中国常见落叶阔叶树种低温损害模拟与预估

Low temperature damage could affect the growth and development of plants, and further alter the community structure and ecosystem productivity. Therefore, low temperature damage on plants in the context of climate change has been a hotspot of global change research. Low temperature damage on plants not only depends on the relative order of low temperature events and phenophases, but also is related to the resistance of plants to low temperature in different phenophases. To date, it is difficult to accurately simulate the changes of resistance to low temperature of plants due to the lack of specific measurement of the key parameters affecting plant growth. This project takes typical deciduous broadleaf plants in temperate regions of China as the research object. First, in the laboratory, the electrical conductivity of various organs of each species in different phenophases is measured to calculate its resistance to low temperature. The annual variation, inter-species difference and spatial difference of resistance to low temperature are analyzed. Subsequently, by combining historical phenological observation data, meteorological data and the key parameters of frost resistance obtained in the experiment, a frost-damage model coupled with phenological models is established to simulate the changes in resistance to low temperature and damage of plants. Finally, using the climate data projected from future climate scenarios, we predict the future low temperature damage risk of species in different regions of China. The aim of this project is to provide a scientific basis for understanding the effects of climate change on plant growth.

低温损伤能够影响植物的生长发育过程，并进一步改变群落结构和生态系统生产力。因此气候变化背景下的植物低温损伤是全球变化研究的热点。植物的低温损伤不仅取决于低温事件和物候期在时间上的先后，还与植物在不同物候期对低温的抗性相关。目前，植物的低温抗性变化模型准确性不高，低温影响植物生长的关键参数缺乏测算，这导致对植物低温损伤的预测存在较大不确定性。本项目以中国温带典型落叶阔叶植物为研究对象，首先通过室内实验测定各物种在不同物候期各器官的电导率，计算其抗冻性，分析抗冻性的年内变化规律、种间差异和空间差异；其次，结合历史物候观测资料、气象数据以及实验获取的抗冻性变化关键参数，构建耦合物候模型的低温损伤过程模型，在模型精确性验证的基础上，模拟植物在过去的抗冻性及低温损伤率变化；最后，利用气候情景数据，预估未来各物种在不同地区的低温损伤风险。通过上述研究，为深入理解气候变化对植物生长的影响提供科学基础。

气候变化背景下的植物低温损伤是全球变化研究的热点。本项目以10种中国温带典型落叶阔叶植物为研究对象，通过电导率实验测定了各物种在不同物候期各器官的抗冻性，分析了抗冻性的年内变化规律和种间差异；在此基础上，构建了耦合物候模型的低温损伤过程模型，并利用气候情景数据，预估了未来各物种在不同地区的低温损伤风险。研究结果表明：植物抗冻性以年为周期的变化与植物物候密切相关。其中，春季解除锻炼的起止时间分别对应芽开始膨大期和展叶盛期，秋季抗冻锻炼的起止时间对应植物叶开始变色期和休眠期；就种间差异而言，展叶越早的植物，叶片抗冻性越强；构建的植物低温损伤模型较好地模拟了各物种在不同温度条件下的损伤率，模型R2为0.73~0.94，RMSE为5.5~9.82%；在RCP4.5和RCP8.5情景下，大部分植物平均低温损伤均呈降低趋势，且在RCP8.5情景下降低幅度更大。就不同物种而言，白蜡、刺槐和榆树平均低温损伤降低幅度相对较小。本项目的研究成果可为深入理解气候变化对植物生长的影响提供科学基础。