The Community Structure And Functional Diversity Of Soil Microbes In The Rhizosphere Of Three Plants From Fengfeng Mining Area

With the acceleration of economic development in China,the consumption of mineral resources is increasing day by day,and the ecological environment around the mining area has been seriously damaged.In the process of mining and utilization of mineral resources,a large number of heavy metal elements leak out and enter the surrounding areas through surface runoff,which results in different degrees of heavy metal pollution in the soil near the mining area.Because of the long-term,irreversible and cumulative nature characteristics of heavy metal pollution,environmental problems caused by heavy metals have attracted extensive attention.As an important part of Plant-Soil ecosystem,soil microorganism is the basis of bioremediation.Its community activity is closely related to soil health.Microbial activity plays an important role in promoting plant growth and development,and can also play a monitoring role in soil ecological micro-environment,which occupying important place in shaping the structure and function of the whole ecosystem.Study of structural and functional characteristics of microorganisms in heavy metal polluted mining areas can elucidate the ecological functions of microorganisms and are of great significance to the restoration of habitats and plant protection in polluted areas.Three kinds of common greening vegetation rhizosphere soils,Ilex chinensis,Broussonetia papyrifera and Berberis kawakamii,were selected in Fengfeng mining area of Hebei Province.This study analyzed soil microbial community and functional diversity by using phospholipid fatty acid(PLFA)and BIOLOG methods.Combined with soil environmental factors,the effects of plants and soils on microbial communities were discussed,which provided a basis for the restoration of ecological environment in heavy metal pollution areas.The main test results are as follows:1.The structure and functional of soil microbial community in Fengfeng mining area differ significantly among different plants.The content of PLFA in different plant rhizosphere soils was as follows: B.kawakamii > B.papyrifera > I.chinensis;and the utilization rate of different carbon sources(AWCD)was as follows: B.kawakamii > B.papyrifera ? I.chinensis.The soil environment of B.kawakamii is more suitable for soil microbial survival and is an ideal vegetation for restoration in mining area.2.The spatial distribution of soil microbial community structure and function in Fengfeng mining area existed space and time heterogeneous.In 2017,soil microbial community structure was abundant and carbon source utilization intensity was significantly higher than 2018.With the deepening of soil layer,PLFA species,contents and carbon source utilization rate in soil gradually decreased,and microbial activity showed as follows: 0-20 cm soil layer > 20-40 cm soil layer.3.The dominant species of soil microorganisms in Fengfeng mining area are bacteria,followed by community structure is Bacteria > Actinomycetes > Fungi > Anaerobe > Eukaryote.72 kinds of phospholipid fatty acids were detected in soil,of which 15:0 anteiso was significantly affected soil microorganisms of I.chinensis;15:0 iso,16:0 10-methyl was significantly affected soil microorganisms of B.papyrifera;16:0 iso,16:1 ?7c and 18:1 ?7c were significantly affected soil microorganisms of B.kawakamii.4.Carbohydrates and amino acids were mainly used carbon sources in the rhizosphere of I.chinensis B.papyrifera and B.kawakamii,while the utilization of phenolic acids and amines were least.Among them,the main single carbon sources used by soil microorganisms in I.chinensis are D-galactose ?-lactone,?-cyclodextrin,2-hydroxybenzoic acid,L-asparagine,L-phenylalanine and L-threonine;the main single carbon sources used by soil microorganisms in B.papyrifera are ?-methyl-D-glucoside,D-xylose/glucuron,i-erythritol and 1-phosphate glucose;and the dominant carbon sources used by soil microorganisms in B.kawakamii are D-galactose ?-lactone,liver sugar,itaconic acid,4-hydroxybenzoic acid,L-serine,L-threonine,glycyl-L-glutamic acid.5.The content of content of Cd element in the soil of Fengfeng mining area is significantly higher than the national third grade soil standard,while the contents of other heavy metals all conforms to the national environmental quality standard.PCA analysis indicated that pH,total organic carbon,soil enzymes,ammonia nitrogen and available phosphorus were the main influencing factors in Fengfeng mining area,which could reflect the soil nutrient status.6.Bacterial communities were significantly positively correlated with total organic carbon and soil enzymes,while ammonia nitrogen were significantly negatively correlated with all soil microbial communities.Additionally,the utilization of carbohydrates were significantly positively correlated pH and phosphatase,and total organic carbon and urease were significantly positively correlated with most of carbon sources.It can be found that total organic carbon and soil enzymes are the key factors affecting soil microbial communities in mining areas.7.There is a correlation between microbial community structure and catabolic function in Fengfeng mining area.The bacterial and fungi communities were positively correlated with carbohydrate and polymer carbon sources,and Gram Positive were positively correlated with carboxylic acid and amine carbon sources.