Low-temperature stress in late spring poses a serious threat to winter wheat production. In three-year environment-controlled phytotron experiments at both elongation and booting stages, we observed that short-term low-temperature stress decreased leaf area and stem, limited leaf photosynthetic system, and severely reduced grain yield, especially in the low-temperature sensitive cultivar. To better quantify the effects of low-temperature stress on leaf photosynthesis rate (Pn), leaf area index (LAI), biomass partitioning, and grain yield, the lethal temperature at 50% mortality (LT50), low-temperature damage index (LDI), and process-based algorithms were proposed and incorporated into the WheatGrow model. The algorithms take into account the effects of low-temperature with different durations and reflected a low-temperature sensitivity of cultivars at different growth periods by using LT50. The improved WheatGrow model could reproduce well the observed dynamics of the decrease of Pn during the treatment period, recovery of Pn after cold treatments, and the damage to LAI and biomass accumulation under the low-temperature stress treatments. Compared to the original model, RMSE of Pn, LAI, total aboveground biomass, and grain yield in the improved WheatGrow model were reduced by 63 to 77% under low-temperature stress. Although the newly developed algorithms expand crop modeling capacity into quantifying the impacts of low-temperature stress on wheat productivity, further assessments with observed data under field conditions are still required, especially for obtaining suitable parameters at the regional scale.

晚春低温胁迫对冬小麦生产构成严重威胁。在为期三年的伸长期和孕穗期环境控制植物生长试验中，我们观察到短期低温胁迫会减少叶面积和茎，限制叶片光合系统，严重降低粮食产量，特别是在低温敏感品种。为了更好地量化低温胁迫对叶片光合速率（Pn）、叶面积指数（LAI）、生物量分配和籽粒产量的影响，采用50%死亡率致死温度（LT50）、低温损伤指数（LDI ）)，并提出了基于过程的算法并将其纳入 WheatGrow 模型。该算法考虑了不同持续时间的低温影响，利用LT50反映了不同生育期品种对低温的敏感性。改进后的 WheatGrow 模型可以很好地再现观察到的处理期间Pn降低、冷处理后Pn恢复以及低温胁迫下对LAI和生物量积累的损害的动态。与原始模型相比，Pn 、LAI的RMSE，在低温胁迫下，改进的 WheatGrow 模型中的总地上生物量和粮食产量减少了 63% 至 77%。尽管新开发的算法扩展了作物建模能力，以量化低温胁迫对小麦生产力的影响，但仍需要在田间条件下使用观测数据进行进一步评估，尤其是在区域范围内获得合适的参数。