在夏季高温条件下 ,杂交稻汕优 63、籼稻南京 14、粳稻武育粳的光合速率日变化曲线均为双峰型 ,上午和下午各有一高峰 ,中午有一低谷 ,即所谓“午睡”现象 ,但高峰和低谷出现的时刻不同 ,“午睡”出现的时刻也不同。这 3个水稻品种 (组合 )的光合速率与生态、生理因子存在一定的相关性 ,其中南京 14与光照强度的相关系数最大 The diurnal variation curves of photosynthetic rate of hybrid rice Shanyou 63, indica rice Nanjing 14 and japonica rice Wuyujing were both bimodal at summer high temperature, with a peak in morning and afternoon, a low valley at noon, the so-called “nap” phenomenon, But the peak and trough appear at different moments, “nap” appeared at different times. There was a certain correlation between photosynthetic rate and ecological and physiological factors of these three rice varieties (combinations), and the correlation coefficient between Nanjing 14 and light intensity was the highest