CORRELATION OF PROPANIL HYDROLYZING ENZYME-ACTIVITY WITH LEAF MORPHOLOGY IN WILD RICES OF GENOME CCDD

The propanil hydrolyzing enzyme, aryl acylamidase I (AAI) (arylacylamine amidohydrolase, EC 3.5.1.13), was highly correlated (r = -0.83) with leaf width in three species of genus Oryza with genome CCDD. The specific activity of AAI was lower in the leaves of wide-leafed plants and this was well-reflected in propanil phytotoxicity in those plants. There were no significant differences between conjugation of 3,4-dichloroaniline or the presence of AAI inhibitors in the crude enzyme solutions from the narrow-leafed and wide-leafed strains. The same relationship between AAI activity and leaf width was observed in interspecific F1 hybrids involving genome CCDD. In those F1 hybrids the wide- and narrow-leafed strains showed comparable AAI activity per leaf of equal length. It was concluded that the concentration of the enzyme in the CCDD plants was diluted by plant bulk in the wide-leafed strains and the correlation appeared to be the indirect effect of genes altering plant morphology, especially leaf area. The significance of the correlations is discussed in relation to propanil resistance and plant phylogenetics. © 1991.