中文摘要：

【目的】香根草（Vetiverzizanioides）是一种多年生禾本科草本植物，具有极强的生态适应性和抗逆能力，可作饲料和水土保持用。通过研究香根草联合固氮菌多样性，为进一步研究和应用打下基础。【方法】采用无氮培养基，首次从香根草中分离到47株联合固氮菌，分别应用SDS—PAGE全细胞蛋白质电泳、DNA指纹图谱、唯一碳源和16SrDNA全序列测定等方法，进行聚类和多样性分析。【结果】SDS．PAGE、IS．PCR和Bio．BIQA碳源利用的聚类结果基本一致，将供试菌株分为6个类群和4个单菌株；16SrDNA序列测定表明，从香根草中分离的菌株包括了佛莱辛草螺菌（Herbaspirillumfrisingense）、中型假食酸菌（Pseudacidovoraxintermedius）、恶臭假单胞菌（Pseudomonasputida）、荧光假单胞菌（Pseudomonasfluorescens）、越南伯克氏菌（Burkholderiavietnamiensis）、阴沟肠杆菌（Enterobactercloacae）、路德维希肠杆菌（Enterobacterludwigii）和松江壳聚糖降解菌（Mitsuariachitosanitabida）等不同菌种。【结论】香根草联合固氮菌具有较大的资源多样性，对固氮菌资源的扩展和将来牧草上的应用具有重要意义。

英文摘要：

[ Objective] Vetiver zizanioides is a perennial grass of the Poaceae family, known of its silage, soil and water conservation role. The aim of the study was to collect and identify the resources of the nitrogen-fixing bacteria associated with Vetiver zizanioides. [Methods] Associated nitrogen-fixing bacteria isolated from Vetiver zizanioides were studied by SDS-PAGE wbole-cell protein patterns, insert sequence （IS）-PCR finger printing, utilization of sole carbon sources and 16S rRNA gene sequence analysis. [ Results] Based on the results of finger printing analysis, protein patterns and biological test, isolates were grouped into 6 clusters, except 4 single strains. Phylogenetic analysis of 16S rDNA sequences indicated that isolates belonged to Herbaspirillum frisingense, Enterobacter ludwigii, Pseudacidovorax intermedius, Mitsuaria chitosanitabida, Pseudomonas putida, Pseudomonas fluorescens, Burkholderia viemamiensis and Enterobacter cloacae. [ Conclusion] The nitrogen fixers associated with Vetiver zizanioides showed great diversity and may have a potential application for the grass forage and agriculture.