Effect of Long-Term Stress of High Pb/Zn Levels on Genomic Variation of Sedum alfredii Hance

Abstract

In this study, the heavy metal contents were detected in plants of Sedum alfredii and soils from Pb/Zn mined area and non-mined area, and a dendrogram was generated by using RAPD methods based on the hyperaccumulating ecotype (HE), the non-hyperaccumulating ecotype (NHE) and other species of Sedum. The results showed that the available Pb of the Pb/Zn mined soil was 77-fold higher, and available Zn and Cd were 10-fold and 16-fold higher in the mined soil than in the non-mined soil, respectively. The dendrogram showed that the HE S. alfredii was the nearest relative to NHE S. alfredii. However, genomic variation of two ecotypes was still notable, indicating that heavy metal stress had great impacts on the genetic diversity and plant evolution, and HE may be a mutant from the NHE. Ten RAPD bands were observed only in the HE as compared with other species of Sedum. The character of Zn/Cd hyperaccumulation in HE appeared to be related to SH-containing compounds and resist osmotic stress, and also many unknown genes.