Abstract: Under the treatment of heavy metal ions Pb2+, Cd2+ and Hg2+, the interval of mitotic stage was shortened, and the time of interphase prolonged so that the cell cycle was prolonged in the root-tip cells of broadbean (Vicia faba L. ). With the increase of concentrations of Pb2+, Cd2+ and Zn2+ below 1.0, 0.01 and 10 ppm respectively, the mitosis index (IM) rose in root-tip cells, but IM decreased when the root-tips were treated with the some heavy metal ions above the above-mentioned respective concentrations. IM was inhibited in Hg2+ of any concentrations. Within the concentration of Pb2+, Cd2+, Hg2+ and Zn2+ below 1.0, 0. 50, 5.0, 100.0 ppm respectively, the frequency of micronucleus (MCNF) rose as the concentrations were increased, and lowered as the respective concentrations exceeded those stated above. Similar changes occurred in the frequency of chromosomal aberrations (CAF) when the concentration of Pb2+, Cd2+, Hg2+, Zn2+ were below or above 5.0, 5.0, 0.50, 100.0 ppm respectively. Mn2+ had no significant effects to them. By data processing with the method of gray system control and computer aided drawing to IM, MCNF and CAF, it was shown that the three parameters varied tremendously in different dose-effect ranges. All of which suggested that in order to obtain a reliable results in the environmental monitoring and hazardous material detection, genetoxicity inspection should be carried out under the optimal condition when (1) the concentration of the heavy metal to be detected does not seriously inhibit mitosis and (2) CAF and MCNF is in positive correlation.

Key words: Heavy metals, Vicia-micronucleus test, Cell cycle, Cytogenetical toxicity, Chromosomal aberrations