A comparative study of the cytogenetic effects of the insecticides heptachlor, malathion, and methyl parathion in Vicia faba

In order to determine the potential cytogenetic effects of Heptachlor, Malathion and Methyl Parathion, meristems of broad bean root tips were treated with severa1 concentrations o£ these insecticides for different periods of treatment and recovery. Heptachlor and Malathion induced chromosomal alterations in anaphase cells as fragments and bridges, chromosomes with inactivated centromeres and isochroinosomes, and as micronuclei in interphase cells. Multipolar anaphases also appeared when the mitotic spindle was damaged. Heptachlor induced pycnosis but Malathion did not. Chromosomal aberrations caused by Methyl Parathion were observed in cells only during metaphase, since a strong c-mitotic effect was induced mostly in the form of fragments. Longer recovery periods (42 and 44 h) revealed tetraploid and pycnotic cells. Only in the case of Malation was there an increase in chromosome alterations with higher concentrations. However, no such dose response relationship was observed for micronuclei frequency.