Genotoxicity studies on the insecticide Dursban in root meristem cells of Crepis capillaris L

Dursban, an insecticide of the organophosphorous group of pesticides, was studied for genotoxicity in plant cells (Crepis capillaris L.) with regard to its ability to induce structural chromosomal aberrations and micronuclei. It was observed that at concentrations comparable to those applied in agricultural practice, Dursban did not induce chromosomal aberrations as estimated by metaphase and anaphase analyses. In the latter case, lagging chromosomes were observed. The frequency of micronuclei (MN) for the Dursban-treated group was statistically significantly increased in comparison with the control: this effect was observed at all concentrations tested. To elucidate the mechanism of MN formation, the micronucleus/macronucleus size ratio was determined. Micronuclei induced by colchicine and γ-rays were used as controls. The size of micronuclei induced by Dursban is similar to that of micronuclei induced by colchicine and significantly larger than that induced by γ-rays. It was concluded that the formation of micronuclei after Dursban treatment of plant cells was due to partial spindle disturbances, leading to errors in anaphase distribution of the chromosomes, as a result of which some chromosomes appear as lagging ones. (author)