The Role of Adenosine Tri-Phosphate in the Ripening of Rice Plant : II. Effect of temperature on adenosine tyi-phosohate content in rice kernel and hull during ripening period

摘要

Rice plants, cv. Leng Kwang, Nihonbare and Milyang 23, were placed after heading outdoors and at a low temperature (day: 20°C, night: 13°C). The relationship between the changes of ATP content in the kernel and the increase of kernel weight was investigated. The results are as follows. 1. When the plants were placed outdoors, ATP content of the rice kernel increased and the peak was observed l4 days after heading. Thereafter it decreased. On the other hand, at a low temperature the increase in ATP content of the rice kernel was much slower and its peak was observed 21 days after heading. 2. When the plants were placed outdoors, there was a rapid increase in the weight of the kernel 14 days after heading. On the other hand, at a low temperature the increase in the weight of the rice kernel was much slower than that of outdoors and it increased rapidly 21 days after heading. The pattern of increase in kernel weigllt was very similar to that of the changes in ATP content. 3. ATP content in hull was the highest at heading and then decreased. 4. ATP content in the hull of sterile grain was always much lower than that of fertile grains and there was hardly any increase in hull weight during the ripening period.