CO2对植物在光补偿点附近量子效率的影响

应用植物光合作用对光响应修正模型研究了CO2浓度分别为380和600 mol·mol-1时,栾树和辣椒在光补偿点附近光合量子效率的改变及Kok效应。结果表明:光响应修正模型可很好地拟合栾树和辣椒2种CO2浓度下的光响应曲线,且获得的光合参数与实测值相符合;2种不同CO2浓度条件下,栾树和辣椒总是存在初始量子效率(φ0)大于光补偿点处的量子效率(φc),光合量子效率在光补偿点附近不是常数,且与暗呼吸速率无关;CO2浓度的大小影响着栾树的Kok效应,但对辣椒的Kok效应影响不明显,分析认为,这是由于栾树在光补偿点附近光合量子效率的改变来自其净光合速率对光强的非线性响应,而辣椒不存在Kok效应。

Effects of CO2 concentration on the quantum yield in the vicinity of plant light compensation point

By using a modified model of light-response curve of plant photosynthesis, this paper studied the effects of different concentration CO2 (380 and 600 μSymbolm·mol·mol-1) on the variations of quantum yield in the vicinity of light compensation point and the Kok effect of Koelreuteria paniculata and Capsicum annuum L. The modified model fitted well the light-response curves of the photosynthesis of K. paniculata and C. annuum at 380 and 600 μSymbolm·mol·mol-1 of CO2, and the photosynthetic parameters estimated by the modified model were in very close agreement with the measured data. The initial slope of the curve (φ0) was greater than the quantum yield in the light compensation point of K. paniculata and C. annuum, and the quantum yield in the vicinity of the light compensation point was not a constant, and did not relate with dark respiration rate. Moreover, C. annuum at 380 and 600 μSymbolm·mol·mol-1 of CO2 did not exist Kok effect. CO2 concentration affected the Kok effect of K. paniculata but less affected the Kok effect of C. annuum. It was considered that the variation of the quantum yield in the vicinity of light compensation point of K. paniculata was come from the nonlinear response of the net photosynthesis rate to irradiance, but the Kok effect was not existed for C. annuum.