Abstract
This investigation was conducted on rice seedlings to elucidate the plant growth-regulating properties of 3-hydroxy-5-methyl isoxazole which is an effective fungicide against the damping-off organism of rice seedlings. The results obtained are summarized as follows: 1) The promotion of root growth by 3-hydroxy-5-methyl isoxazole was assumed to be mediated by its metabolite (N-β-glucoside) in plants. 2) The formation and development of lateral roots and root hairs were accelerated in the early seedling stage. The root growth was vigorously promoted by 3-hydroxy-5-methyl isoxazole in the later seedling stage. 3) The rooting ability and root activity (oxidizing or reducing activity of roots) were enhanced by 3-hydroxy-5-methyl isoxazole.
