Ecophysiological strategies and functional trait syndromes as predictors for plant performance under different resource limitation in grassland

欧洲草原暴露于干旱事件的强度和频率的变化和氮（N）的可用性以下的气候变化，氮沉降和土地利用。目前的研究表明，使植物在干旱和氮限制条件下保持高水平表现的性状部分相似，部分相反。例如，高的根冠比可以提高植物对干旱和氮限制的抗性;但光合水分利用效率（WUE）应尽可能高以提高抗旱性，而低WUE和高蒸腾速率可以促进氮限制条件下的氮吸收。此外，干旱和氮的有效性相互作用，通过耦合的水和氮的吸收对植物的性能的影响。在这种情况下，我们的理解最佳适应共同限制，特别是在植物种间竞争的条件下，是特别差。下一个前沿是i）确定性状综合征，使植物在干旱和N共同限制的条件下最大限度地利用其资源（获取和保护），ii）阐明其背后的生理机制，iii）估计植物竞争对手之间互补资源利用的潜力。这些知识对于预测欧洲草原生态系统的未来具有重要意义。为了实现这些目标，计划进行三项相关实验，其中两项将在法国Moulis的CNRS理论和实验生态站（塞特）进行，申请人将由Grégoire Freschet博士主持。这些实验将在温室中接近自然条件下进行，包括对水的可用性和氮添加量的全因子操纵。第三项实验将是在法国蒙彼利埃的Ecotron设施借调期间进行的卫星研究，将与Alexandru Milcu博士合作进行。它将研究在非常严格控制的环境条件下水的利用和氮的吸收的生理生态机制。

European grasslands are exposed to changes in the strength and frequency of drought events and the availability of nitrogen (N) following changes in climate, N deposition and land-use. Current research shows that traits that allow plants to maintain a high level of performance under drought versus N limitation conditions are partly similar, partly contrasting. As an example, a high root to shoot ratio increases plant resistance to both drought and N limitation; but photosynthetic water use efficiency (WUE) should be as high as possible to improve drought resistance, whereas low WUE and high transpiration rates can facilitate N uptake in conditions of N limitation. Additionally, drought and N availability interact in their influence on plant performance via the coupling of water and N uptake. In this context, our understanding of optimal adaptations to co-limitation, and especially so under conditions of plant interspecific competition, is particularly poor. The next frontier is to i) identify trait syndromes that allow plants to maximize their resource use (acquisition and conservation) under conditions of drought and N co-limitation, ii) shed light on the physiological mechanisms that underlie them, and iii) estimate the potential for complementary resource use among plant competitors. Such knowledge is of major importance to predict the future of European grassland ecosystems.To meet these aims, three connected experiments are planned, of which two will take place at the Theoretical and Experimental Ecology Station (SETE), CNRS, Moulis, France, where the applicant will be hosted by Dr. Grégoire Freschet. These experiments will be conducted under close to natural conditions in greenhouses and include a full-factorial manipulation of water availability and nitrogen addition. The third experiment will be a satellite study during a secondment at the Ecotron facilities, Montpellier, France, and will be conducted in collaboration with Dr. Alexandru Milcu. It will examine ecophysiological mechanisms of water use and N uptake in very closely controlled environmental conditions.