Modelling climate change impacts on yield and quality of crops based on leaf photosynthesis with acclimation to elevated CO2

气候因子平均值的预测变化（大气二氧化碳浓度增加、温度升高、降水模式改变）和气候变率的预测变化（极端事件的频率、持续时间和程度，如高温和霜冻期、干旱、洪水和风暴）将影响农作物的产量和质量。虽然已经研究了许多这些气候因子对农作物初级生产的影响，但对植物生物量化学成分的影响知之甚少。关于如何模拟和模拟气候对植物内部化学物质（即宏量和微量营养物质、糖、淀粉、酚类物质）的运输和转化过程的影响，人们所知的就更少了，这些化学物质决定了作物的质量参数（如谷物的碳氮比）。这种过程知识对于预测未来作物产量的质量是必要的。因此，P5项目将基于改进的叶片光合作用和资源配置动态子模型，开发并试验一种新的作物生长模型。该模型的重点将放在光合作用对二氧化碳浓度升高的适应上，二氧化碳浓度升高会导致叶片氮含量降低和籽粒碳氮比升高。新的子模型将扩展作为Expert-N农业生态系统模型一部分的作物模型CERES、SPASS、SUCROS和GECROS。

Predicted changes in average values of climate factors (increased atmospheric CO2 concentration, increased temperature, altered precipitation patterns) and predicted changes in climatic variability (frequencies, duration and degree of extremes such as heat and frost periods, droughts, floods and storms) will impact on the yield and quality of agricultural crops. Whereas effects of many of these climatic factors on primary production of agricultural crops have been investigated, little is known about the impact on the chemical composition of plant biomass. Even less is known about how to model and simulate climatic effects on the plant internal transport and transformation processes of chemicals (i.e. macro- and micro-nutrients, sugars, starch, phenolics) that determine crop quality parameters (e.g. carbon to nitrogen (C/N) ratio of grains). Such process knowledge is necessary to predict the quality of future crop yields. The project P5, therefore, will develop and test a new crop growth model based on improved sub-models of leaf photosynthesis and resource allocation dynamics. The model focus will be on the acclimation of photosynthesis to elevated CO2 concentrations which leads inter alia to lower leaf N contents and higher C/N ratios of grains. The new sub-models will extend the crop models CERES, SPASS, SUCROS and GECROS that are part of the agro-ecosystem model Expert-N.