中文摘要：

以广西药用野生稻为材料,采用两种选择性的无氮培养基进行内生细菌的分离,应用IS-PCR指纹图谱方法对所分离到的内生细菌进行聚类分析。选取每个类群的代表菌株进行16S rRNA基因序列测定及生理生化鉴定,通过菌株接种水稻对所分离的内生固氮菌进行促生作用的分析。结果表明,从药用野生稻中分离纯化69株内生细菌,其中有26株内生固氮菌,其固氮酶活性在0.60～46.71μmol C2H4·m L-1·h-1。通过IS-PCR指纹图谱分析将所有供试菌株聚为11个类群及1个单菌株。16S rRNA基因序列分析及生理生化鉴定表明,所分离的内生固氮菌属于艾德昂菌属（Ideonella spp.）、阿氏肠杆菌（Enterobacter asburiae）及固氮螺菌（Azospirillum largimobile）,植物内生细菌有短小芽孢杆菌（Bacillus pumilus）、蜡样芽胞杆菌（Bacillus cereus）、大田根瘤菌（Rhizobium daejeonense）、沙芬西芽孢杆菌（Bacillus safensis）、纺锤形赖氨酸芽孢杆菌（Lysinibacillus fusiformis）、过氧微杆菌（Microbacterium paraoxydans）、类芽孢杆菌（Paenibacillus barcinonensis）及粘质沙雷菌（Serratia marcescens）等,表明广西药用野生稻内生细菌具有多样性。各内生细菌的代表菌株均具有溶磷解钾能力,其中yy34具有很强的溶磷能力,yy19、yy26及yy29具有较强的解钾能力。此外,yy05、yy16、yy19、yy25、yy29、yy34及yy49共7株菌能分泌生长素。将各内生固氮菌的代表菌株接种水稻后对水稻有着明显的促生作用,其中叶长增加了23.0%～45.2%,根长增加了19.8%～36.2%,分蘖数增加了59.9%～119.8%,全株鲜重增加了101.4%～257.0%,全株干重增加了68.4%～101.7%,根重增加了122.2%～188.9%。

英文摘要：

The endophytic bacteria isolated from Oryza officinalis growing in Guangxi were screened by two nitrogen-free media and grouped by IS-PCR DNA fingerprinting. The representa- tive strains of each group were further studied by physiological and biochemical tests, and 16S rRNA gene analysis. The possible plant growth promotion of the endophytic diazotrophs was tested in the rice. The results showed that a total of 69 endophytic bacteria including 26 endophytic diazotrophs were obtained from O. officinalis. The nitrogenase activity of the endophytie diazotro- phs ranged from 0.60 to 46.71 μmol C2H4 · mL-1 · h-1. The 69 endophytic bacteria were as- signed to 11 groups and 1 ungrouped strain by analysis of IS-PCR DNA fingerprinting. 16S rRNA gene sequencing analysis of representative strains of each group showed that the endophytic di- azotrophs were closely related to Ideonella spp., Enterobacter asburiae, Azospirillum largimobile, and the other endophytic bacteria were closely related to Bacillus pumilus, B. cereus, Rhizobium daejeonense, B. safensis, Lysinibacillus fusiformis, Microbacterium paraoxydans, Paenibacillus barcinonensis, and Serratia marceseens, which indicated the high diversity of endophytic bacteria colonized in the host plants of O. officinalis. All of the representative strains of the endoohvtic bacteria have the ability to release phosphate and potassium. Among these endophytic bacteria, strain yy34 has a great ability of phosphate releasing and strains yyl9, yy26 and yy29 have a great ability of potassium releasing. Seven strains （yy05, yy16, yyl9, yy25, yy29, yy34 and yy49） can secrete indole-3-acetic acid. The representative strains of the endophytic diazotrophs inoculated with rice significantly promoted the rice growth. The leaf length of inoculated rice in- creased by 23.0%-45.2%, the root length increased by 19.8%-36.2%, the tiller number increased by 59.9%- 119.8%, the fresh weight of rice increased by 101.4%-257.0%, the dry weight of rice increased by 68.4%-101.7%, and the root weig