Evaluation of Genotoxicity Induced by Lanthanum Nitrate in the Root Tip Cells of Vicia faba by Comet Assay

Lanthanum is one of the rare chemicals which are widely used in agriculture in China because of their abilities to increase the yield and to improve quality of crops. But it also has aroused the people's attention to the environmental pollution by the rare-earth elements. To study the genotoxicity of lanthanum nitrate in the root tip cell of Vicia faba, six treated groups with different lanthanum nitrate content(0, 1, 4, 16, 64, 256 mg·L-1 respectively)were designed. Comet assay was used to detect DNA damage of root tip cells of Vicia faba according to the tail length, comet rate, tail moment, olive tail moment. The results showed that the tail length, comet rate, tail moment, olive tail moment of five treated groups were increased significantly with increasing of lanthanum nitrate concentration compared with the control group. It mean that DNA of root tip cell of Vicia faba can be damaged by lanthanum nitrate. In 1～64 mg·L-1 the damage extent was enhanced with increasing of lanthanum nitrate concentration. Genetic material was serious damaged in the concentration of 256 mg·L-1. On the contrary, the tail length, comet rate and tail moment were descent. It suggests that lanthanum nitrate has genotoxicity and cytotoxicity to root tip cells of Vicia faba.