Positive root pressure is critical for whole-plant desiccation recovery in two species of terrestrial resurrection ferns
Positive root pressure is critical for whole-plant desiccation recovery in two species of terrestrial resurrection ferns
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DOI：
10.1093/jxb/erz472
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发表时间：
2020-01-23
影响因子：
6.9
通讯作者：
Pittermann, Jarmila
中科院分区：
文献类型：
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作者：
Holmlund, Helen, I;Davis, Stephen D.;Pittermann, Jarmila
耐干燥（DT）生物可以失去几乎所有的水分而不会死亡。脱水耐受性允许生物体在几乎完全脱水的休眠状态下生存。在细胞水平上，糖和蛋白质稳定细胞成分并保护它们免受氧化损伤。然而，很少有研究的动力学和驱动程序的维管DT植物全株恢复。在维管DT植物中，整株植物的脱水恢复（复活）不仅取决于细胞的复水，而且还取决于获得水分不平等的器官的恢复。在这项研究中，在原位自然和人工灌溉实验揭示了两个DT蕨类植物的脱水恢复的动态。器官特定的灌溉实验表明，整个植物复活时，水供应到根，但叶水合（叶面吸水）是不够的中柱和根再水化。在这两个物种中，施加压力切除脱水复叶的叶柄复活远端叶组织，而单独毛细作用是不够的复活远端小羽片。复水后，根茎和中柱中的蔗糖水平急剧下降，淀粉水平上升，与积累的蔗糖作为脱水保护剂的作用一致。这些研究结果提供了深入了解的特点，促进干旱蕨类植物与查帕拉尔植被南部加州的脱水恢复。
Desiccation-tolerant (DT) organisms can lose nearly all their water without dying. Desiccation tolerance allows organisms to survive in a nearly completely dehydrated, dormant state. At the cellular level, sugars and proteins stabilize cellular components and protect them from oxidative damage. However, there are few studies of the dynamics and drivers of whole-plant recovery in vascular DT plants. In vascular DT plants, whole-plant desiccation recovery (resurrection) depends not only on cellular rehydration, but also on the recovery of organs with unequal access to water. In this study, in situ natural and artificial irrigation experiments revealed the dynamics of desiccation recovery in two DT fern species. Organ-specific irrigation experiments revealed that the entire plant resurrected when water was supplied to roots, but leaf hydration alone (foliar water uptake) was insufficient to rehydrate the stele and roots. In both species, pressure applied to petioles of excised desiccated fronds resurrected distal leaf tissue, while capillarity alone was insufficient to resurrect distal pinnules. Upon rehydration, sucrose levels in the rhizome and stele dropped dramatically as starch levels rose, consistent with the role of accumulated sucrose as a desiccation protectant. These findings provide insight into traits that facilitate desiccation recovery in dryland ferns associated with chaparral vegetation of southern California.