Abstract
The growths of water-cultured rice plants to which silica was supplied at different growth stages (Fig. 1), were observed, and the following results were obtained : 1) Heights of the plants grown with nutrient solutions lacking in silica throughout the whole period together with those grown with silica for a short part of the period were all lower than those of the plants supplying silica for longer periods. 2) There were found no differences in the number of stem and leaf due to the treatment, but it was evidently recognized that the plants supplied with silica only for a shorter period produced many small tillers and many of those withered quickly. 3) SiO2 contents and weights of dry matter in each organ of the plants were larger by the long period silica treatment. According to the facts above mentioned, it may be concluded that silicon is an essential element for rice plant and its normal growth is attained by supplying silica for a period as long as possible.
