Abstract: Using three hybrid rice combinations Shanyou 63, Qingyouzao and Xiuyou 57 grown in field (natural condition) as material, effect of chilling (5℃) and light (210 μmol m^-2s^-1 PFD) on chlorophyll fluorescence at 77K of flag leaves in hybrid rice F₁ and its parents were investigated. Results showed that the parameters of fluorescence, Fo, Fm and Fv were decreased by chilling treatment. The cold tolerance among three hybrid rice combinations could be reflected from variable fluorescence. The cold tolerance of F₁ hybrid rice was between that of male sterile line and restorer line. During chilling under low light Fo, Fm and Fv increased but Fv/Fm and Fv/Fo did not change. It was demonstrated that the chilling treatment with the lower light intensity had no significant effects on the efficiency of the primary conversion of the light energy of PSⅡ and the transport rate of the light energy of PSⅡ as compared with that of under growing condition. So, the photoinhibition was not occurred in the photochemical reaction of photosynthesis. Based on this result, the flag leaves taken from the field under strong light intensity, under 5℃ and 210μmol m^-2s^-1PFD treatment, light 210 μmol m^-2s^-1PFD might facilitate the adaptation of rice to chilling so that the degree of injury of photochemical process in leaves was reduced.

Key words: Chilling, Flag leaf, Hybrid rice, Light, Fluorescence

摘要： 以大田栽培的三套杂交水稻组合汕优63、青优早和秀优57为材料， 研究了低温(5℃)与光照(210 μmol m^-2 s^-1 PFD)对杂交水稻F₁及其亲本剑叶77K荧光的影响。结果表明：低温引起77K荧光参数F0、Fm、Fv下降，可变荧光Fv的变化能反映三套杂交水稻组合间的抗冷性的差异。F₁的抗冷性居父母本之间。同时发现，在低光照下低温处理引起Fo，Fm，Fv上升，但未改变Fv／Fm，Fv／Fo的比值。证明在低温下，低于水稻生长光强210μmol m^-2 s^-1 PFD的光照对PSⅡ的最初光能转化效率和光能传递速率影响不大， 即对光合作用的光化学过程未产生光抑制现象。由此可见，取样于田间强光照下的水稻剑叶，在5℃和210μmol m^-2 s^-1 PFD 处理下，210μmol m^-2 s^-1 PFD可能有利于水稻对低温的适应， 从而减轻叶片的光化学过程的伤害程度。

关键词: 杂交稻, 剑叶, 低温, 光照, 77K荧光