对采自湖北省英山县的细茎石斛[Dendrobium moniliforme (Linn.) Sw.]根、茎和叶中的内生细菌及其根围苔藓内生细菌和根围土壤细菌进行分离,并采用扩增核糖体DNA 限制性酶切分析(ARDRA)与UPGMA 聚类分析相结合的方法对这些细菌菌株进行鉴定和多样性分析;在此基础上,采用平板检测技术测定了这些细菌菌株的解磷、解钾、产生长素和嗜铁素的能力。结果显示:从细茎石斛根和茎以及根围苔藓和根围土壤中共分离获得75 株细菌菌株,从叶中未分离出内生细菌。其中,源自根和茎的内生细菌菌株分别为14 和7 株;源自根围苔藓的内生细菌菌株偏少,仅14 株;源自根围土壤的细菌菌株最多,达到40 株。75 株菌株可被分成33 个ARDRA 簇,通过16S rDNA 序列测定及比对,它们分别隶属于链霉菌属(Streptomyces)、芽孢杆菌属(Bacillus)、假单胞菌属(Pseudomonas)、拉恩氏菌属(Rahnella)、潘多拉菌属(Pandoraea)、微杆菌属(Microbacterium)、赖氨酸芽孢杆菌属(Lysinibacillus)和泛菌属(Pantoea),其中芽孢杆菌属和假单胞菌属为优势属。在75 株内生和根围细菌中,有22 株菌株兼具解无机磷和有机磷的能力、25 株菌株具有解钾能力、64 株菌株具有产生长素能力、39 株菌株具有产嗜铁素能力,其中有9 株菌株兼具解磷、解钾、产生长素和嗜铁素的能力。总体上看,细茎石斛的内生和根围细菌数量多且多样性较高,其中9 株兼具4 种促生潜力的菌株可作为促进细茎石斛生长的候选菌株。

Endophytic bacteria from root, stem and leaf of Dendrobium moniliforme ( Linn.) Sw. collected from Yingshan County of Hubei Province, endophytic bacteria from rhizosphere moss and rhizosphere bacteria from rhizosphere soil of this species were separated, and these bacterium strains were identified and their diversity were analyzed by means of a combination method of amplified ribosomal DNA restriction analysis ( ARDRA) and UPGMA cluster analysis. On these bases, abilities of solubilizing phosphorus, solubilizing potassium, producing auxin and siderophore of these bacterium strains were detected by plate detection technology. The results show that 75 bacterium strains are obtained from root and stem of D. moniliforme and its rhizosphere moss and soil, endophytic bacterium is not isolated from leaf of D. moniliforme. In which, endophytic bacteria from root and stem are 14 and 7 strains, respectively, those from rhizosphere moss are less only with 14 strains, bacterium strains from rhizosphere soil are the most with 40 strains. 75 strains are divided into 33 ARDRA clusters, by 16S rDNA sequencing and alignment, they are belonging to genera of Streptomyces, Bacillus, Pseudomonas, Rahnella, Pandoraea, Microbacterium, Lysinibacillus and Pantoea, in which, Bacillus and Pseudomonas are the dominant genera. In 75 strains of endophytic and rhizosphere bacteria, 22 strains possess double abilities of solubilizing inorganic and organic phosphorus, 25 strains do solubilizing potassium ability, 64 strains do producing auxin ability and 39 strains do producing siderophore ability, in which, 9 strains possess all abilities of solubilizing phosphorus and potassium, producing auxin and siderophore. On the whole, endophytic and rhizosphere bacteria of D. moniliforme are quantity with high diversity, in which, 9 strains with all of four plant-growth-promoting abilities can be used as candidate strains for promoting growth of D. moniliforme.