青藏高原昆仑山垭口不同深度土壤可培养细菌群落特征研究

Research of the soil bacteria community characteristics at different depths in Kunlun Mountains Pass,Tibetan Plateau

以青藏高原昆仑山垭口不同深度土壤样品为研究对象,研究了可培养细菌数量及多样性.结果表明：可培养细菌数量与多样性在一定程度上均与土壤深度呈负相关关系.可培养细菌数量以表层土壤最多,而细菌多样性最低.基于16S r DNA基因序列分析共发现了6个门,18个属,21种细菌,其中表层土壤Arthrobacter siccitolerans为绝对优势种,比例达95%;冻土区（0～82.15 m）之间不同土样Mycetocola miduiensis菌株所占比例较大;而冻土层以下没有明显的优势菌.冗余分析（RDA）显示：可培养细菌数量主要受土壤有机碳影响,土壤含水量则是影响细菌多样性的主要因素.

In this study,soil cultivable bacteria number and diversity at different depths in Kunlun Mountains Pass,Tibetan Plateau,were researched. The results showed that both the cultivable bacteria number and diversity index were negatively related to sampling depths to some extent. In the top soil,there was most abundance bacteria but the diversity index was lowest. There were 21 species were isolated by sequencing PCR- amplified 16 S rDNA from the soil. These species were affiliated with 18 genera belonging to α-Proteobacyeria,β-Proteobacteria,γ- Proteobacteria,Actinobacteria,Bacteroides and Firmicutes. Among them,Arthrobacter siccitolerans was the most dominant species at the topsoil,with a ratio of 95% approximately. While Mycetocola miduiensis strain had relative high properties in the range between surface and the low er bound of the sampled frozen soil. There was no obvious dominant species beneath the frozen soil in this study. RDA analysis indicated that the cultivable bacteria number was mainly controlled by soil organic carbon,butthe soil water content was the main factor to influence bacteria diversity index.