Response Of Soil Microbial Community To Warming And Precipitation Change In Alpine Meadow On The Tibetan Plateau

Soil microorganisms play a key role in the formation of terrestrial ecosystems,driving C,N,P,S and other nutrient cycling.Soil microorganisms play an extremely important role in the growth of aboveground vegetation and the decomposition of soil organic matter.Phospholipid fatty acids(PLFA)are an important component of almost all living microbial cell membranes,and they are rapidly degraded once they die because of high rapid rate of conversion in cells.PLFA are rich in variety and structure,sensitive to environmental factors,and also have good repeatability.Therefore,PLFA analysis is an ideal technique for studying soil microorganism.As we known,The Tibetan Plateau is a unique type of ecosystem in the world,and it is very sensitive to global climate change.Much research found global warming and precipitation regimes change have a proround influence on Tibetan Plateau.Changes in soil temperature and precipitation due to global climate change would have a huge influence on soil microorganisms,above-ground vegetation,and ecosystem functions.Therefore,it is very important to explore the effects to warming and precipitation changes on soil microorganisms in alpine meadows on the Tibetan Plateau.The experiment was conducted at the research station of alpine meadow and wetland ecosystems of Lanzhou University,in Maqu County,Gannan Tibetan Autonomous Prefecture,Gansu Province.This region has the most typical alpine meadow ecosystem on the Tibetan Plateau and is an ideal place to research the response of soil microorganisms to warming and precipitation changes.In this study,our research focus on the scientific question of how the relationship between soil microorganisms and environmental factors change under different warming and precipitation change treatments.We want to illuminate the respond mechanism of soil microbial community in the context of warming and precipitation change through our long-term climate change experiment platform in Tibetan Plateau.The main results and conclusions are as follows:(1)The types and biomass of PLFAs decreased significantly under the treatment of warming and precipitation-reducing.The biomass of anaerobe,gram-positive bacteria,gram-negative bacteria,eukaryote,and the microbial group represented by unidentified PLFAs decreased significantly under precipitation-reducing treatment;the biomass of eukaryote decreased significantly under warming treatment;the biomass of actinomycetes decreased significantly under warming and precipitation-reducing treatments.(2)Soil moisture and plant biomass have significant positive correlations on the biomass of the marker PLFAs.Soil temperature,plant diversity and plant evenness had significant negative correlations on the biomass of the marker PLFAs.Soil organic matter contributed less on the biomass of the marker PLFAs.(3)Soil moisture has a significant positive correlation on microbial groups.Soil pH was significantly negatively correlated with microbial groups represented by actinomycetes,AM fungi,fungi and eukaryote.Soil temperature and plant evenness had significant negative correlations on microbial groups.This indicated that soil physical and chemical properties and above-groundvegetation have a important influence on soil microorganisms.(4)Warming and precipitation changes treatment have no significant effect on F/B ratio,and the GP/GN ratio decreased significantly under precipitation-reducing treatment.