The Diphenyl-Ether Herbicide Oxyfluorfen: A Potent Inducer of Lipid Peroxidation in Higher Plants

Measurements of ethane and ethylene as indices of in vivo lipid peroxidation and of chemically- induced stress, respectively, were done on mustard seedlings (Sinapis alba), treated with oxyfluorfen[2-chloro-1-(3-ethoxy-4-nitrophenoxy)-4-(trifluoromethyl)benzene]. When seedlings were exposed to low light intensity of 14W/m2, only stress-ethylene production but not per- oxidative ethane evolution was significantly higher over 10 days in herbicide-treated seedlings than in the untreated control. Exposure to high light intensity of 390 W/m2 did not increase stress-ethylene production in oxyfluorfen-treated plants after 24 h. Lipid peroxidation, however, measured as ethane evolution, was substantially higher after 24 h in herbicide-treated plants, exposed to high light intensity, than in the control, and peroxidation was directly related to strong oxidation of antioxidants and to severe membrane damage.