EFFECTS OF 2,4-DIHYDROXY-1,4-BENZOXAZIN-3-ONES ON THE ACTIVITY OF PLASMA-MEMBRANE H-ATPASE()

The action of 2,4-dihydroxy-1,4-benzoxazin-3-ones and their correspond ing benzoxazolinone (BOA) derivatives on the activity of plasma membra ne H+-ATPase from roots of Avena sativa and Vicia faba was investigate d. Significant inhibitory effects were found with 2,4-dihydroxy-1,4-be nzoxazin-3-one (DIBOA) and 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-on e in concentrations of 0.25 mM or higher. Benzoxazolinone compounds ca used a weaker inhibition of the enzyme. At low effector concentrations stimulatory effects were observed. The H+-ATPase activity of A. sativ a and V. faba was reduced by DIBOA to the same extent. The allelopathi c effects of DIBOA and BOA on radicle elongation of A. sativa are corr elated with the H+-ATPase activity. Copyright (C) 1997 Elsevier Scienc e Ltd.