Abstract: The chloroplast light reaction characteristics were compared between super-high-yield hybrid rice Liangyoupeijiu and traditional hybrid rice Shanyou 63 intending to provide theoretical insights into physiological basis for high yield. Using fluorescence dynamics analysis and physiological and biochemical research techniques, in the field we systematically studied the primary response, electron transport chain and photophosphorylation during the reproductive period. The results showed that: (1) as compared to Shanyou 63, chlorophyll content in functional leaves of Liangyoupeijiu was 22.90% higher, it had a relatively longer photosynthetic function duration and chla/chlb ratio was 36.78% higher; (2) there was no significant difference in light absorption per unit leaf area of functional leaves, but Liangyoupeijiu maintained a high light energy absorption capacity and long stability period , the number of active reaction centers was more, the energy of heat dissipation was relatively lower, the energy transferred into the electron transport chain was higher; (3) fluorescence analysis showed that structures and status of the body side, the receptor side and the reaction center in PSII performed better than those of Shanyou 63, indicating that Liangyoupeijiu had a higher efficiency in the transforming light energy into electric energy; (4) in addition, oxygen evolution of the chloroplast, activities of electron transport chain and photophosphorylation were significantly higher, indicating that Liangyoupeijiu possessed some advantages in the energy convertsion from electric energy to active chemical energy. With higher light energy absorption, transmission and conversion efficiency, Liangyoupeijiu established a physicological basis of super-high-yield.

Key words: Fluorescence dynamics, Functional leaves, Primary response, Electron transport chain and photophosphorylation, Photosynthetic function duration, the body side, the receptor side and the reaction center of PSII