标810S是温敏核不育系810S中的淡黄绿叶自然突变株,具有较高的光合速率.本文对突变体的光合色素、光合速率、荧光参数和光合关键酶活性等研究发现,标810S光合色素约为810S的一半,强光条件下标810S光合速率(Pn)比对照高,且没有明显的“午休”现象.标810S气孔导度(Gs)显著增加,叶绿素荧光动力学参数显示,标810S光量子转化效率高；光合酶1,5一二磷酸核酮糖羧化酶(RuBPCase)活性是对照的69.80％,磷酸烯醇式丙酮酸羧化酶(PEPCase)和NADP-苹果酸酶(NADH-ME)却比810S分别上升79.50％和69.06％.研究结果认为,光合色素含量下降是标810S叶片呈淡黄绿叶色的根本原因.突变体通过减少热耗散和提高光合电子传递速率来提高光能利用效率,为暗反应提供足够的同化力,而较高的PEPC活性和较大的气孔导度使其能更有效地固定C02,光反应和暗反应的协同使突变体具有较高的光合速率.%Biao 810S is a yellow-green leaf mutant of the thermosensitive genie male sterile (TGMS) rice which has higher photosynthetic rate. The photosynthetic characteristics of Biao 810S were studied with the wild type TGMS line 810S as a control to clarify the physiological basis of high photosynthetic efficiency and provide a theoretical basis for further utilization. The photosynthetic pigment, photosynthetic rate, fluorescence parameters and activity of photosynthetic key enzyme were measured. The content of photosynthetic pigment in Biao 810S was approximately half of that in 810S. However, the net photosynthetic rate of Biao 810S was higher than that of 810S under high intensity light and Biao 810S had no obvious "Midday depression" phenomenon. The stomatal conductance of Biao 810S was highly increased and the light quantum transformation efficiency was higher than that of 810S. The activity of ribulose-l,5-bisphosphate carboxylase (RuBPCase) in Biao 810S was 69.80% of that in 810S, but the activities of phosphoenolpyruvate carboxylase (PEPCase) and NADP-malic enzyme (NADP-ME) were 79.50% and 69.06% higher than those of 810S. The efficiency of light utilization in Biao 810S was enhanced by reduction of thermal dissipation and increase of electron transfer rate was generate sufficient assimilation power for the dark reactions. Consequently, the increased activities of PEPCase and stomatal conductance led to more effective fixation of CO2, and the synergistic effect of light reactions and dark reactions contributed to the higher photosynthetic rate of Biao 810S.
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