Rhizosphere Soil Fertility And Microbial Community Characteristics Of Bretschneidera Sinensis And Its Influencing Factors

Bretschneidera sinensis is one of the first-class key protected wild plants in China,which is endangered.Off site conservations is an important technical measure to save this species.In ex situ conservation,it is necessary to improve the soil to solve the nutritional problems.Soil microorganisms play an important role in the decomposition of organic matter and nutrient metabolism cycle,and are one of the evaluation indexes of soil fertility.In this study,Bretschneidera sinensis in Jiangshan xianxialing Nature Reserve was selected as the research object,and its fertility status and spatial distribution characteristics were mastered by measuring soil physical and chemical properties.The microbial community structure and influencing factors of rhizosphere soil were revealed by high-throughput sequencing,so as to provide important theoretical basis and technical support for the protection of Bretschneidera sinensis.The main achievements are as follows.(1)The soil fertility of Bretschneidera sinensis in Xianxialing Nature Reserve is generally in good condition.The average values of organic matter,total nitrogen and available potassium are 76.78 g kg^-1,3.31 g kg^-1,260.78 mg kg^-1,which can satisfy Bretschneidera sinensis growth needs.However,soil acidification is serious,with an average p H of 4.78,low soil total phosphorus content and large differences in spatial distribution,with an average of 0.33 g kg^-1.Phosphorus deficiency and soil acidification are key factors affecting the growth of Bretschneidera sinensis in this reserve.(2)Through the analysis of the spatial distribution of soil nutrients and p H in Xianxialing Nature Reserve,it is possible to establish Bretschneidera sinensis ex-situ protection bases at Longjingkeng and Hongyanding on the east side of Xianxialing Nature Reserve,and appropriately apply phosphate fertilizers to maintain the soil nutrient balance.It can be located in Biankeng and Huazhukeng in the southwest of Xianxialing Reserve to establish Bretschneidera sinensis return introduction bases,and the soil acidification improvement measures were determined.(3)The dominant bacteria in the rhizosphere soil of Bretschneidera sinensis are Proteobacteria(35.62%),Acidobacteria(24.70%)and Actinomycetes(12.28%).The dominant fungus is Ascomycota(54.51%),Basidiomycota(20.48%)and Mortierellomycota(15.36%).(4)We found that four bacteria families,i.e.,unclassified?o?Acidobacteriales,Bdellovibrionaceae,Elsteraceae and Hyphomicrobiaceae,and two fungal families,i.e.,unclassified?c?Sordariomycetes and unclassified?o?Tremellales have significantly differences between the mature and young of Bretschneidera sinensis.Among them,soil p H and AK were significantly positive with Hyphomicrobiaceae,while negative with Bdellovibrionaceae and unclassified?c?Sordariomycetes.