The Effects of Lead and Cadmium on Cell Division and Chromosomal Structure in Allium cepa Test System In Vivo

The present work focuses on the study of the potential mito-inhibiting and genotoxic effect of lead and cadmium in the root meristem of Allium cepa L. in vivo. A cytotoxic effect of lead and cadmium was registered, as evidenced by the lower mitotic index values in all test concentrations compared to the control. The analysis of the microscopic preparations for the experimental variants of the two heavy metals showed a significant genotoxic effect. All analyzed samples of lead and cadmium demonstrate an increased frequency of chromosomal aberrations compared to the control, as a positive dependence was established between the frequencies reported and the concentration of the studied metals. Lead and cadmium solutions cause a wide range of chromosomal aberrations, varying with the dose of the metal. The most common observed disorders are: acentric fragments, lagging and “vagrant” chromosomes, micronuclei, chromosome bridges, and asynchronous mitosis, demonstrating the genotoxic potential of the studied heavy metals. For both metals a maximum frequency of aberrations for the concentration limit is established. By comparing the two heavy metals, it has been found that lead has a greater cytostatic potential than cadmium by more effectively inhibiting cell division. The results obtained regarding the frequency of chromosomal aberrations show a higher genotoxic effect of cadmium compared to lead.