【摘要】 植物光合作用对环境变化具有很强的自我调节和适应能力,温度不仅影响着植物生长发育及其地理分布,还影响了对光、水分、土壤等资源的利用效率。利用Li-6400气体交换测量系统测定灰胡杨叶片在不同温度下的光响应曲线,选取4种光响应模型对灰胡杨的光响应过程进行拟合比较和精度评定,筛选出5个温度下灰胡杨的最优模型。结果表明:灰胡杨是耐干旱却不耐高温的高光效植物,最适生长温度为25℃。通过模型拟合优度分析,4种光响应模型拟合精度存在差异,直角双曲线模型和非直角双曲线模型无法直接估算P_nmax和LSP,二次项回归拟合模型拟合值与实测值偏差较大,且有违背常识错误,直角双曲线修正模型能很好体现灰胡杨在不同光强下的光响应过程,且拟合得到的各项光合参数均接近实测,为最优模型,可作为荒漠地区灰胡杨的最优光响应曲线模型。更多还原

【Abstract】 Plant photosynthesis exhibits strong self-regulation and adaptability to environmental changes.Temperature significantly influences plant growth,development,geographical distribution,and the utilization efficiency of light,water,soil,and other resources.Using the Li-6400 gas exchange measurement system,the light response curves of Populus pruinosa leaves were measured at different temperatures.Four light response models were selected to fit and compare the photosynthetic response process of P.pruinosa.Model accuracy was evaluated to identify the optimal model across five temperature regimes.Results indicate that P.pruinosa is a drought-tolerant plant with high light-use efficiency but limited heat tolerance,exhibiting optimal growth at 25℃.Goodness-of-fit analysis revealed differences in the precision of the four models.The rectangular hyperbola and non-rectangular hyperbola models failed to directly estimate maximum net photosynthetic rate (P_nmax) and light saturation point（LSP）.The quadratic regression model produced values that substantially deviates from measured data and yielded biologically unrealistic results.In contrast,the modified rectangular hyperbola model accurately characterized the light response process of P.pruinosa across light intensities,with fitted photosynthetic parameters closely matching empirical measurements.Thus,we recommend this model as the optimal light response curve for P.pruinosa in desert ecosystems.更多还原