Response of Soybean Mitochondria to Substituted Dinitroaniline Herbicides

Abstract

Effects of the inhibitors DNP (2,4-dinitrophenol) and oligomycin, and the substituted dinitroaniline herbicides, trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine), nitralin [4-(methylsulfonyl)-2,6-dinitro-N,N-dipropylaniline], and oryzalin (3,5-dinitro-N4,N4-dipropylsulfanilamide) on mitochondrial tractions isolated from soybean (Glycine maxL. ‘Lee’) hypocotyls were examined. Oryzalin and nitralin uncoupled succinate oxidation at the ADP-limited state 4, as did DNP. Trifluralin caused no effect on the second state 4, but inhibited oxidative phosphorylation in a manner similar to the effect of the energy-transfer inhibitor oligomycin. Studies of the interaction of these inhibitors indicate that the sites of action for these herbicides may be different.