On the context of future climate change, new habitats will be threatened and unique species will be forced to develop different strategies to survive. Saxifraga longifolia Lapeyr. is an endemic species from the Pyrenees with a very particular habitat. We explored the capacity and strategies of S. longifolia plants to face different severities of drought stress under both natural conditions and controlled water stress followed by a re-watering period of 20 days. Our results showed a role for abscisic acid (ABA), salicylic acid (SA) and cytokinins (CKs) in plant survival from drought stress, and as the stress increased, ABA lost significance and SA appeared to be more implicated into the response mechanisms. Moreover, photo-oxidative stress markers revealed that both xanthophyll cycles played a photoprotection role with a stronger participation of the lutein epoxide cycle as the stress was more intense. Severe drought decreased the maximum efficiency of photosystem II (Fv /Fm ) below 0.45, being this the limit to survive upon rewatering. Overall, our results proved different strategies of S. longifolia plants to cope with drought stress and suggested a Fv /Fm threshold to predict plant survival in high-mountain environments. This article is protected by copyright. All rights reserved.

中文翻译：

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比利牛斯山脉遗存物种严重干旱生存和恢复的策略

在未来气候变化的背景下，新的栖息地将受到威胁，独特的物种将被迫制定不同的生存策略。Saxifraga longifolia Lapeyr。是比利牛斯山脉的特有物种，栖息地非常特殊。我们探索了 S. longifolia 植物在自然条件下和受控水分胁迫下面对不同严重程度的干旱胁迫的能力和策略，然后再浇水 20 天。我们的结果表明脱落酸 (ABA)、水杨酸 (SA) 和细胞分裂素 (CKs) 在干旱胁迫下植物存活中的作用，并且随着胁迫增加，ABA 失去意义，SA 似乎更多地涉及响应机制。而且，光氧化应激标志物表明，随着压力的增加，叶黄素环氧化物循环的参与程度也更高，这两种叶黄素循环都发挥了光保护作用。严重干旱将光系统 II 的最大效率 (Fv /Fm ) 降低到 0.45 以下，这是重新浇水后生存的极限。总体而言，我们的结果证明了长叶 S. longifolia 植物应对干旱胁迫的不同策略，并提出了 Fv / Fm 阈值来预测高山环境中的植物存活率。本文受版权保护。版权所有。长叶植物应对干旱胁迫，并提出了 Fv / Fm 阈值来预测高山环境中的植物存活。本文受版权保护。版权所有。长叶植物应对干旱胁迫，并提出了 Fv / Fm 阈值来预测高山环境中的植物存活。本文受版权保护。版权所有。