中文摘要：

以青藏高原腹地不同植被类型多年冻土区土壤细菌为研究对象,分析了可培养菌群数量、多样性和生理代谢功能的变化及其与环境因子间的关系.结果显示：从沼泽草甸到高寒荒漠,土壤水分、总碳、总氮含量逐渐降低,pH值升高,可培养细菌数量在2.97×106～2.88×107 CFU.g-1,与含水量、总碳、总氮显著正相关;Actinobacteria（51.4%）和γ-Proteobacteria（31.7%）为优势菌群,α-prote-bacteria仅在沼泽草甸中有分布,β-protebacteria、Bacterioidetes丰度与含水量、总碳、总氮间显著正相关;自沼泽到荒漠,菌群代谢活性和Shannon功能多样性指数降低,pH与Shannon指数显著负相关,继氨基酸类碳源之后,多聚物逐渐成为被细菌群落主要利用的碳源种类.研究表明,伴随冻土退化地上植被逆向演替的过程,青藏高原多年冻土地下土壤微生物群落丰度、遗传和代谢功能多样性均发生了不同程度的响应.

英文摘要：

Microbial community abundance and diversity were analysis by cultivation and BIOLOG Ecoplates methods in permafrost-affected soil,along different vegetation types in Qinghai-Tibet Plateau.The results showed that soil moisture,total carbon and nitrogen decreased from alpine swamp meadow to desert,while pH increased,forming the degradation gradient.Culturable bacterial numbers ranged from 2.97×106 to 2.88×107 CFU·g-1,positively correlated with the soil moisture,total carbon and nitrogen contents.Actinobacteria（51.4%） and γ-proteobacteria（31.7%） were the predominant phylums.α-proteobacteria was only present at swamp meadow sites while absent in others.Numbers of β-proteobacteria and bacterioidetes have a positive correlation with soil moisture,total carbon and nitrogen.Along the degradation gradient,microbial activity and Shannon index,which has a negative correlation with pH value,are both declined.The relative utilization of polymers replaced amino acids,becoming the main carbon source to microbial communities.The whole results demonstrated that accompanying by the dynamic succession of different vegetation in permafrost regions of Qinghai-Tibet Plateau,culturable bacterial abundance,activity,phylogenetic and metabolic functional diversity shifted as well.