Although water is essential for photosynthetic activation in lichens, rates of vapor uptake and activation in humid air, which likely influence their niche preferences and distribution ranges, are insufficiently known. This study simultaneously quantifies rehydration kinetics and PSII reactivation in sympatric, yet morphologically and functionally distinct cephalolichens (Lobaria amplissima, Lobaria pulmonaria, Lobaria virens). High-temporal resolution monitoring of rehydrating thalli by automatic weighing combined with chlorophyll fluorescence imaging of maximal PSII efficiency (FV/FM) was applied to determine species-specific rates of vapor uptake and photosynthetic activation. The thin and loosely attached growth form of L. pulmonaria rehydrates and reactivates faster in humid air than the thick L. amplissima, with L. virens in between. This flexible hydration strategy is consistent with L. pulmonaria's wide geographical distribution stretching from rainforests to continental forests. By contrast, the thick and resupinate L. amplissima reactivates slowly in humid air but stores much water when provided in abundance. This prolongs active periods after rain, which could represent an advantage where abundant rain and stem flow alternates with long-lasting drying. Understanding links between morphological traits and functional responses, and their ecological implications for species at risk, is crucial to conservation planning and for modelling populations under various climate scenarios.

中文翻译：

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老林附生头孢菌中水化策略的功能权衡

尽管水对于地衣的光合作用激活至关重要，但对可能影响它们的生态位偏好和分布范围的潮湿空气中的蒸汽吸收和激活率尚不清楚。这项研究同时量化了同域但形态和功能不同的头孢菌（Lobaria amplissima、Lobaria pulmonaria、Lobaria virens）的补液动力学和 PSII 再激活。通过自动称重结合最大 PSII 效率 (FV/FM) 的叶绿素荧光成像对再水化菌体进行高时间分辨率监测，以确定物种特异性的蒸汽吸收率和光合活化率。L. pulmonaria 薄而松散附着的生长形式在潮湿空气中比厚 L. amplissima 再水化和重新激活更快，L. virens 介于两者之间。这种灵活的水化策略与 L. pulmonaria 从热带雨林到大陆森林的广泛地理分布是一致的。相比之下，厚重的回旋型 L. amplissima 在潮湿空气中缓慢重新激活，但在充足的情况下会储存大量水分。这延长了雨后的活跃期，这可能代表了一个优势，即丰富的雨水和茎流与长期干燥交替。了解形态特征和功能反应之间的联系，以及它们对濒危物种的生态影响，对于保护规划和各种气候情景下的种群建模至关重要。amplissima 在潮湿的空气中缓慢地重新激活，但在充足的情况下会储存大量的水分。这延长了雨后的活跃期，这可能代表了一个优势，即丰富的雨水和茎流与长期干燥交替。了解形态特征和功能反应之间的联系，以及它们对濒危物种的生态影响，对于保护规划和各种气候情景下的种群建模至关重要。amplissima 在潮湿的空气中缓慢地重新激活，但在充足的情况下会储存大量的水分。这延长了雨后的活跃期，这可能代表了一个优势，即丰富的雨水和茎流与长期干燥交替。了解形态特征和功能反应之间的联系，以及它们对濒危物种的生态影响，对于保护规划和各种气候情景下的种群建模至关重要。