Metabolic Fate of 3,4-Dichloropropionanilide in Plants: The Metabolism of the Propionic Acid Moiety

3,4-Dichloropropionanilide-(14)C (propanil) labeled in either the C-1 or C-3 carbon atoms of the propionic acid moiety was applied to the roots of pea (Pisum sativum L.) and rice (Oryza sativa L.) plants in nutrient solution (0.1 mm-0.28 mm). Radioactivity was detected throughout the treated plants, but the greatest labeling was found in the roots. None of the products that contained aniline were radioactive, suggesting that the plants split the propionic acid moiety from propanil. The fate of the propionate moiety of propanil was determined by recovery of (14)CO(2) from plants exposed to propanil-(14)C. The time-course of the (14)CO(2) production demonstrated that the intact propionic acid was cleaved from the propanil and subsequently catabolized by the beta-oxidation catabolic sequence. The appearance of radioactivity in the shoots was attributed to the incorporation of products of propionate metabolism. Both the susceptible pea plants and the tolerant rice plants converted a high percentage of the administered propanil-(14)C to (14)CO(2).