Studies on the induction of wheat cytochrome P450 by mefenpyr-diethyl and P450-CO difference spectrum

After treatment of R-6# wheat (a tolerant wheat) with 50?mol/ L mefenpyr-diethyl, its cytochrome P450 content was up to 108.18 pmol/mg protein, which is 1.67 times as the control's. 100?mol/ L mefenpyr-diethyl raised the cytochrome P450 content of S-18# wheat (a sensitive wheat) by 86%, up to the maximum 80.97 pmol/mg protein, compared to that of the control. The results indicated that mefenpyr-diethyl could induce cytochrome P450 in two of the wheat cultivars, but R-6# is more susceptible to induction than S-18#, which is in agreement with the results obtained by herbicide treatment. After crude microsomal preparation stored at room temperature (20?1)? for 200 minutes, the cytochrome P450 was entirely transformed into the inactive form, cytochrome P420.