Abstract
Phytotoxic activity of the thiocarbamate herbicide dimepiperate (S-1-methyl-1-phenylethyl piperidine-1-carbothioate) and its effect on plant metabolism were investigated. The chemical was highly selective against tested monocotyledonous plants. Rice and corn showed strong tolerance, while barnyardgrass and crabgrass were susceptible to the herbicide. Dicotyledonous plants were tolerant.
Dimepiperate (10-5M) reduced 14C-acetate incorporation into lipid fraction in leaf disks of barnyardgrass more than 30% at 60min after incubation. Lipid synthesis inhibitor, cerulenin, caused the same level of reduction of the acetate incorporation at 10-5M, and this incorporation was inhibited even with 10-6M dimepiperate.
Reduction of 14C-leucine and 14C-glucose incorporation into protein and cell wall fraction, respectively, were detected at 120min with 10-5M. None of RNA and DNA synthesis, photosynthesis or respiration was affected by the herbicide. The results suggest that the primary site of action of dimepiperate is in the lipid synthesis pathway.
