Analysis of Developmental Factors Determining Yield and Its Application to Yield Prediction and Culture Improvement of Lowland Rice

[摘要] Treating the rice. plants to vary the amount of carbohydrates per grain supplied from leaves and culms, and subjecting the plants to the controlled temperatures (17, 21, 25 and 29°C), the authors tried to elucidate the mechanism of ripening. The following conclusion was drawn out, from the present experiment. The translocation rate of carbohydrates from leaves and culms to grains increases with temperatures up to 29°C which is the highest temperature used in the experiment, as far as the carbohydrates to be translocated exist enough in quantity. It has clearly been recognized, on the contrary, that the activity of grains in receiving the carbohydrates from leaves and culms decreases earlier as the temperature becomes hither. And, moreover, the respiratory loss of carbohydrates in the plant increases with temperatures. Consequently, the following facts obtained in the experiment can be well understood that the optimum temperature for ripening varies with the amount of carbohydrates per grain to be supplied from leaves and culms, that is the more the carbohydrates are supplied, the higher the optimum temperature is, and in fact the optimum temperatures are found in general from 21°C to 25°C in the average temperature of day and night.

[学科分类] 农业科学（综合）