Studies on the Nutrition of the Rice Plant with Reference to the Occurrence of the So-Called "Akagare" Disease. : IV. Occurrence of the disease as influenced by the conditions of cultivation and its relationship with the metabolism of the plant.

[摘要] The occurrence of "Akagare" disease of rice plant was tested by pot experiments using paddy soil on which the disease habitually occurs. Use of densely sown seedlings, heavy application of nitrogen and deep submergence of irrigation water promoted the occurrence of the disease, while use of sparsely sown seedlings and upland seedlings, dense planting per hill and drainage in midsummer decreased its occurrence. The occurrence of the disease correlated highly with the increase in soluble-N content, soluble-N/protein-N ratio, ratio, the decrease in starch accumulation in leaf sheath and the enhancement of peroxidase activity in lower leaves. The respiratory rate also showed correlation, although not significant, with the occurrence of the disease. From these results the occurrence of the disease seems to be closely connected with the decrease in starch content and the increase in soluble-N content, both likely to be caused by increase of respiration, and with the increase in peroxidase activity.

[学科分类] 农业科学（综合）