Abstract: DNA damage of Vicia faba root tip cells caused by phenanthrene was investigated using the comet assay. The resulting comet image was analyzed using Software Komet Version 6.0. Olive tail moment (OTM) was found to be the most preferable parameter to evaluate DNA damages. As observed in the cellular comet assay, the DNA damage of Vicia faba root tip cells was aggravated with rising phenanthrene concentrations (0-0.6 mg•L^-1) in solution. With a high concentration (0.6 mg•L^-1), the OTM increased by 132.63% as compared with the control. An obvious phenanthrene dose-dependent relationship was observed for DNA damage. However, DNA damage by 0.1 mg•L^-1 phenanthrene was time-dependent, aggravating with the passing time in the first 12 h and then mitigating in the second 12 h. In order to determine pathways of phenanthrene-caused DNA damage, direct effect of phenanthrene on Vicia faba root tip cell DNA was assessed with the acellular comet assay. It was found that phenanthrene at 0.05 mg•L^-1 caused significant damage (OTM 22.27±0.42) to Vicia faba root tip cell DNA and the damage aggravated with the increasing phenanthrene concentration (0-0.6 mg•L^-1).

Key words: phenanthrene, DNA damage, comet assay, Vicia faba