Study On The Prokaryotic Microbial Community Structure And Diversity Of Different Habitats Soil In Shule Upstream

The upstream of Shule River are located in the Qilian Mountains, where the precipitation is abundant and has glaciers in an area of850km2. Most area here is alpine meadows, being a good natural pasture. Through the ages, Shule River guarantees the local agriculture, livestock and basic living as the major river systems which secure the oasis in Yumen, Anxi, Dunhuang and Chijin-Huahai. In recent years, however, with the change of global climate to warm and dry, the Shule River Basin also appears ecological problems like desertification, salinization, shrinkage of wetlands and damage to biodiversity, etc, which threats the lives of local people. At present, the control and researches of Shule River Basin mainly concentrate on the aspects of development and utilization of water resources, desertification, hydrology, climate, glacier mass balance and plant and animal diversity, which has already yielded good results. Soil microbes, as an important part of the land ecosystem, not only play the role of decomposition, but also take part in soil nutrient cycling and energy flow. Being a focus of microbiological research, microbial diversity and community structure have valuable importance in the aspects of economic, ecological protection, scientific research. This experiment takes the Prokaryotic microorganisms in three habitats soil, namely, alpine periglacial (AG), alpine meadow (AM), alpine desert grassland (AD) of the upper reaches of Shule River as study object and adopts the technology of the16SrRNA gene clone library and the limitations of the bacteria and archaea fragment length polymorphism (T-RFLP) to analyze the structure composition and distribution characteristics of prokaryotic microbial community in different habitat soil. Meanwhile, this thesis also initiates the discussion of the connection between the soil physical and chemical factors and the prokaryotic microbial community composition, which provides the accumulation of knowledge to explain the interrelationship between the Prokaryotic microorganisms in the soil of the upper reaches of Shule River and its living environment. The experimental result is listed in the following:1. The structure and variation of bacterial group in different habitats soil of the upstream of Shule RiverThe phylogenetic analysis of bacterial16SrRNA shows that there are14bacterial taxonomic groups in the three habitat soil of AG, AM and AD, namely, Acidobacteria, Proteobacteria(α,β,γ,δ-), Bacteroidetes, Actinomycetes, Planctomycetes, Verrucomicrobia, Gemmatimonadetes, Firmlcutes, Chloroflexi, Cyanobacteria, Nitrospirae. Acidobacteria and proteobacteria are the dominant groups, being44.01%and31.87%.39.27%and25.2%.31.6%and21.99%in the three habitats soil of AG, AM and AD.Different habitats have significant variety in the bacterial community composition. Nitrospira could be tested in AG and AM habitats. And Cyanobacteria has distribution in both AG and AD habitats. The relative abundance of bacterial groups like Acidobacteria, Proteobacteria, Nitrospira, Verrucomicrobia, Bacteroidetes have significant variation in different habitats.(P<0.05) The community structure of bacterial in the three habitats is different, AG>AM>AD. The result shoes that the community structure of bacterial in the three habitats has a significant difference.2. The Structure and Variation of archaeal groups in different habitats soil of the upstream of Shule RiverThe phylogenetic analysis of archaeal16SrRNA shows that the structure of archaeal includes three archaeal groups of Group1.1b, Group1.1a and Group1.3in the three habitats soil of AG, AM and AD. Group1.1b is the dominant group in the three habitats soil, with abundance being64.92%.57.7%and63.06%respectively. The abundance of Group1.1a and Group1.3in the three habitats soil are lower than the abundance of group1.1b, being22.41%and12.67%.23.18%and19.12%.19.95%and16.99%respectively. The structure of archaeal in the three habitats soils has no significant variation in species. The diversity of archaeal in the three habitats soil is AG>AM>AD, but with no significant variation. The experimental results show that the archaeal structure in the three habitats soil of the upstream of Shule River has similar structure, without significant variation.To sum up, in the AG, AM and AD habitats of the upstream of Shule River, the variation of the structure of bacterial groups in soil has no significant diversity. The structure of bacterial group in different habitats soil has a significant character of spatial distribution. Compared with bacterial, the structure of archaeal group in the three habitats soil is steady, without significant variation.