| Pb2+ is one of the major elements in the environment. In order to investigate the physiological characteristics and geno-toxicity effects of foxtail millet [Setaria italica（L.）Beauv] under different Pb2+ stress, four genotypes of foxtail millet（Zhaogu, Huangmi, An06, D2-8） from Shanxi, China were cultivated for 30 days in a pot filled with soil of different mass concentrations 0 mg·kg-1, 50 mg·kg-1, 100 mg·kg-1, 200 mg·kg-1, 400 mg·kg-1. Pb2+ stress effects on DNA damage of genome on foxtail millet were studied using random amplified polymorphic DNA（RAPD）, and the contents of soluble sugar, proline and MDA were tested. The results showed that the contents of soluble sugar were decreased in the range of 31.45%~49.11% compared to the control group, with the increasing of Pb2+ concentration. Also, the contents of proline synthesis were enhanced at low concentrations（less than 100 mg·kg-1）, but inhibited at high concentrations（more than 200 mg·kg-1）. The contents of MDA of four genotypes foxtail millet were significantly increased compared with the control group. The changes of random amplified polymorphic DNA profiles of four genotypes foxtail millet following Pb2+ treatment included appearance of new bands and loss of normal bands and variation of fluorescence intensity compared to the plantlet without treatment, suggesting that Pb2+ significantly affected the stability of the genomic template DNA in cells of millet seedlings. Additionally, the effect of DNA polymorphism changes was dose-dependent with the Pb2+ concentration. The physiological and genetic damage under Pb2+ stress had significant differences in the different genotypes millet. The change of DNA polymorphism using RAPD technique could be used as the biomarker to detect genotoxic effects of Pb2+. |
