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(P_max), dark respiration rate(R_d), 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 P_max better than the others. Modified rectangle hyperbola model also had best estimation accuracy for R_d 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.