中文摘要：

对分离自西北地区6个矿区采样点的68株天蓝苜蓿根瘤菌进行了生理生化特性和16S rDNA PCR-RFLP分析。唯一碳源利用结果表明：供试菌株均能利用丁二酸钠等7种碳源,均不能利用马尿酸钠等4种碳源。在苯酚作为唯一碳源的培养基上生长试验表明：所有菌株可以在400 mg/L的苯酚培养基上生长;5株菌可以在700 mg/L浓度下生长;所有菌株都不能在800 mg/L浓度以上的苯酚培养基上生长。重金属耐受性结果表明：供试菌株对重金属有不同程度耐受性,筛选出1株具有优良重金属耐受性的菌株CCNWGS0037。16S rDNA PCR-RFLP分析结果表明：所有菌株可以分为3种类型,全序列测定结果分析表明分别属于中华根瘤菌属（Sinorhizobi-um）、根瘤菌属（Rhizobium）和土壤杆菌属（Agrobacterium）。综合分析,矿区天蓝苜蓿根瘤菌多样性比较单一。

英文摘要：

68 rhizobia strains isolated from Medicago lupulina in mining regions of Northwest China were analyzed to study their physiological and biochemical characters and 16S rDNA PCR-RFLP,The only carbon source use results show that all the tested strains can use 7 kinds of carbon sources including sodium succinate,but cannot use 4 kinds of carbon sources including sodium hippurate.When the phenol is used as the only carbon source,all the tested strains can grow under 400 mg/L,but cann＇t grow under 800 mg/L or more than that,5 strains can grow under 700 mg/L.The tested strains have different resistibility to heavy metal.One isolate,CCNWGS0037,with the best resistibility to heavy metal is obtained. All the 16S rDNA fingerprints are divided into three types,and the full-length sequences and PCR-RFLP of 16S rDNA show that the tested strains belong to Sinorhizobium and Rhizobium and Agrobacterium respectively.From this study,it can be concluded that the diversity of the tested strains is poor.