祁连山疏勒河上游芨芨草根际可培养细菌群落特征研究

Characteristics of cultivable bacterial community in rhizosphere soil of Achnatherum splendens Trin in the upper reaches of the Shule River,Qilian Mountains

以疏勒河上游不同海拔芨芨草根际土壤样品为研究对象，研究了不同海拔土样中细菌分布特征及其影响因素．结果表明：研究区域芨芨草根际土壤可培养细菌种群密度变化范围为1．7×10^7～10．8×10^7CFU·g^-1，平均值为6．4×10^7CFU·g^-1，随海拔的升高呈先下降后上升的趋势；可培养细菌数量与土壤全氮、脲酶、蔗糖酶含量呈极显著正相关关系，与有机碳、磷酸酶含量呈显著正相关关系；同时，pH值也是影响细菌数量与多样性的一个重要因素．通过16SrDNA基因测序及构建系统发育树，研究区域可培养细菌归类为15个属，其中芽孢杆菌属和假单胞菌属为优势菌属．

In this study, the bacterial distribution and diversity in rhizosphere soil of Achnatherum splendens Trin changing with altitude in the upper reaches of Shule River were studied. The study results show that the number of cultivable bacteria varied between 1.7 × 10^7 - 10.8 × 107 CFU · g^-1, with an average of 6.4 ×107 CFU· g^- 1 ; there was a tendency that the number of cultivable bacteria decreased first and then increased; there was a significantly positive correlation between the number of cultivable bacteria and soil total nitrogen, urease and su- crose ; the relationship between the number of cultivable bacteria and organic carbon and phosphatase was positive too; pH was a negative factor, which influences the number of cultivable bacteria and the diversity of bacteria. Based on 16S rDNA gene sequences and the phylogenetic tree, the cultivable bacteria in the study area include 15 genera, of which Pseudomonas and Bacillus genus are the dominate bacteria.