DIAZOSULFONATES AS PROTECTANTS AGAINST ATRAZINE TOXICITY TO SOYBEANS

Abstract

A series of benzenediazosul fonates were synthesized and evaluated as potential antidotes to residual atrazine toxicity to soybeans [ Glycine max (L.) Merr.]. Greenhouse experiments were conducted using soil incorporated or seed coated sodium p -(dimethylamino) benzenediazosul fonate (dexon), sodium p -methylbenzenediazosulfonate (MBDS), sodium p -chloro-benzenediazosulfonate (CBDS), and sodium benzenediazosulfonate (BDS). A concentration of 0.2 ppm (w/w) of atrazine in the soil gave an average soybean dry weight of 16% of control after 26 days. Incorporation of dexon from 25 to 400 ppm (w/w) in soil containing 0.2 ppm atrazine gave proportionate increases in plant dry weight, being 76% of control at 400 ppm. After 66 days dexon completely prevented the reduction in soybean leaf and stem dry weight caused by atrazine, with similar protection for roots. Soil incorporated MBDS also protected soybeans, however, CBDS or BDS gave no protection against atrazine toxicity. Seed coating of the diazosulfonates did not provide protection, but a seed coating of 0.1% BDS alone gave a 27% increase in dry weight over control after 26 days.