The xylem of anisohydric Quercus alba L. is more vulnerable to embolism than isohydric codominants
The xylem of anisohydric Quercus alba L. is more vulnerable to embolism than isohydric codominants
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DOI：
10.1111/pce.14244
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发表时间：
2021-12-29
影响因子：
7.3
通讯作者：
Novick, Kimberly A.
中科院分区：
文献类型：
--
作者：
Benson, Michael C.;Miniat, Chelcy F.;Novick, Kimberly A.
植物叶水势（psi（L））调节和木质部栓塞脆弱性的协调是理解碳吸收和水力损害风险之间的权衡的基础。有一个普遍的共识，即树木脆弱的木质部更保守地调节psi（L）比植物抗性木质部。我们评估了这种模式是否适用于美国东部三种重要的温带树种，糖槭和鹅掌楸，通过综合1600 psi（L）的观察，122木质部栓塞曲线和木质部解剖测量跨越10个森林明显的水文气候梯度和年龄。我们发现，出乎意料的是，最脆弱的木质部（Q。alba）对psi（L）的调节比其它物种的调节更不严格。这种关系被发现在所有的网站，这样的性状之间的协调在很大程度上不受气候和林分年龄。栎属物种被认为是最耐旱的温带美国森林物种之一，然而，我们的研究结果表明，他们相对宽松的psi（L）的调节，以应对水文压力发生大量的水力成本，可能会使他们面临新的风险，在一个更干旱的未来。
The coordination of plant leaf water potential (psi(L)) regulation and xylem vulnerability to embolism is fundamental for understanding the tradeoffs between carbon uptake and risk of hydraulic damage. There is a general consensus that trees with vulnerable xylem more conservatively regulate psi(L) than plants with resistant xylem. We evaluated if this paradigm applied to three important eastern US temperate tree species, Quercus alba L., Acer saccharum Marsh. and Liriodendron tulipifera L., by synthesizing 1600 psi(L) observations, 122 xylem embolism curves and xylem anatomical measurements across 10 forests spanning pronounced hydroclimatological gradients and ages. We found that, unexpectedly, the species with the most vulnerable xylem (Q. alba) regulated psi(L) less strictly than the other species. This relationship was found across all sites, such that coordination among traits was largely unaffected by climate and stand age. Quercus species are perceived to be among the most drought tolerant temperate US forest species; however, our results suggest their relatively loose psi(L) regulation in response to hydrologic stress occurs with a substantial hydraulic cost that may expose them to novel risks in a more drought-prone future.