| Abstract
| - Plasma membrane lipid composition of herbicide-resistant (R) and-susceptible (S) wild oat biotypeswas analyzed to determine the basis for the differential effect ofdiclofop on the transmembraneelectrogenic potential between the two biotypes and reduced herbicideuptake into protoplasts ofthe R biotype. In addition, lipoxygenase (LOX) activity wasexamined in herbicide-treated anduntreated R and S plants to determine its involvement in herbicideaction and resistance. Overall,no significant differences in lipid composition were found between thetwo biotypes. Glycolipidsrepresented 41 and 36%, phospholipids 29 and 37%, and free sterols 30and 27% of the total plasmamembrane lipid in the R and S biotypes, respectively. Nodifferences in LOX activity were observedbetween the herbicide-treated and untreated wild oat biotypes. Itwas concluded that differencesin membrane transport of diclofop and its effect on plasma membranepotential in the R and Sbiotypes are not related to differences in membrane lipid compositionor to differential effects ofherbicides on LOX activity in the two biotypes. Keywords: Wild oat; herbicide resistance; lipid composition; lipoxygenase;ACCase inhibitors
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