Abstract
In this communication we dealt with the conidial germination and hyphal invasion of Helminthosporium oryzae on or into the leaves of rice plants raised in sand culture with different nutrient solutions.
About 98 per cent of germinated conidia established their invasion through motor cells and the rest through stomatal pore, and no instances invading through other area were recongnized. After the invasion of infection hyphae into motor cells, abundant granular substances were deposited in the cells.
These granular substances were abundant in the cells of plants raised with excess potassium (8K and 3K) or excess nitrogen (6N) and a few in the cells of plant grown in nitrogen or potassium deficiency (1/4N or 1/4K). This granular degeneration of the cells seemed to be an indicative of plant resistant to the fungus, the deficient plant being susceptible to the fungal infection. Although no morphological difference was observed among the fungal hyphae on the tested plants, the infection hyphae seemed to be little narrower in the motor cells showed high glanular degeneration.
