中文摘要：

采用无氮Dbereiner培养基,从广西本地甘蔗品种桂糖28号根系分离筛选到1株高固氮活性的细菌菌株L03,对其进行形态、生理生化、16SrDNA序列的系统发育分析和固氮特性研究。结果表明,L03为植生克雷伯氏菌（Klebsiella plantica）,将该菌用蛋白胨含量为0.4g/L的Dbereiner培养基培养,当培养瓶中O2含量为2mL、温度为33℃的条件下固氮活性最高,固氮百分率达29.2%。并在连续继代13次后保持固氮能力不变。

英文摘要：

The present study was conducted to investigate the nitrogen fixation characteristics of a nitrogen fixation bacterium isolated from sugarcane.A nitrogen fixation bacterium was isolated from sugarcane variety GT28 by N-free D.o.bereiner medium.The 16S rDNA sequence,physiological and biochemical properties,and nitrogen fixation conditions required of the bacterium were analyzed.The strain was identified as the genus Klebsiella and named as Klebsiella sp.L03.The optimum conditions of nitrogen fixation by the bacterium were peptone 0.4 g/L,O2 2 mL and reaction at 33 ℃.The maximal nitrogen-fixing percertage reached 29.2%,and the nitrogen fixation activity kept constantly after 13 generations.