Abstract: Photoinhibition properties of super high yielding hybrid rice Ⅱyou 129 and its adaptation mechanism to strong light were investigated by measuring its light response curve, diurnal variation of net photosynthetic rate and chlorophyll fluorescence parameters of leaves, with hybrid rice Shanyou 63 as a control. Results indicated that photoinhibition of rice flag leaves under field conditions mainly resulted from increasing in thermal dissipation, especially for the thermal dissipation depended on xanthophyll cycle, but no destruction of photosynthetic apparatus. Super high yielding rice Ⅱyou 129 was more tolerant to photoinhibition than Shanyou 63. This is attributed to higher saturation light intensity and maximum net photosynthetic rate, more active xanthophyll cycle, and more rapid recovery after photoinhibition of Ⅱyou 129 compared to Shanyou 63.

Key words: rice, photoinhibition, chlorophyll fluorescence parameters, xanthophyll cycle

摘要： 通过测定田间高产杂交籼稻Ⅱ优129与对照汕优63的光响应曲线、光合速率和叶绿素荧光参数日变化，探讨了Ⅱ优129剑叶光合作用的光抑制特性及其对强光的适应机制。结果表明, 田间自然条件下杂交水稻叶片发生光抑制现象的主要原因是热耗散的增加，尤其是依赖叶黄素循环的热耗散的增加，而不涉及光合机构的破坏。具有超高产潜力的水稻品种Ⅱ优129比对照汕优63耐光抑制，其原因主要是Ⅱ优129具有较高的饱和光强、最大光合速率和叶黄素循环活力，遭受光抑制伤害后的恢复能力较强。

关键词: 水稻, 光抑制, 叶绿素荧光参数, 叶黄素循环