土壤水分对冬小麦叶片光合速率影响模型构建

植物叶片光合速率是表征植物光合能力的重要参数，对土壤水分反应敏感，建立不同土壤水分对冬小麦叶片光合速率影响模型，有助于准确理解冬小麦的光合作用和产量形成。该文收集整理了1996—2017年我国冬小麦主产区11个试验地点、17个冬小麦品种的干旱和渍水试验数据共64组310个样本，分别构建干旱和渍水对冬小麦叶片光合速率影响的分段式和指数型模型，形成土壤水分对冬小麦叶片光合速率影响模型（the model for Soil Moisture Effects on leaf Photosynthesis rate of winter wheat，SMEP）。结果表明:随着土壤相对湿度增加，冬小麦叶片光合速率系数呈稳定低值-线性增加-稳定高值-缓慢下降的特点；随着渍水时间延长，冬小麦叶片光合速率系数呈缓慢下降-快速下降的特点。对SMEP模型进行回代检验、外推检验、单点验证、单发育期验证发现，模型模拟结果与文献数据有较好的一致性，回归系数在1.0附近，且均达到0.01显著性水平。SMEP模型将嵌入中国农业气象模式（CAMM1.0），为CAMM不断完善提供科技支撑。

Construction of the Model for Soil Moisture Effects on Leaf Photosynthesis Rate of Winter Wheat

The rate of leaf photosynthesis, which is sensitive to soil moisture, is one of the most important parameters to characterize the photosynthetic capacity of plants. Constructing a model which can reveal effects of soil moisture on leaf photosynthesis rate of winter wheat will be helpful to accurately understand the photosynthesis and yield formation. A total of 310 photosynthesis rate samples under different soil moistures, including 227 drought stress samples in 50 tests and 83 waterlogging stress samples in 14 tests, are jointly collected from 17 winter wheat cultivars at 11 experimental sites via the published references. However, photosynthesis rates of winter wheat are quite different between different cultivars, different developmental stages, and different experimental sites. Normalized photosynthesis rate coefficients for winter wheat are derived by calculating the ratio of leaf photosynthesis rate under different water stresses and CK. And then, segmental and exponential models are established for effects of drought and waterlogging stresses on leaf photosynthesis rate of winter wheat, respectively. The model for soil moisture effects on leaf photosynthesis rate of winter wheat (SMEP) is correspondingly constructed. Photosynthesis rate coefficients of winter wheat leaves show the trend of "stable low value-linear increase-stable high value-slow decrease" with the increase of soil relative moisture. Meanwhile, photosynthesis rate coefficients exhibit characteristics of "slow decline-rapid decline" with the prolongation of waterlogging stress. Four tests, including back-training test, extrapolation test, single-site test and certain developmental stage test, are also done to validate the SMEP model. Generally, the results simulated by the SMEP model are in good agreement with the records in the literatures. The linear regression coefficients are all around 1.0, and the regression equations all pass the significant test of 0.01. SMEP model will be coupled to Chinese Agro-Meteorological Model (CAMM1.0), providing scientific and technological supports for the continuous improvement of CAMM1.0.