若尔盖高寒草地微地形的土壤微生物群落多样性特征
Characteristics of soil microbial community diversity in Zoige alpine grassland microtopography

结合坡面微地形变化，从土壤微生物群落多样性角度研究典型缓丘区不同坡位上土壤微生物群落特征，了解微地形生境下土壤微生物群落变化趋势. 研究结果表明，土壤微生物群落培养的平均颜色变化率（AWCD）增长曲线呈现中坡位>坡顶＞下坡位＞上坡位>坡底的规律，中坡位土壤微生物群落代谢活性最高，坡底土壤微生物群落对基质的利用能力最低；在土壤微生物多样性指数比较中发现，除McIntosh均一度指数变化不显著外，其余土壤微生物多样性指数在不同坡位上存在显著差异. 其中，中坡位的Shannon丰富度指数及Simpson优势度指数最大，显著高于坡底指数值（P<0.05）；对土壤微生物群落碳源利用特征分析，氨基酸类利用率变化明显大于其他碳源，而胺类及酚酸类的利用程度较低，表明氨基酸类是土壤微生物利用的主要碳源；通过主成分分析发现，不同坡位的土壤微生物群落对碳源利用具有选择性，糖类、 氨基酸类、 聚合物类及酚酸类是对土壤微生物群落功能多样性差异贡献较大的碳源.
Combining with the change of microtopography on the slope，the characteristics of soil microbial community on different slopes in a typical slow-hill area are studied from the perspective of soil microbial community diversity，and the trends of soil microbial community in microtopography habitats are understood.The AWCD growth curve of soil microbial community development showed mid-slope>summit>downslope>upslope> bottom.The metabolic activity of soil microbial community in the mid-slope position is the highest，and the ability of the bottom soil microbial community to use the substrate is the lowest.In the comparison of the functional diversity of soil microbial community，there was a significant difference in soil microbial diversity at different slope positions，except the McIntosh index.The Shannon index and Simpson index in the mid-slope are the largest，which is significantly higher than bottom(P<0.05). Based on the analysis of the characteristics of soil microbial community carbon sources，the utilization rate of amino acids was significantly higher than other carbon sources，while the utilization of amines and phenolic acids was relatively low，indicating that amino acids are the main carbon source for soil microbial community utilization. Through the principal component analysis，it was found that the different slope positions are selective for the carbon sources of soil microbial community, and carbohydrates, amino acids, polymers, and phenolic acids contributed greatly to the differences in functional diversity of soil microbial community