Abstract
This investigation was conducted on rice seedlings to elucidate the plant growth-regulating properties of nicotinamide which was isolated from rice hulls. The results obtained were summarized as follows: 1. Effects of nicotinamide on growth of rice seedlings, ability of preventing chlorophyll degradation in leaf tissue of rice plant and germination ability were greater than those of nicotinic acid. 2. The root growth of rice was promoted by seed soaking treatment with nicotinamide. 3. The top and root growth of rice were accelerated by pre-transplanting root soaking treatment with nicotinamide, and the root fresh weight was increased remarkably. 4. Soil treatment with nicotinamide and nicotinamide with hydroxy isoxazole immediately after sowing of rice seeds in the seedling beds markedly enhanced the rooting ability and root activity (oxidizing or reducing activity of roots) and the increasing rates of geotropic curvature response of rice seedlings. 5. The growth promoting activity with nicotinamide was particularly shown after the fifth leaf position of rice.
