School of the Environment, Yale University, New Haven, Connecticut, USA.
Plant Physiol. 2021 Nov 3;187(3):1501-1518. doi: 10.1093/plphys/kiab361.
The epiphytic resurrection-or desiccation-tolerant (DT)-fern Pleopeltis polypodioides can survive extreme desiccation and recover physiological activity within hours of rehydration. Yet, how epiphytic DT ferns coordinate between deterioration and recovery of their hydraulic and photosynthetic systems remains poorly understood. We examined the functional status of the leaf vascular system, chlorophyll fluorescence, and photosynthetic rate during desiccation and rehydration of P. polypodioides. Xylem tracheids in the stipe embolized within 3-4 h during dehydration. When the leaf and rhizome received water, tracheids refilled after ∼24 h, which occurred along with dramatic structural changes in the stele. Photosynthetic rate and chlorophyll fluorescence recovered to predesiccation values within 12 h of rehydration, regardless of whether fronds were connected to their rhizome. Our data show that the epiphytic DT fern P. polypodioides can utilize foliar water uptake to rehydrate the leaf mesophyll and recover photosynthesis despite a broken hydraulic connection to the rhizome.
附生耐旱（DT）蕨类植物 Pleopeltis polypodioides 在极度干旱条件下可以存活，并在重新水合后的数小时内恢复生理活性。然而，附生耐旱蕨类植物如何协调其水力和光合作用系统的恶化和恢复仍然知之甚少。我们在 Pleopeltis polypodioides 的脱水和复水过程中检查了叶片维管束系统、叶绿素荧光和光合速率的功能状态。在脱水过程中，茎中的木质部管胞在 3-4 小时内栓塞。当叶片和根茎接收水分时，管胞在大约 24 小时后重新填充，这伴随着茎中的剧烈结构变化。无论叶片是否与根茎相连，复水 12 小时内，光合速率和叶绿素荧光都能恢复到脱水前的值。我们的数据表明，附生耐旱蕨类植物 Pleopeltis polypodioides 可以利用叶片水分吸收来重新水化叶片叶肉并恢复光合作用，尽管与根茎的水力连接已经中断。
