On the ash figures of leaves of the rice plants transplanted from the different kinds of nursery beds and their susceptibilities to the blast disease

Abstract

In Japan the method of cultivation of the rice plant is quite different from that of other cereals and the proper preparation of the land for the seedlings later to be transplanted, is most important in order to obtain strong and healthy plants. For this purpose the nursery-beds with or without covering water are most commonly used. Among the grown rice plants transplanted from these nursery-beds in their seedling stage, there seems to exist a difference of susceptibility to the blast disease. It is clear that the plants originated from humid soil are more resistant than those from arid soil. In the present paper, the writer has discussed the results of comparison of the ash figures in leaves of rice plants transplanted from these two nursery-beds. The number of silicated epidermal cells per unit area of leaf, especially of the bulliform cells, is larger in plants transplanted from the former than in those transplanted from the latter. It seems to be very interesting that the number of silicated cells in the bulliform cells, which are more easily penetrated by the causal fungus (Piricularia Oryzae B. et C.) than the long and short cells, varies in accordance with such different conditions in the seedling stage.