Abstract: Nine Rhizobium strains,isolated from eight species of tropical and sub-tropical legumes,were examined for plasmid content.Each of the fast-growing strain tested contained 1~6 plasmids wjth molecular weight from 32 kb to 870 kb.At least one of these plasmids was small (molecular weight was less than 100 kb),and three strainscontained only one small plasmid (molecular weight was less than 50kb).The plasmid profiles of Rhizobia from each species of the tropical and subtropical legumes were di-verse.

Key words: Tropical and subtropical legume, Rhizobium, Megaplasmid

摘要： 从8种热带、亚热带豆科植物中分离出9种快生型根瘤菌,用双梳子胶内裂解法检测其中的质粒分布情况。质粒数从1到6个不等,大小从32 kb到870 kb,其中至少有一个分子量小于100 kb的质粒。从不同种属的豆科植物中分离出的根瘤菌,其质粒的数量及分子量各不相同。

关键词: 热带、亚热带豆科植物, 根瘤菌, 大质粒