Abstract
Relationship between structure and physiological activity of some carbostyril compounds was investigated. It revealed the followings; Though carbostyril itself has no physiological activity, 3-hydroxycarbostyril derivatives all have an antimicrobial activity, and methylation or carboxymethylation of the hydroxyl group causes loss of the activity. While, these 3-methoxy- or 3-carboxymethyleneoxy-carbostyril compounds display a remarkable promoting effect on the root growth of young plants, and phenyl group substituted at 4-position further enhances such activity. On the other hand, methylation of _??_NH group in carbostyril compounds not only lowers the antimicrobial activity, but almost completely abolishes the plant growth activity.
Mode of action of carbostyril compounds on plant growth resembled that of 2, 4, 6-trichlorophenoxyacetic acid, an antiauxin, and indole-3-acetic acid-induced lamina inclination in rice explants was inhibited by carbostyril compounds.
