Vulnerability to cavitation in leaves is the result of highly adaptive anatomical and physiological traits that can be linked to water availability in a species’ climate of origin. Despite similar gross leaf morphology, eucalypt species are often confined to specific climate envelopes across the variable rainfall environments of Australia. In this study, we investigate how the progression of cavitation differs among eucalypts and whether this is related to other hydraulic and physical leaf traits. We used the Optical Visualisation technique to capture cavitation progression across the leaves of eight eucalypt species (Angophora crassifolia, Corymbia tessellaris, Eucalyptus atrata, Eucalyptus grandis, Eucalyptus laevopinea, Eucalyptus longifolia, Eucalyptus macrandra, Eucalyptus tereticornis) from a wide range of climates and grown in a common garden setting. Vulnerability to cavitation, represented by the leaf water potential required for 50% cavitation of leaf vessels, varied significantly among species (−3.48 MPa to −8.25 MPa) and correlated linearly with home climate precipitation and leaf SLA (R² of 0.64 and 0.75, respectively). P12-P88, the range of water potentials between which 12% to 88% of cavitation occurs, was decoupled from P50 but also correlated with leaf SLA (R² of 0.72). We suggest the magnitude of P12-P88 may be representative of a species’ drought strategy – a large P12-P88 signifying leaves that exhibit drought tolerance (retention of leaves under drought conditions) and a small P12-P88 signifying drought avoidance (leaf shedding after a threshold of drought is reached). Our results agree with other studies that highlight these cavitation metrics as genetically fixed traits. Turgor loss point, on the other hand, may be more plastic, as evidenced by the low variability of this trait across these eucalypt species grown in a common garden environment. Further study will help to establish the SLA-related anatomical traits that impart cavitation resistance and to extend these conclusions to a greater number of species and home climates.

中文翻译：

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空化的脆弱性与八个桉树物种的家庭气候降水有关

叶片中空化的脆弱性是高度适应性的解剖和生理特征的结果，这些特征可能与物种起源气候中的水可用性有关。尽管总体叶片形态相似，但桉树物种通常仅限于澳大利亚多变的降雨环境中的特定气候范围。在这项研究中，我们调查了桉树之间空化的进展如何不同，以及这是否与其他水力和物理叶片特性有关。我们使用光学可视化技术来捕捉八种桉树（Angophora crassifolia、Corymbia tessellaris、Eucalyptus atrata、Eucalyptus grandis、Eucalyptus laevopinea、Eucalyptus longifolia、Eucalyptus) 来自各种气候，并在常见的花园环境中生长。对空化的脆弱性，以叶血管 50% 空化所需的叶水势为代表，在物种之间存在显着差异（-3.48 MPa 至 -8.25 MPa），并且与家庭气候降水和叶片 SLA 呈线性相关（R ²为 0.64 和 0.75，分别）。P12-P88 是发生 12% 到 88% 空化的水势范围，它与 P50 脱钩，但也与叶片 SLA（R ²0.72）。我们认为 P12-P88 的大小可能代表了一个物种的干旱策略——一个大的 P12-P88 表示叶片表现出耐旱性（干旱条件下叶片保留）和一个小的 P12-P88 表示避免干旱（叶片脱落后达到干旱阈值）。我们的结果与其他研究一致，这些研究强调这些空化指标是基因固定的特征。另一方面，Turgor 损失点可能更具可塑性，正如在普通花园环境中生长的这些桉树物种的这一特性的低变异性所证明的那样。进一步的研究将有助于建立与 SLA 相关的解剖特征，这些特征赋予抗空化能力，并将这些结论扩展到更多的物种和家庭气候。