我国中亚热带毛竹林土壤微生物群落的空间分布特征及其影响因素

Characteristics of Spatial Pattern and Influence Factors for Soil Microbial Community Structure in Moso Bamboo Forests in Middle Subtropical China

针对我国中亚热带毛竹林主要分布区，在福建、浙江、湖南、江西沿经度和纬度设置2个采样带，从5个县（市）采集了15个表层（0～20cm）土样和15个土壤剖面（0～60cm），利用磷脂脂肪酸（phospholipidfattyacids，PLFAs）和聚合酶链式反应．变性梯度凝胶电泳（polymerase chain reaction-denaturing gradient gel electrophoresis, PCR-DGGE）方法研究毛竹林土壤微生物群落空间分布特征与剖面分布特征。结果表明：毛竹林表层土壤微生物生物量和细菌α多样性指数的地带性变化趋势不显著，但不同地点的土壤微生物群落结构存在显著差异；气候因子和土壤理化性质共同影响了土壤微生物的群落结构，但气候因子的影响随土壤剖面深度增加而减弱。毛竹林土壤细菌β多样性与距离之间存在显著的衰减关系，表层（0～20cm）土壤细菌群落结构相似度（β多样性）随空间距离的衰减速率低于亚表层（20～40cm）土壤，这可能与毛竹林根系的影响有关。总体上，环境选择和扩散限制共同影响了毛竹林土壤微生物的空间分布状况。

This study was carried out in the main distribution area of Moso bamboo （Phyllostachys pubescens） in the middle subtropical zone of China, which including Zhejiang, Fujian, Jiangxi and Anhui provinces. Two sampling zones （including five sampling sites） were set according to the longitude and latitude, and 15 topsoil （0-20cm） and 15 soil profiles （0-60cm） were sampled. The spatial pattern of microbial community in the topsoil and soil profiles in Moso bamboo forests was studied based on phospholipid fatty acids （PLFAs） analysis and polymerase chain reaction-denaturing gradient gel electrophoresis （PCR- DGGE）. The results indicated that soil microbial communities in the topsoils showed no apparent zonality in the total biomass and α diversity, but the soil bacterial community structure changed significantly among different sites. The microbial community structure in the topsoil was affected by both the climatic factors and the soil physicochemical properties, and the relative influence of the climatic factors decreased with the increase of soil depth. Significant distance-decay relationship was observed in soil bacterial communities which showed the decrease in similarity of bacterial community structure （β diversity） with the increase of geographic distance. The surface layer （0-20cm） had a less slope then the subsurface layer （20-40cm）, which could be caused by the strong impact of roots under the Moso bamboo forest. Environmental selection combined with dispersal limitation influence the spatial distribution pattern of soil microbial community under Moso bamboo.