| dc.description.abstract | In the present study, the cytotoxic effects of different concentrations of lead (Pb) and mercury (Hg) ions on Cicer arietinum L. root tip cells were investigated. For this aim, we used the aermination percentage, root length, weight gain, mitotic index (MI), the frequency of micronucleus (MN) and chromosomal aberrations (CAs) as indicators of cytotoxicity, and correlated these data with statistical parameters. Additionally to the cytogenetic analysis, lipid peroxidation and DNA analyses were performed in root tip meristems of C. arietinum treated with Hg and Pb. The seeds were divided into 5 groups as control, Hg and Pb treatment groups. They were treated with 10 and 50 ppm doses of Hg and Pb during 7 consecutive days. The initial and final weights of all the seeds were measured by sensitive balance to determine the effects of Pb and Hg on the weight gain. As a result, there was a significant alteration in germination percentage, root length, weight gain, MI, MN and CAs frequency depending on treatment dose in the seeds exposed to Hg and Pb when compared with the controls. Heavy metal exposure significantly reduced the germination percentage, root lenght and weight gain in all the treatment groups. But, it caused an increase in the MN and CAs formation. Pb and Hg metals caused various types of CAs at a rate which increased systematically with increased levels of Pb and Hg. It was also found that Pb and Hg metals have a mitodepressive action on mitosis, and the MI was decreased depending on the dose of Pb and Hg applied. Besides, 10 and 50 ppm concentrations of Pb and Hg significantly enhanced the lipid peroxidation and caused an increase in malondialdehyde (MDA) levels at both doses. The investigated parameters (except MDA, MN and CAs frequency) were higher in the seeds exposed to Pb than those treated with Hg. In other words, Hg had much more toxic effect on plant tissues than Pb. Moreover, it was observed that the yields of DNA in the seeds treated with Pb and Hg were lower than in the controls. Hence, DNA yields exposed to Pb and Hg were run ahead on agarose gel according to the control group. The results clearly indicate that Hg and Pb have important cytotoxic effects on the root tip cells, and C arietinum seeds are very sensitive and useful as biomarker for monitoring of these effects. | en_US |
