Abstract:Two hybrid rice Qingyou 159, Guangyou No.4 and their parents were used to study on the activities of Hill reaction and photophosphorylation, ATPase activity and ATP content. It was found that the activities of Hill reaction and photophosphorylation in leaves of both hybrids were much higher than those of their respective parents with marked heterobeltiosis and mid-parent heterosis, and showed significant positive correlation with photosynthetic rates. The activities of ATPase (Ca+ +-ATPase and Mg+ +-ATPase) and ATP content of leaves in both rice hybrids were much higher than those of their respective parents. Statistical analysis also showed that ATP content and activity of ATPase possessed marked heterobeltiosis and drid-parent heterosis, and were positive correlation with photosynthetic rates. These photosynthetic properties may be used as the indices of heterosis for rice hybrids of high photosynthetic rate.