Under 35-30°C, the ripening at early stages was promoted and more carbohydrate and nitrogen in the straw were transported into panicles, but at later stages they were retained in the straw as a result of early ceases of the panicles to receive them. The respiration of both grains and leaves at 35-30°C was higher at an early ripening period, but was lower at the later period than that at 25-20°C (Fig. 4 left). However, the respiration rate estimated at 30°C of grains being ripened under 35-30°C was always lower than that of grains under 25-20°C (Fig. 4 right). The respiration rate similarly measured of the boot leaf grown at high temperature was higher at early stages, but a little lower at later stages than that of the leaf grown at lower temperature (Fig. 5). It was considered that the earlier drop of physiological activity in the plant treated under high temperature had a keen relation with the earlier stop of ripening.