Abstract
The metabolic fate of the herbicide naproanilide, 2-(2-naphthoxy) propionanilide, was investigated in rice plants (Oryza sativa L.) and Sagittaria pygmaea MIQ. 14C-Naproanilide, uniformly labelled at the naphthalene-ring, was metabolized to phytotoxic 2-(2-naphthoxy)-propionic acid (NOP) in both plant species. In rice plants, NOP subsequently underwent hydroxylation and then rapid conjugation with glucose; considerable radioactivity was found in the water-soluble compounds and the aqueous methanol-insoluble residue. Phytotoxic methyl 2-(2-naphthoxy) propionate (NOPM) was produced only in small amounts. In S. pygmaea, the rates of NOP and NOPM were significantly greater than in rice plants. 2-Naphthol and 2-hydroxy-1, 4-naphthoquinone were also produced but only in small amounts. The difference in the metabolic products of naproanilide between the two plant species showed a possible mechanism of their herbicidal selectivity.
