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Drought stress recovery of hydraulic and photochemical processes in Neotropical tree saplings
Tree Physiology ( IF 4 ) Pub Date : 2021-07-23 , DOI: 10.1093/treephys/tpab092
Olivier Jean Leonce Manzi 1, 2, 3 , Maxime Bellifa 1 , Camille Ziegler 1, 4 , Louis Mihle 1 , Sébastien Levionnois 1, 5 , Benoit Burban 1 , Céline Leroy 1, 5 , Sabrina Coste 1 , Clément Stahl 1
Affiliation  

Abstract
Climate models predict an increase in the severity and the frequency of droughts. Tropical forests are among the ecosystems that could be highly impacted by these droughts. Here, we explore how hydraulic and photochemical processes respond to drought stress and re-watering. We conducted a pot experiment on saplings of five tree species. Before the onset of drought, we measured a set of hydraulic traits, including minimum leaf conductance, leaf embolism resistance and turgor loss point. During drought stress, we monitored traits linked to leaf hydraulic functioning (leaf water potential (ψmd) and stomatal conductance (gs)) and traits linked to leaf photochemical functioning (maximum quantum yield of photosystem II (Fv/Fm) and maximum electron transport rate (ETRmax)) at different wilting stages. After re-watering, the same traits were measured after 3, 7 and 14 days. Hydraulic trait values decreased faster than photochemical trait values. After re-watering, the values of the four traits recovered at different rates. Fv/Fm recovered very fast close to their initial values only 3 days after re-watering. This was followed by ETRmax, Ψmd and gs. Finally, we show that species with large stomatal and leaf safety margin and low πtlp are not strongly impacted by drought, whereas they have a low recovery on photochemical efficiency. These results demonstrate that πtlp, stomatal and leaf safety margin are a good indicators of plant responses to drought stress and also to recovery for photochemical efficiency.


中文翻译:

新热带树苗水力和光化学过程的干旱应力恢复

摘要
气候模型预测干旱的严重程度和频率会增加。热带森林是可能受到这些干旱严重影响的生态系统之一。在这里,我们探讨了水力和光化学过程如何应对干旱胁迫和重新浇水。我们对五种树种的树苗进行了盆栽试验。在干旱开始之前,我们测量了一组水力性状,包括最小叶导、叶栓塞阻力和膨压损失点。在干旱胁迫期间,我们监测了与叶片水力功能相关的性状(叶片水势 (ψ md ) 和气孔导度 ( g s ))和与叶片光化学功能相关的性状(光系统 II 的最大量子产量 ( F v / Fm ) 和最大电子传输速率 (ETR max )) 在不同萎蔫阶段。重新浇水后,在 3、7 和 14 天后测量相同的性状。水力特性值比光化学特性值下降得更快。重新浇水后,四个性状的值以不同的速度恢复。F v / F m在重新浇水后仅 3 天就恢复得非常快,接近其初始值。紧随其后的是 ETR max、 Ψ mdg s。最后,我们展示了气孔和叶片安全裕度大且 π tlp低的物种受干旱影响不大,但光化学效率的恢复率较低。这些结果表明 π tlp、气孔和叶片安全裕度是植物对干旱胁迫响应以及光化学效率恢复的良好指标。
更新日期:2021-07-23
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