RESUMEN
The genotoxic effect of the insecticide malathion and its residues was studiedin Triticum aestivum [wheat] grains and Vicia faba [broad beans] seeds. Wheatgrains and bean seeds were treated with 8, 24, and 40 mg malathion/kg andstored for three and six months. Treatment of the grains [seeds] withmalathion caused a statistically significant decrease in the mitotic index anda significant percentage of chromosome abnormalities after storage for threeand six months. The decrease in the mitotic index indicates inhibition ofcell division. Malathion induced a number of mitotic abnormalities. Thehighest percentage reached 8.73 +/- 0.22 [P <0.01] in root-tip meristems ofVicia faba seeds after treatment of seeds with 40 mg/kg and storage for threemonths. This percentage decreased after storage of the treated seeds for sixmonths, to 3.59 +/- 1.24 [P <0.05]. The percentage of chromosomeabnormalities in the root-tip cells of treated wheat grains was significantafter storage for three and six months. Prolongation of the storage period to six months had no effect on thepercentage of the induced abnormalities. Chromosome stickiness was observedin a high percentage in the root-tip cells of the treated grains [seeds]stored for three and six months. The above-described results indicated thatthe grains [seeds] did not recover after storage for six months. Thenon-recovery of the stored grains [seeds] may be attributed to the permanenteffect of malathion and its residues. The results indicated that malathion iscytotoxic