不同水分条件下胡杨光响应曲线拟合模型比较

本研究通过测量不同水分条件下胡杨（Populus euphratica Oliv.）叶片的光响应曲线，并采用4种光响应模型对其光合特征参数拟合值与实测值进行比较，分析了不同水分条件下光响应曲线模型对胡杨适用性的影响机制。结果表明，当水分供应充足时，胡杨非直角双曲线模型对暗呼吸速率（R_d）的拟合效果最优，直角双曲线修正模型拟合光饱和点（LSP）、最大净光合速率（P_nmax）、光补偿点（LCP）的结果与实测值较接近；但当胡杨受到水分亏缺后，直角双曲线修正模型对P_nmax和光饱和点（LSP）的拟合效果最优，直角双曲线模型对R_d和LCP的拟合效果最佳。因此，水分条件有利时胡杨应用直角双曲线修正模型、非直角双曲线模型较好；水分亏缺条件下采用直角双曲线修正模型、直角双曲线模型更为适合。

Comparison of light response models of photosynthesis in Populus euphratica Oliv.grown under contrasting groundwater conditions

We measured the light response curves of Populus euphratica grown under contrasting experimental groundwater conditions.We assessed the applicability of the light response models for P.euphratica under different groundwater conditions by comparing fitted photosynthetic characteristic parameters with measured values using four classic models.Results showed that the LSP,P_nmax,and LCP parameters under well-watered conditions were best fit by the modified rectangular hyperbola model,whereas R_d was better estimated by the non-rectangular hyperbola model.For P.euphratica under water deficit conditions,the rectangular hyperbola model exhibited better estimation for R _d and LCP,whereas the modified rectangular hyperbola model was more suitable for estimating P_nmax and LSP.Overall,our results suggest that when considering model choice for estimating the light response parameters of P.euphratica,the modified rectangular hyperbola model and non-rectangular hyperbola model are applicable for plants grown under benign water environments,but the modified rectangular hyperbola model and rectangular hyperbola model are preferable for those under water deficit environments.This study helps clarifying the light response processes of P.euphratica under different moisture conditions and provides a theoretical basis for photosynthetic characteristics.