AMAP (Botanique et Modélisation de l'Architecture des Plantes et des Végétations), Université de Montpellier, CIRAD, CNRS, INRAE, IRD, 34000, Montpellier, France.
INRAE, UMR EcoFoG, CNRS, CIRAD, AgroParisTech, Université des Antilles, Université de Guyane, 97310, Kourou, France.
New Phytol. 2023 Jul;239(2):576-591. doi: 10.1111/nph.18973. Epub 2023 May 24.
Water stress can cause declines in plant function that persist after rehydration. Recent work has defined 'resilience' traits characterizing leaf resistance to persistent damage from drought, but whether these traits predict resilience in whole-plant function is unknown. It is also unknown whether the coordination between resilience and 'resistance' - the ability to maintain function during drought - observed globally occurs within ecosystems. For eight rainforest species, we dehydrated and subsequently rehydrated leaves, and measured water stress thresholds for declines in rehydration capacity and maximum quantum yield of photosystem II (F /F ). We tested correlations with embolism resistance and dry season water potentials (Ψ ), and calculated safety margins for damage (Ψ - thresholds) and tested correlations with drought resilience in sap flow and growth. Ψ thresholds for persistent declines in F /F , indicating resilience, were positively correlated with Ψ and thresholds for leaf vein embolism. Safety margins for persistent declines in F /F , but not rehydration capacity, were positively correlated with drought resilience in sap flow. Correlations between resistance and resilience suggest that species' differences in performance during drought are perpetuated after drought, potentially accelerating shifts in forest composition. Resilience to photochemical damage emerged as a promising functional trait to characterize whole-plant drought resilience.
水分胁迫会导致植物功能下降，即使在重新水合后也会持续存在。最近的研究定义了“弹性”特征，这些特征描述了叶片对干旱持续损害的抗性，但这些特征是否能预测整个植物功能的弹性尚不清楚。也不知道在全球范围内观察到的弹性和“抗性”（在干旱期间维持功能的能力）之间的协调是否发生在生态系统内。对于八种热带雨林物种，我们对叶片进行了脱水和再水合处理，并测量了再水合能力和光合作用系统 II 最大量子产量（F/F）下降的水分胁迫阈值。我们测试了与栓塞抗性和旱季水势（Ψ）的相关性，并计算了损伤的安全裕度（Ψ-阈值），并测试了与蒸腾流和生长中干旱恢复力的相关性。F/F 持续下降的Ψ阈值（表明弹性）与 Ψ和叶片叶脉栓塞的阈值呈正相关。F/F 持续下降的安全裕度（但不是再水合能力）与蒸腾流中的干旱恢复力呈正相关。抗性和弹性之间的相关性表明，物种在干旱期间的表现差异在干旱后会持续存在，这可能会加速森林组成的变化。对光化学损伤的弹性作为一种有前途的功能特征，可用于描述整个植物的干旱恢复力。
