COMPARATIVE CYTOLOGICAL EFFECTS OF THE PESTICIDES MENAZON, METROBROMURON AND TETRACHLOROISOPHTHALONITRILE INHORDEUMANDTRADESCANTIA

The biological effects of an s-triazine insecticide: menazon (MEN), a substituted urea herbicide: metobromuron (PAT) and an aromatic hydrocarbon fungicide: tetrachloroisophthalonitrile (DAC) were compared with those of ethylmethanesulfonate (EMS) and X-irradiation. Seeds of barley (Hordeum vulgare L.) were soaked in solutions of the chemicals before determining percentage germination, seedling height and frequency of chromosomal aberrations. In addition, somatic mutations in inflorescences of Tradescantia clone 02 treated with solutions of the chemicals were counted. X-rays induced a high frequency of chromosome breaks but had no effect on any other character. In contrast, EMS had a pronounced effect on all the characters studied. Only one pesticide, PAT, had significant effects. The herbicide reduced germination percentage, seedling height and the mitotic index in barley. It is concluded that EMS and X-rays have a cytogenetic action in the treated cells, whereas PAT induced a severe physiological effect.