Bacteria were isolated from the root nodules using common bean as a trap host. Growth and morphological characteristics of the bacterial isolates were described on yeast extract mannitol mineral salts agar and broth media. The results showed that over 67% of the isolates produced extracellular polysaccharide with an entire margin and convex elevation. The others differentiated into cream yellow, cream white and milky white colouration with colony area ranging from 0.8 to 26 mm². The population levels of bacteria nodulating common bean varied in soils and were not affected by the cropping system. However, selected soil parameters greatly influenced the occurrence and distribution of these bacteria. The isolation of indigenous bacteria in all the soils with different cropping systems is an indication that the soils are favourable for nitrogen fixation. Based on the differences in cultural characteristics of the isolates, our data demonstrate the presence of high diversity of bacteria associated with bean nodules.

使用普通豆作为诱捕宿主，从根瘤中分离细菌。在酵母提取物甘露醇矿物盐琼脂和肉汤培养基上描述了细菌分离株的生长和形态特征。结果表明，超过67％的分离物产生具有完整边缘和凸起高度的细胞外多糖。其他的则分为乳黄色，乳白色和乳白色，菌落面积为0.8至26 mm ^2。。结瘤普通豆的细菌种群水平在土壤中各不相同，并且不受种植系统的影响。但是，选定的土壤参数极大地影响了这些细菌的发生和分布。在具有不同种植系统的所有土壤中分离出本地细菌，这表明土壤有利于固氮。基于分离物的文化特征差异，我们的数据表明存在与豆类小结节有关的细菌高度多样性。