Abstract
Contents of pretilachlor [2-chloro-2′, 6′-diethy1-N-(2-propoxyethyl)-acetanilide], fenclorim [4, 6-dichlor-2-phenylpyrimidine] and metabolites of the two chemicals in rice (Oryza sativa L. cv. Nipponbare) and early watergrass (Echinochloa oryzicola Vasing.) seedlings treated with pretilachlor alone or a combination of pretilachlor and fenclorim were examined in relation to selectivity and safener action. The contents of pretilachlor and a metabolite of fenclorim (GS-fenclorim) were lower in rice than in early watergrass seedlings, but the contents of fenclorim and metabolites of pretilachlor were higher in rice than in the watergrass. The results illustrated that selectivity of pretilachlor between rice and early watergrass might be strongly related to the content of pretilachlor and the detoxicative metabolisms, and the safening effect of fenclorim might also be related to the content of fenclorim and its metabolite in the two plants.
