Key message

A high-risk hydraulic strategy might be linked to embolism recovery in Eucalyptus hybrids, allowing plants to have high hydraulic conductivity regardless of safety.

Abstract

Plants use a variety of strategies to mitigate or reduce drought-induced hydraulic failure. Recovery of hydraulic conductivity after drought stress can be an important mechanism used to avoid drought-induced mortality; however, the underlying mechanism of hydraulic recovery is still poorly understood. We examined the hydraulic recovery response between E. grandis × camaldulensis (GC) and E. urophylla × grandis (GU) after drought. We aimed to determine if there is a trade-off between xylem safety and hydraulic recovery and what the underlying mechanism might be. Destructive measurements together with X-ray microtomography measurements were used to determine the extent of hydraulic recovery at various time intervals. We found two distinct hydraulic strategies used by plants. GC was more resistant to embolism formation as compared to UG; however, GC showed lower levels of hydraulic recovery after rewatering. Larger vessel sizes were related to increases in drought vulnerability. Hydraulic recovery was also related to functional traits of cells surrounding vessels, highlighting the possible role that these cells play to increase hydraulic conductance in the xylem and increasing connectivity between vessels. Our study suggest that hydraulic recovery can be an important hydraulic strategy used by Eucalyptus hybrids in response to drought. A high-risk hydraulic strategy might be linked to embolism recovery, allowing plants to have high hydraulic resistance regardless of safety.

中文翻译：

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对切​​除的茎进行的测量表明，水力恢复可以成为桉树杂交种应对干旱的重要策略

关键信息

高风险的水力策略可能与桉树杂种的栓塞恢复有关，使植物无论安全性如何都具有高导水率。

抽象的

植物使用各种策略来减轻或减少干旱引起的水力故障。干旱胁迫后水力传导率的恢复可以成为避免干旱引起的死亡的重要机制；然而，水力回收的潜在机制仍然知之甚少。我们研究了E. grandis × camaldulensis ( GC ) 和E. urophylla × grandis ( GU )之间的水力恢复响应) 干旱后。我们旨在确定木质部安全性和液压恢复之间是否存在权衡以及潜在机制可能是什么。破坏性测量与 X 射线显微断层扫描测量一起用于确定不同时间间隔的水力恢复程度。我们发现了植物使用的两种不同的水力策略。与UG相比，GC对栓塞形成的抵抗力更强；然而，GC重新浇水后水力恢复水平较低。更大的船只尺寸与干旱脆弱性的增加有关。水力恢复还与血管周围细胞的功能特征有关，突出了这些细胞在增加木质部水力传导和增加血管之间的连通性方面可能发挥的作用。我们的研究表明，水力恢复可以成为桉树杂交种应对干旱的重要水力策略。高风险的水力策略可能与栓塞恢复有关，使植物无论安全性如何都具有高水力阻力。