Protective effect of two synthetic compounds against chlorsulfuron injury in maize ( Zea mays L.)

Abstract

Two new synthetic compounds — urea (B-3) and thiourea (B-6) derivatives of 4-methylpiperazinyl — were investigated as possible antidotes for chlorsulfuron in maize. It was established that the thiourea derivative was a more effective herbicide protector than the urea derivative. The shoot length of maize plants treated with 10−5M chlorsulfuron was inhibited 60% compared to the untreated plants, whereas pretreatment with 5×10−4M B-6 reduced this inhibition to 23%. Moreover, the decrease of 53% in shoot fresh weight caused by herbicide applied alone was countered almost completely by B-6 with only an 11% loss in fresh weight observed. The results of this investigation show that the urea derivative (B-3) appeared to be ineffective in antidoting the injurious effect of chlorsulfuron. Decreases in root length and fresh weight were also offset by B-6. The more favourable protective activity of the thioureido group in B-6 could be due to the formation of an isomer with isothiourea structure, having a sulphydryl group. Treatments with herbicide and B-3 / B-6 alone or in combination had no significant effect on the parameters of the antioxidative defence system tested.