Mode of Action Investigations with the Herbicides HOE-39866 and SC-0224

Abstract

In laboratory experiments, the effects of the herbicides HOE-39866 [ammonium (3-amino-3-carboxypropyl)-methylphosphinate] and SC-0224 (trimethylsulfonium carboxymethylaminomethylphosphonate) on the incorporation of NaH14CO3, [14C]-leucine, [14C]-uracil, and [14C]-acetate into enzymatically isolated soybean [Glycine max(L.) Merr. ‘Essex’] cells were evaluated to assess the activity of these herbicides on CO2fixation, protein, ribonucleic acid (RNA), and lipid syntheses. At low concentrations neither compound exhibited rapid or distinct inhibitions of any process as might be expected in the case of inhibition of a primary target site. Photosynthesis was the process least affected. At equimolar concentrations, protein and RNA syntheses were more sensitive to HOE-39866 than to SC-0224 while the reverse occurred in lipid synthesis. Protein synthesis appears to be a possible target site that may be involved in the herbicidal action of these two compounds.