Abstract: The photosynthetic characteristics of indica-japonica cross combination and indica cross combination were identified under photooxidation and shading Conditions. Results showed that japonica rice 02428 and indica-japonica hybrid rice Yayou 2 were with photosynthetic characteristics adapted to wide range of light intensity; indica hybrid rice Shanyou 63 was tolerant to shading and sensitive to photooxidation; indica rice 3037, Minghui 63, Zhenshan 97A were sensitive to photooxidation and shading. The varieties with adaptation to wide rang of light intensity were characterized by less accumulation of toxic superoxide anion radical (O^-) higher induced activity of superoxide dismutase (SOD), an endogenous O^- scavenger and relative stability in photosynthetic key enzyme RUBPcase activity. Simultaneously, these varieties also possess relative stability in specific leaf weight and photosynthetic productivity under shading condition (1/5 nature light). At present, it would be necessary to be combined photosynthetic characteristics adapted to wide range of light intensity with improved plant-type for high-yield breeding.

Key words: Hybrid rice, Light adaptation, Photosynthetic characteristic, Photooxidation, Shading

关键词: 杂交稻, 光合作用, 品种, 适应性, 光氧化