石漠化区银合欢林光响应曲线模型比较

以桂西南石漠化山地8年生银合欢退耕林为研究对象，采用直角双曲线模型、非直角双曲线模型、指数模型、修正直角双曲线模型，拟合银合欢的光饱和型、光抑制型、未饱和型和弱光型4种光响应曲线，同时比较不同模型计算所得光饱和时的最大净光合速率(P_max)、暗呼吸速率(R_d)、光补偿点(LCP)、光饱和点(LSP)等光合生理指标的估计精度。结果表明：修正直角双曲线模型对各类光响应曲线类型的拟合效果最好，判定系数为0.991 8~0.999 8，且仅其可以描述光抑制现象。修正直角双曲线模型和指数模型对P_max估计精度较高，修正直角双曲线模型对R_d和LCP预测效果最佳。综合光响应曲线拟合和光合生理参数预测效果来看，修正直角双曲线模型可作为石漠化区银合欢退耕林的最优光响应曲线模型。

Comparison of Photosynthesis-light Response Curve Models for Leucaena glauca Plantation in Karst Area

In this study, rectangle hyperbola model, nonrectangle hyperbola model, exponential model and modified rectangle hyperbola model were conducted to fit photosynthesis-light response curves the in the 8 years old Leucaena glauca plantation in karst area. The photosynthesis-light response curves were divided into 4 types of saturation curve, inhibition curve, unsaturation curve and weak light curve. Maximum net photosynthetic rate(Pmax), dark respiration rate(Rd), light compensation point(LCP), light saturation point(LSP)were also calculated and compared. The results showed that modified rectangle hyperbola model has the best goodness of fit of all types of photosynthesis-light response curves(R2 were between 0.991 8 and 0.999 8), and was only suitable for fitting inhibition curve. Modified rectangle hyperbola model and exponential model could predict Pmax better than the others. Modified rectangle hyperbola model also had best estimation accuracy for Rd and LCP. In summary, modified rectangle hyperbola model was the optimal model for photosynthesis-light response curves fitting of L.glauca plantation in karst area.