Effect of (R)-(+)- and (S)-(-)-Quizalofop-ethyl on Lipid Metabolism in Excised Corn Stem-base Meristems

Mechanism of Action of the Herbicide Quizalofopethyl (Part 2)

Abstract

Effects of the selective postemergence herbicide quizalofop-ethyl on lipid biosynthesis were studied in excised stem-base segments from corn seedlings grown in a greenhouse after foliarapplication. Incorporation of ¹⁴C-acetate into total lipid of the segments was inhibited by the (R)-(+)-enantiomer, while the (S)-(-)-enantiomer was inactive. TLC analysis of the lipid extract showed quantitative alteration especially in fatty acid and phospholipid. Comparison of HPLC profiles of phenacyl esters of the fatty acid fraction and their ¹⁴C-determination with those of the control revealed a reduction in palmitic acid and linoleic acid content. The results indicated that fatty acid biosynthesis is a possible primary site of action of quizalofopethyl.