Studies on the Nutrition of Rice Plant with Reference to Hellminthosporiu Leaf Spot (Preliminary report). : VIII. Varietal Differences of the Rice Plant in the Growth Retardation and in the Increase of Disease Susceptibility Caused by Hydrogen Sulphide.

[摘要] To elucidate the relation between the resistance of the rice varieties to Hellminthosporium leaf spot and "Akiochi" and the resistance to the root-rot caused by hydrogen sulphide, the authors carried out a solution culture experiment in which five varieties, differing in the degree of resistance to the diseases and "Akiochi", were grown with and without hydrogen sulphide. The result of the expriment was as follows: (1) Irrespective of the varieties, the addition of hydrogen sulphide to nutrient solution caused the root-rot, and the top growth of the plant was retarded. Normal development of the flower and grain was, therefore, inhibited, resulting in the loss of yield. The susceptibility of the plant to the disease was also increased by hydrogen sulphide. (2) The degree of root-rot infestation, the retardation of top growth and the increase in the susceptibility to the disease by hydrogen sulphide were all lower in Norin-37, a variety which is highly resistant to the disease and "Akiochi", as compaired with the other varieties, less resistant or more susceptible to the disease. (3) Varietal differences in the susceptibility to the disease were observed more clearly in the plants grown with hydrogen sulphide than in those grown without it. (4) From the result of the chemical analysis of the plants of the two varieties (Norin-37 and Norin-8), differing from each other in the degree of resistance to the disease and root-rot, no clear difference was found between them either in the nutrient contents or in the susceptibility to the disease. (5) In rice varieties, the loss of yield caused by hydrogen sulphide appeared to have a more intimate relation to the root-rot rather than to the increase of the susceptibility due to hydrogen sulphide.

[学科分类] 农业科学（综合）