中文摘要：

光合作用是作物产量和品质形成的基础,直接受到叶片含氮量的影响。该文通过不同定植期不同氮素处理试验,建立了不同光温条件下温室黄瓜叶片适宜氮浓度的求算方程,并定量分析了不同光温条件下黄瓜叶片最大总光合速率与叶片氮浓度的关系。在此基础上,进一步建立了适合不同光温条件的温室黄瓜花后叶片最大总光合速率与叶片氮浓度关系的通用模型,并用与建模相独立的试验数据对模型进行了检验。结果表明,建立的模型能较好地预测不同定植期黄瓜叶片氮浓度对叶片最大总光合速率的影响。模型对温室黄瓜叶片最大总光合速率的预测结果与实测结果之间基于1：1直线的决定系数和均方根差分别为0.83和1.56μmol·m-2·s-1。建立的模型可以为温室黄瓜周年生产的氮素精确管理提供理论依据与决策支持。

英文摘要：

Leaf photosynthesis rate, as one of the most important physiological processes affecting crop yield and product quality, is strongly affected by leaf nitrogen concentration. Experiments with four nitrogen treatments and sowing dates were conducted in greenhouses in Shanghai during 2003 to 2005. The seasonal time course of the optimal leaf nitrogen concentration（N%opt） for photosynthesis was found to be an exponential function of the physiological development time after transplanting（PDT）. The relationship between the ratio of the maximum leaf gross photosynthesis rate with nitrogen deficiency （Pgmaxi） to that without nitrogen deficiency（Pgmax0） （PR=Pgmaxi/ Pgmax0） and the ratio of the actual leaf nitrogen concentration（N%） to the optimal leaf nitrogen concentration（N%opt） （NR=N%/N%opt） was also found to be an exponential function. Based on these quantitative relationships, a general model was developed to estimate the effects of leaf nitrogen concentration on the maximum leaf gross photosynthesis rate of greenhouse cucumber under different radiation and temperature conditions. Independent experimental data were used to validate the model. The coefficient of determination（R2） and the root mean squared error（RMSE） between the estimated and the measured maximum leaf gross photosynthesis rate based on the 1 ： 1 line were 0.83 and 1.56 pmol CO2·m^-2·s^-1, respectively. The model developed in this study gives satisfactory estimation of the maximum leaf gross photosynthesis rate of greenhouse cucumber growing during different seasons, hence it can be used to optimize nitrogen management for greenhouse cucumber production under different PAR and temperature conditions.