【目的】了解鼎湖山早、中、后3个演替阶段的3类森林(针叶林、混交林、阔叶林)土壤细菌群落结构及其多样性,为下一步研究不同演替阶段森林土壤微生物的功能及其与植物的相互作用提供依据。【方法】在代表性林区采集土样,从中提取总DNA,利用细菌通用引物27F和1492R PCR扩增16S rDNA并构建文库。从所构建的3个文库中各挑取150个阳性克隆子并对插入片段进行测序,利用Mothur软件对所得序列进行分析。【结果】从针叶林、混交林和阔叶林文库中分别得到122、118和120条有效16S rDNA序列,各代表70、64、72个OTUs(operational taxonomic units,以97%相似性为划分标准)。分析结果显示,共检测到8个细菌门类,其中酸杆菌门(Acidobacteria)在针叶林、混交林和阔叶林土样中分别占53.3%,67.8%和60%;变形杆菌门(Proteobacteria)分别占29.5%,20.3%和32.5%;其它如厚壁菌,放线菌等均不超过10%。3类森林土壤细菌群落结构差异显著(P<0.05),3者两两间共有的OTU数量占检测到的OTU总数的比例均低于25%,其中阔叶林土壤细菌有着最高的Chao指数(414.2)和Shannon指数(3.90),及最低的Simpson优势度指数(0.0249)。【结论】鼎湖山针叶林、混交林和阔叶林3类林区土壤细菌在种群构成上差异显著,其中阔叶林土壤细菌丰富度及多样性相对较高,但3者在大类组成方面比较相似,均为酸杆菌占绝对优势,变形杆菌次之。 【Objective】 The objective of this study is to understand the bacterial community structure and diversity of three kinds of forests (coniferous forest, mixed forest, broad-leaved forest) in the three successional stages of Dinghushan, Soil microbial function and its interaction with plants provide the basis. 【Method】 Soil samples were taken from representative forest areas and total DNA was extracted from them. The 16S rDNA was amplified by PCR using bacterial universal primers 27F and 1492R and a library was constructed. 150 positive clones were picked from each of the three constructed libraries and the inserts were sequenced. The resulting sequences were analyzed by Mothur software. 【Result】 The results showed that 122, 118 and 120 effective 16S rDNA sequences were obtained from the coniferous forest, mixed forest and broadleaf forest library respectively, each representing 70, 64 and 72 OTUs (operational taxonomic units divided by 97% similarity standard). The results showed that 8 bacterial species were detected, of which Acidobacteria accounted for 53.3%, 67.8% and 60% respectively in the coniferous, mixed and broadleaf forest samples. Proteobacteria, Accounting for 29.5%, 20.3% and 32.5% respectively; others, such as Fibrobacteria, actinomycetes and the like, did not exceed 10%. The bacterial community structure of the three types of forest soils was significantly different (P <0.05). The share of OTUs shared by the two communities was less than 25% of the total number of OTUs detected. Among them, the soil bacteria had the highest Chao index 414.2) and Shannon index (3.90), and the lowest Simpson dominance index (0.0249). 【Conclusion】 The soil bacteria in Dinghu mountain coniferous forest, mixed forest and broad-leaved forest were significantly different in population composition. Among them, the soil bacteria abundance and diversity in the broad-leaved forest were relatively high. However, More similar aspects, are acid bacteria accounted for the absolute advantage, followed by Proteus.