Cytological effects of pesticides. XVI Effect of the insecticide rotenone on root-mitosis of Vicia faba.

Abstract

The effect of the insecticide “rotenone” has been studied on mitosis in the roots of Vicia faba (V. Giza 1). Two types of treatment were conducted: seed soaking and exposure of the roots. Examination of the roots was done in permanent root-tip squash preparations stained by the Feulgen technique. Three roots were examined from each of the 3 replicates and 2000 cells were scored from each of the 9 roots.Root-treatment for 4 hours with saturated aqueous solution of rotenone in-duced a statistically significant percentage of abnormal cells which increased by improving the solubility of the insecticide by dissolving it in a Tween: water mixture (1: 99). The types of abnormalities induced included: disturbed meta- and ana phases (where, the chromosomes spread irregularly over the cell) in a high per-centage, chromosome stickiness, lagging chromosomes and ana-telophase bridges. Cytomixis was observed in some roots and tetraploid cells were seen in a few roots.The effect of rotenone on root-mitosis simulates that of colchicine in the type of the abnormal meta- and anaphases (with X-shaped chromosomes) and the induction of tetraploid cells. Rotenone, on the other hand, did not affect the mitotic index nor caused accumulation of the metaphases.