新疆乌恰县豆科植物根瘤菌数值分类研究

新疆乌恰县具有独特的地理环境与气候条件,蕴藏着丰富的结瘤豆科植物资源.本研究从乌恰县豆科植物根瘤中分离到40株根瘤菌,并进行唯一碳源利用、唯一氮源利用、对抗生素和染料的抗性、耐盐性、初始pH生长、生长温度范围及石蕊牛奶反应、氧化酶、过氧化氢酶、脲酶共118项生理生化性状测定.结果表明:乌恰县豆科植物根瘤菌在碳氮源利用、抗生素敏感性、对染料抗性程度等方面存在着差异.供试根瘤菌能耐受较低温度,并具有较强的耐盐、碱能力,均能在pH 6~12的YMA培养基上生长,有60%的菌株能耐受0.86mol/L的NaCl.数值分类结果表明,在84.2%的相似水平上40株供试菌株构成了4个新的表观群.第Ⅰ、Ⅱ、Ⅲ和Ⅳ类群分别有8、9、3和3株菌,中心菌株分别为NWWQ73-2、NWWQ13-1、NWWQ1-2、NWWQ6-2.此外,乌恰县豆科植物根瘤菌与模式菌株的相似性较低,它们所形成的4个独立群可能有新种存在.

Numerical Classification of Rhizobia in Leguminous Plants of Wuqia County, Xinjiang

Wuqia County of Xinjiang has abundant leguminous plants capable of forming nitrogen-fixing root nodules because of its unique geographical and climatic conditions. This study isolated forty strains of rhizobia and conducted the tests about their 118 physiological and biochemical parameters concerned with the uses of single carbon and nitrogen sources, antibiotic and chemical dye resistance, growth at the initial pH,temperature range of growth, oxidase, superoxidase and urease, and litmus and milk responses. It was shown that the rhizobia in Wuqia County of Xinjiang differed in carbon and nitrogen uses,antibiotic sensitivity, and chemical dye resistance. The tested rhizobia could tolerate relatively low temperature, had strong salt-and alkaline-tolerating capacities and was capable of growing on Mannitol-yeast extract medium (YEM) with pH at within 6～12,and sixty percent of them could tolerate 0.86 mol/L NaC1. Numerical classification revealed that the tested forty strains of rhizobia formed four new phenotypic clusters, with their similarity at 84. 2%. Clusters Ⅰ, Ⅱ, Ⅲ and Ⅳ separately contained 8,9,3 and 3 strains and their central strains were separately NWWQ73-2,NWWQ13-1, NWWQ1-2 and NWWQ6-2. In addition,the rhizobia in the leguminous plants of Wuqia County were similar to the type strains and the new clusters that they formed probably contained new species.