Drought response strategies define the relative contributions of hydraulic dysfunction and carbohydrate depletion during tree mortality
Drought response strategies define the relative contributions of hydraulic dysfunction and carbohydrate depletion during tree mortality
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DOI：
10.1111/nph.12064
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发表时间：
2013-02-01
期刊：
影响因子：
9.4
通讯作者：
Pinkard, Elizabeth A.
中科院分区：
文献类型：
--
作者：
Mitchell, Patrick J.;O'Grady, Anthony P.;Pinkard, Elizabeth A.
植物在干旱期间的生存需要活组织中足够的水合作用和碳水化合物储备以维持和恢复。我们假设树木的生长和水力策略决定了生理干旱的强度和持续时间，从而影响在死亡过程中水力功能丧失和碳水化合物消耗的相对贡献。globulus、E. Smithii）表现出高生长率和水利用，导致水分状况和水力传导率的快速下降。相反，辐射松的保守生长和水分关系导致了较长时间的负碳平衡和所有器官中储存的碳水化合物的显着消耗。持续呼吸对碳水化合物的持续需求突出了干旱持续时间在促进碳水化合物消耗中的作用，揭示了两种干旱策略，植物调节水分状态的差异：植物最大化气体交换，但暴露于低水势和快速水力功能障碍;和严格的气体交换调节以碳水化合物耗尽为代价。这些研究结果提供了证据之间的关系水力调节水分状况和碳水化合物消耗在终端干旱。
Plant survival during drought requires adequate hydration in living tissues and carbohydrate reserves for maintenance and recovery. We hypothesized that tree growth and hydraulic strategy determines the intensity and duration of the physiological drought, thereby affecting the relative contributions of loss of hydraulic function and carbohydrate depletion during mortality.We compared patterns in growth rate, water relations, gas exchange and carbohydrate dynamics in three tree species subjected to prolonged drought.Two Eucalyptus species (E. globulus, E. smithii) exhibited high growth rates and water-use resulting in rapid declines in water status and hydraulic conductance. In contrast, conservative growth and water relations in Pinus radiata resulted in longer periods of negative carbon balance and significant depletion of stored carbohydrates in all organs. The ongoing demand for carbohydrates from sustained respiration highlighted the role that duration of drought plays in facilitating carbohydrate consumption.Two drought strategies were revealed, differentiated by plant regulation of water status: plants maximized gas exchange, but were exposed to low water potentials and rapid hydraulic dysfunction; and tight regulation of gas exchange at the cost of carbohydrate depletion. These findings provide evidence for a relationship between hydraulic regulation of water status and carbohydrate depletion during terminal drought.