抄録
With the aim of studying the growth and the susceptibility of rice to Helminthosporium disease as influenced by aeration and the kinds of mineral elements supplied, some solution culture experiments were carried out during 1948 and 1949 at Konosu farm of National Agricultural Experiment Station. Results of experiments are summarized as follows:- (1) Regardless of the kinds of mineral elements supplied, the plants growing in unaerated solution, to which saturated solution of hydrogen sulphide was added, showed the poor growth and the high susceptibility to Helminthosporium disease as compaired with the plants under aeration. (2) The deficiency of potassium, silica, manganese or magnesium decreased the plant growth and increased the susceptibility to the disease, regardless whether culture solution was aerated or not aerated. Addition of copper and iron bad also the same influence as above induced by the deficiency of potassium or such elements. While the deficiency of nitrogen decreased slightly the susceptibility. (3) The addition of sodium sulphate to the culture solution had no effect on the susceptibility under aeration, whereas it increased the susceptibility when the solution was not aerated. Such an unfavorable effect of sodium sulphate in the unaerated solution might be attributed to the injurious effect of hydrogen sulphide produced by the reduction of sulphate ion on root growth. (4) The plant growing in unaerated solution with H2S showed lower percentage content of potassium, manganese or silica in stem and leaves than that of the plant growing in the aerated solution. Such a low percentage content of nutrient elements in the former plant seems to be related to the retardation of absorptive function due to the root injury. (5) Supply of larger amount of H2S resulted in the poorer growth and higher susceptibility to the disease. However such an injurious effect of H2S was diminished by the addition of manganese.
