中文摘要：

天目山国家级自然保护区是公认的基因库。毛竹入侵天然林并替代原天然林，导致地上植物多样性下降。为了解毛竹入侵天然林后地下土壤微生物多样性的变化，分别采集了毛竹纯林、竹阔混交林和原始天然阔叶林下的土壤样品，应用建立于16SrDNAV3区片段的变性梯度凝胶电泳（DGGE）和克隆测序比对来研究土壤细菌结构的变化。结果表明，3块林地土壤16SrDNAV3区片段高达30条以上，不同林分下土壤16SrDNAV3区片段的DGGE带谱差异不大，但各有特征条带。毛竹林与阔叶林土壤的细菌结构相似度高于其与竹阔混交林的相似度。通过DGGE条带的克隆测序比对发现，调查区土壤细菌主要属于变形菌门（Proteobacterium）、厚壁菌门（Firmicutes）、酸杆菌门（Acidobacteria）、放线细菌属（Actinobacterium）和一些未命名的菌种，并且多数属无法纯培养的物种。本试验结论为：天目山自然保护区内土壤细菌多样性丰富，不同林分下的土壤细菌有各自的特征种，但非优势种；毛竹入侵未导致土壤细菌结构以及多样性发生显著变化。

英文摘要：

The Tianmu Mountain National Nature Reserve is a well-recognized Gene Pool rich in biodiversity. However, the richness of its botanical diversity is declining as a result of invasion of Phyllostachypubescens into natural broadleaf forests in some district. To investigate variation of soil bacteria community in response to the change in the aboveground vegetation, soil samples were collected at three sites, i.e. bamboo groves, mixture of bamboo and broadleaf tree and broadleaf forest. To explore variation of the soil bacterial structure, 16S-rDNA-V3-fragment-base DGGE （denaturing gradient gel electrophoresis） and clone sequence BLAST technologies were applied. Results show a total of over 30 16S rDNA V3 fragments were obtained from the soil samples, and DGGE analysis of the 16S rDNA V3 fragments revealed little variation in fingerprint, but it was found that each had its own characteristic strip. The bacterial structures in the soils of the bamboo groves and the broad-leaf forest were more similar to each other than to that of the mixed forest. The clone sequence BLAST of the DGGE bands demonstrated that the soil bacteria in the studied zone could mainly be classified as Proteobacterium, Firmicutes, Acidobacteria, Actinobacterium and some unnamed strains, and most of them were found unculturable. Based on the findings of the study, it can be concluded that the soil bacteria in the Tianmu Mountain National Nature Reserve are rich in diversity, that the bacterial communities in the soils under different forest stands have their unique species, though not dominant, and that the invasion of bamboo has not caused any significant changes in structure and diversity of the soil bacterial community.