在武汉地区七、八月的气候条件下,水稻剑叶的a/b呈现出7:00-9:30的高比值,午后15-17点比值降到最低,傍晚又略有回升。叶绿素a/b比值的日变化与叶绿素b呈显著或极显著的负相关,而与叶绿素a则看不出相关性。短时间的恒温(30℃)与恒温加全光照或全黑暗,能改变这种变化的幅度和出现高低比值的时间,但仍表现出相似于自然光温条件下的变化节奏,说这明叶绿素a/b比值的日变化可能是植物长期适应外界环境条件所形成的一种内部节律,不易为短时间的温光等条件的改变而消失。 In July and August in Wuhan, the a / b of rice flag leaves showed a high ratio of 7: 00-9: 30, with the ratio of 15-17 in the afternoon dropping to its lowest level and a slight rebound in the evening. The diurnal variation of chlorophyll a / b ratio had a significant or extremely significant negative correlation with chlorophyll b, but no correlation with chlorophyll a. Short time constant temperature (30 ℃) with constant temperature plus full light or dark, can change the magnitude of this change and the ratio of high and low time, but still showed similar to the natural light and temperature changes in the rhythm, saying that the chlorophyll a The daily variation of the ratio of / b may be an internal rhythm formed by long-term adaptation of the plant to external environmental conditions, and it is not easy to disappear for a short time under the conditions of temperature and light.