphorus.Among the negative influence factors of Streptomyces,the influence was Na,sucrose enzyme,K+,SO42-,was available nitrogen and phosphatase.4.The selection and ecological distribution of Halotolerant actinomyceteScreening and ecological distribution of salt-tolerant actinomycetes 1500 strains of the tested bacteria were screened on the liquid medium containing different concentrations of NaCl(18%and 20%respectively).The results showed that most of the actinomycetes in saline soil of Shaanxi province could grow in the environment of 10%NaCl.If the concentration of NaCl was more than 12%,the amount of actinomycetes decreased significantly.In this experiment,8 strains of actinomycetes resistant to 18%NaCl were obtained.In terms of the quantity of salt-tolerant actinomycetes in Shaanxi Province,Weinan region is the most,followed by Jingbian and Dingbian.In terms of the type of salinized soil,the most common is chlorine-sulphate soil,followed by alkali soil,that is,soda salt soil,and the least sulphate-chloride salt soil,sulphate salt soil.In terms of salinization degree,the most salinized soil was heavy salinized soil,medium salinized soil,micro-salinized soil and mildly salinized soil.5.Preliminary identification of salt-tolerant actinomycetes with special morphologyWith proper consideration of physiological and biochemical characteristics,15(including 10 special-form actinomycetes and 5 actinomycetes resistant to 18%NaCl)strains were selected from 41 special-form actinomycetes and 8 actinomycetes resistant to 18%NaCl.The 15 strains were classified and identified by DPS data processing software.The results were as follows:11f23 number,20f03 number,22fO2 number and 21f15 number belong to Streptomyces.The strains belonging to the genus Micromonospora are 10f06,10f09.The strains belonging to the genus Micropolyspora are O1f10.The strain of the genus Carburys is No.48f05,No.40f02;the strain belonging to the genus Actinosporium is 07f10;the strain belonging to the genus Cyst is the No.62a11;the remaining 4(04f09,17f02,17f06 and 46f03)are to be determined.