Abstract: By the methods of 16S rDNA cloning, amplified ribosomal DNA restriction analysis (ARDRA), and sequence homology comparison, this paper studied the genetic diversity of rhizobia isolated from the nodules of leguminous plants in Lanping lead-zinc mining tailings of Yunnan. Sequence analysis revealed that among the 49 positive clones in the 16S rDNA library, 3 operational taxonomic units (OTUs) were identified, based on the similarity of 40% ARDRA banding profiles at the sampling sites where the nitrogen, Pb²⁺, Zn²⁺ contents were different, suggesting that the genetic diversity and distribution of rhizobia could be related to the soil nitrogen, Pb²⁺,and Zn²⁺ contents. Diverse phyla of the representative strains in the 16S rDNA library were belonged to the three phylogenetic branches of Rhizobium sp., Sinorhizobium sp., and Bradyrhizobium sp. The results suggested that there was a higher genetic diversity of rhizobia isolated from the nodules of leguminous plants in the Lanping lead-zinc mine tailings of Yunna.

Key words: Flaveria bidentis, net photosynthetic rate, chlorophyll fluorescence, growth characteristics, relative competitive index.