Abstract Desiccation tolerance (DT) in vegetative tissues is not a common ability, especially in Angiosperms. Barbacenia genus is distributed in tropical seasonally dry environments, such as rock outcrops, in South America. Some of the Barbacenia species are described as DT and are able to tolerate drastic water loss of their tissues during the desiccation process and to reestablish their metabolism after rehydration. In order to better understand this ability, we evaluated aspects related to leaf water status, gas exchange, photosynthetic pigments content and chlorophyll a fluorescence of B. graminifolia, during 32 days of water deprivation followed by rehydration. Carbon assimilation (A) remained active until the 24th day, when volumetric soil moisture was below 10%. Leaf relative water content (RWC) remained constant during 28 days of water withholding, decreasing significantly after this period, followed by the lowest gas exchange parameters and maximum quantum efficiency of photosystem II (Fv/Fm), and the highest degradation rates of chlorophyll and carotenoids in the course of the desiccation period. After rehydration, RWC was rapidly recovered, as well as Fv/Fm and photosynthetic parameters. This time frame was not enough for total recovery of A rates due, probably, to the slow restoration of chlorophyll a content. We classify, therefore, the species as a resurrection plant. Despite the similar decrease of photosynthetic rates found in other DT species before reaching the desiccated state, B. graminifolia maintains CO2 assimilation even under low soil water availability (10%) as physiological strategy when submitted to severe water deficit.

中文翻译：

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Barbacenia graminifolia，一种具有高保水能力的复活植物

摘要 营养组织的干燥耐受性（DT）不是一种常见的能力，尤其是在被子植物中。Barbacenia 属分布在热带季节性干燥的环境中，例如南美洲的岩石露头。一些 Barbacenia 物种被描述为 DT，并且能够在干燥过程中耐受其组织的剧烈失水，并在再水化后重新建立新陈代谢。为了更好地了解这种能力，我们在 32 天的缺水和补水期间评估了与禾本科植物的叶片水分状态、气体交换、光合色素含量和叶绿素 a 荧光相关的方面。碳同化 (A) 一直活跃到第 24 天，此时土壤体积水分低于 10%。叶片相对含水量 (RWC) 在 28 天的停水期间保持不变，此后显着下降，其次是光系统 II (Fv/Fm) 的最低气体交换参数和最大量子效率，以及最高的叶绿素和在干燥期间的类胡萝卜素。复水后，RWC、Fv/Fm和光合参数迅速恢复。这个时间范围不足以完全恢复 A 率，可能是由于叶绿素 a 含量的缓慢恢复。因此，我们将该物种归类为复活植物。尽管在达到干燥状态之前在其他 DT 物种中发现光合速率类似降低，但 B.