中文摘要：

采集3个居群的野生华石斛根系,从中分离到130株内生细菌,并对细菌进行16S r DNA序列谱系分析,结果表明：华石斛根部内生细菌主要有：芽孢杆菌属（Bacillus）、伯克氏菌属（Burkholderia）、泛菌属（Pantoea）、肠杆菌属（Enterobacter）、藤黄杆菌属（Luteibacter）、沙雷氏菌属（Serratia）和西地西菌属（Cedecea）7个属的15个种。其中优势类群为Bacillus,次优势类群为Enterobacter和Burkholderia。优势内生细菌Bacillus spp.在3个不同的居群华石斛根部均有出现,且频率相近。环境因子差异最大、附生宿主组成最相近的霸王岭与吊罗山之间,华石斛根部内生细菌群落物种组成相似性最高。说明附生宿主植物差异是附生植物根部内生细菌物种组成差异的重要驱动因子。

英文摘要：

Endophytic bacteria are equally important as mycorrhizal fungi for orchid plant species in the ecological process of seed germination and seedling establishment. To investigate diversity of endophytic bacteria associated with Dendrobium sinense,inhabiting tropical forest in Hainan Island,root samples were collected for bacteria culturing,DNA extraction,16 S rDNA amplification,and sequencing. A total of 130 strains of endophytic bacteria were isolated from the roots of D. sinense in Jianfengling,Bawangling and Diaoluoshan mountains. Phylogenetic analysis of 16 S rDNA sequences revealed that the roots-associated endophytic bacteria community was comprised of 15 species of 7 genera： Bacillus,Burkholderia,Pantoea,Enterobacter,Luteibacter,Serratia and Cedecea. Of these bacteria,Bacillus is the most frequently isolated endophytic bacterium,followed by Enterobacter and Burkholderia. All the Bacillus spp. occurred in the three habitats at a roughly equal frequency. Compositional similarity of endophytic bacterial community associated with D. sinense is highest in between the Bawangling and Diaoluoshan mountains,where similarity is lowest in their environmental factors but highest in their host plant species composition is highest in similarity. This suggests that the difference in host plants is responsible for the difference in endophytic bacterial species composition of the roots of the host plants.