Structure And Function Of Soil Microorganisms In Sanjiangyuan Natural Reserve

Soil microbes are important parts of the ecosystem and very active in soil . Thier quantity and distributions in soil can reflect the relationship between plant nutritions and soil fertility ,and the impacts of integrated factors such as soil, vegetation and climate, etc. Therefore, the protection and research of soil microorganism diversity of ecosystem are very important for ecological protection. Sanjiangyuan Nature Reserve located in the south of Qinghai Province, belonged to the Qinghai-Tibet Plateau, the altitude vary obviously vertically ,and has an unique geographic environment. Sanjiangyuan Nature Reserve is the largest and highest Nature Reserve in China.In addition,its biological diversity is very rich and being a very sensitive ecological National Nature Reserve , which provides an ideal laboratory for global ecological change research. Qinghai-Tibet Plateau alpine grassland ecosystem has an important ecological status, because of the tough environment, fragile ecosystem and face serious degradation under the climate changes around the world, especially when integrated factors,such as the human disturbance accelerate the degradation. Researchs on the structure and function of soil microbial communities of Sanjiangyuan alpine grassland Nature Reserves ,unfold the soil microbes ecological distribution and regional specificity can provide a scientific basis for evaluating ecological evironment of the Sanjiangyuan Nature Reserve, and help us to understand the impacts of global climate changes on soil microbes of Sanjiangyuan nature reserve, then we can regulating pretective strategies base on these datas to protect the source of the Sanjiang Nature Reserve well.We use traditional isolation methods of microbes in this study to research the number of major soil microbial groups of alpine grassland biodiversity in monitoring plots of the Three Rivers Nature Reserve, and to examine its relationship with soil enzymes, microbial biomass carbon and nitrogen and the relevance of ecological factors; We use terminal restriction fragment length polymorphism (T-RFLP) molecular biology technology to study the diversity of nitrification gene(amoA), denitrification genes (nirK and nosZ), and the soil bacterial community. We also discussed the soil microbil diversity of the structure and function at different altitudes and its major impact factor. The main result are as follows:1. Soil of Qinghai-Tibet Plateau alpine grassland in Sanjiangyuan Nature Reserve was chosen to research ,for revealing the composition of soil microbial activity and microbial biomass carbon and nitrogen, and exploring the potential impacts of climate change on the microorganism. Soil samples from 4 site of different altitude, with similar texture and vegetation type, were analyzed. We test microorganism number (bacteria, fungi, actinomycetes and some physiological functions of microorganism), microbial biomass (C, N) and enzyme activities (cellulase, protease, urease, and sucrase). The results showed that all soil samples were rich in organic carbon and nutrients, the number of microorganisms as bacteria> actinomycetes> fungi, the main function of the number of microbial flora were ammonifiers> aerobic azotobacteria> nitrate bacteria> nitrobacteria , and there were signicant difference in microbial biomass (C, N) among those samples. Correlation analysis showed that the altitude had negative correlation with all factors except nitrite bacteria, and the altitude have negative correlation significantly with bacteria and ammonifiers. The altitude have negative correlation significantly with aerobic azotobacteria and nitrate bacteria. Therefore, the increasing temperature might affecte the activity of microorganisms in soil of Qinghai-Tibet Plateau alpine grassland in Sanjiangyuan Nature Reserve significantly.2. We concluded that genomic DNA can be extracted from soil effectively in a short time with 'Ultra clean soil DNA Isolation Kit' , and without special equipments. High quality DNA can be used in detecting community and diversity of soil microorganism, it is also helpful for studying metabolism pathway of function microbes.3. We study the amoA bacteria community structure and diversity of five soil samples, which vertically distributed in Sanjiang cold grassland ranged from altitude, T-RFLP method was used for analysis. The results showed that there were high similarity between neighborhood samples, geography distance might the main factor upon diversity of amoA bacteria community. amoA bacteria diversity increase with altitude increasing, the highest diversity was observed in sample ZD-1 and the lowest diversity happened in sample GH. The correlativity analysis between the T-RFs diversity indexe H' of amoA bacteria and soil geochemistry factors showed that the T-RFs diversity indexe H' of amoA bacteria is significant correlative with altitude, therefore, the increasing temperature might have definite influence on amoA bacteria diversity.4 We applied nirK and nosZ genes for study firstly, with T-RFLP techniques to evaluate the five plots denitrification microbial diversity and community structure of above sea level of vertical distribution of geo-ecological zone of alpine grassland Sanjiangyuan Nature Reserve. The results showed that there were high similarity between denitrifying bacteria. nirK gene similar rates were lower than similar rates of nosZ genes generally. nirK gene from the nearer plot has a higher similaritie rates , geographical distance may be the main factor which affected the diversity and the distribution of denitnfication nirK gene of flora.The similar rates of the nosZ gene in samples has not much differences , and nosZ gene distance has little relationship relevance with distribution. nirK gene and nosZ gene are in line with an elevation gradient according to the cluster. the highest nirK denitrifying bacteria diversity was observed in sample CD-like gene, and the lowest diversity happened in sample MD; its highest uniformity is in sample GH plot, and the lowest is in the sample MD; the diversity of nosZ gene is the highest in GML sample, and the lowest is in MD sample; that is to say the diversity of denitrifying bacteria associated with the change of altitude was not obvious, while the analysis of T-RFs nitrifier diversity index H 'and of soil bio-geo-chemical of the relevant factors also found that nirK and nosZ gene diversity index H 'and soil water content showed an extremely significant positive correlation;thus it can be infered that the changes in soil moisture have a certain impact on the diversity of denitrifying bacteria5. By using of T-RFLP techniques ,we can evaluated the distribution of bacterial community structure and diversity from four soil samples of Sanjiangyuan alpine meadow along an altitudinal gradient.The results showed that the plot with altitude of 4813m got a higher bacterial diversity in soil than the other plot with different altitude, and the geographical distance was the factors which affected the ecologically distribution of soil bacteria in this region. Temperature rise on the impact of the diversity of soil bacteria can not be ignored. In addition, other ecological factors are related to the diversity of soil bacterial community structure and ecological distribution, therefore,the mpact of other ecological factors on the diversity of soil bacteria can also not be ignored.