in Sorghum (Sorghum bicolor)l

The herbicide safener OTC (L-2- oxothiazolidine-4-carboxylic acid) increased the amount of reduced thiol compounds in sorghum (Sorghum bicolor (L.) Moench. 'DK 427') seedlings. When seedlings were grown in liquid culture medium containing 35S-OTC, the compound was metabolized to radiolabeled cysteine and glutathione. The addition of tridiphane (2-(3,5- dichlorophenyl)-2-(2,2,2-trichloroethyl)oxirane) increased conversion of 35S-OTC to cysteine and resulted in the formation of one additional 35S-labeled compound. When 35S-glutathione was injected into germinating seeds it was converted to 35S-cysteine and both thiols were subse- quently found in roots and shoots. Seeds injected with 35S-OTC both translocated the compound to developing roots and shoots and metabolized 35S-OTC to cysteine and glutathione. Excised roots and shoots also metabo- lized 35S-OTC to the thiols. In an in vitro assay the enzyme 5-oxoprolinase converted OTC to cysteine. No- menclature: Sorghum, Sorghum bicolor (L.) Moench. 'DK 427'. Additional index words. Antagonist, herbicide antidote, glutathione, cysteine, 5-oxoprolinase, 5-oxoproline.