塔里木河干流胡杨和柽柳根际土壤微生物及其垂直分布

Study on Vertical Distribution of Microorganisms in Rhizosphere of Populus euphratica and Tamarix sp.in the Lower Reaches of the Tarim River,Xinjiang

对塔里木河干流阿拉干、英苏、喀尔达依等地的胡杨（Populus euphratica）、柽柳（Tamarix sp．）的根际微生物进行了研究。结果显示：①不同种植物之间，细菌、真菌和放线菌的比例不同。胡杨和柽柳的根际细菌、真菌、放线菌的数量大小次序为：细菌〉放线菌〉真菌。②胡杨和柽柳根际微生物总数及各类群数量垂直变化规律为：在60～100cm土层中呈现递减趋势，在100—160cm随深度的增加逐渐增加，并达到峰值，然后随土层的加深而递减。③胡杨和柽柳在根际细菌、真菌和放线菌的数量上均存在极显著差异。胡杨根际微生物总量为柽柳的2倍，胡杨的根际细菌、真菌和放线菌的数量分别是柽柳的2倍、8倍和2倍。④胡杨和柽柳的根系在不同的深度，根际的细菌、真菌和放线菌的数量不同，随着土壤有机质含量、pH值和含水量的变化而变化。

In this study, the quantity, distribution pattern and composition of microorganisms in rhizosphere of Populus euphratica and Tamarix sp. in the lower reaches of the Tarim River are lueubrated. The results are as follows： ① Proportions of bacteria, fungi and actinomyces in rhizosphere of different plant species, such as Populus euphratica and Tarnarix sp. , are different, and the quantities of bacteria, fungi and actinomyces are in an order of bacteria 〉 actinomyces 〉 fungi ;② The quantitative change and the vertical distribution of all the groups of microorganisms in rhizosphere of Populus euphratica and Tarnarix sp. are that the quantity of microorganisms is in a decrease trend at soil depth range of 60 - 100 cm, but in an increase trend at soil depth range of 100 - 160 cm and to the maximum value at soil depth of 160 cm, and then in a decrease trend with the increase of soil depth at soil depth range of 160～220 cm; ③ There is a significant difference in the quantities of bacteria, fungi and actinomyces in rhizosphere of Populus euphratica and Tamarix sp. The total quantity of microorganisms in rhizosphere of Populus euphratica is twice of that in rhizosphere of Tamarix sp. , and the quantities of bacteria, fungi and actinomyces in rhizosphere of Populus euphratica are twice, 8 times and twice of that in rhizosphere of Tamarix sp. ; ④ The composition, distribution and quantity of microorganisms in rhizosphere of Populus euphratica and Tamarix sp. are different from different soil depths, and they vary with the change of organic matter content, pH value and soil moisture content.