基于气候生态位预测的来自不同生物群系和生活史的山龙眼属（山龙眼科）物种木质部空穴化的脆弱性。

Vulnerability to xylem cavitation of Hakea species (Proteaceae) from a range of biomes and life histories predicted by climatic niche.

机构信息

Hawkesbury Institute for the Environment, Western Sydney University, Richmond, New South Wales 2751,Australia.

Department of Plant Biology and Biotechnology, Faculty of Life Sciences, University of Benin, Benin City, Nigeria.

出版信息

Ann Bot. 2021 Jun 24;127(7):909-918. doi: 10.1093/aob/mcab020.

DOI:10.1093/aob/mcab020

PMID:33606015

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC8225280/

Abstract

BACKGROUND AND AIMS

Extreme drought conditions across the globe are impacting biodiversity, with serious implications for the persistence of native species. However, quantitative data on physiological tolerance are not available for diverse flora to inform conservation management. We quantified physiological resistance to cavitation in the diverse Hakea genus (Proteaceae) to test predictions based on climatic origin, life history and functional traits.

METHODS

We sampled terminal branches of replicate plants of 16 species in a common garden. Xylem cavitation was induced in branches under varying water potentials (tension) in a centrifuge, and the tension generating 50 % loss of conductivity (stem P50) was characterized as a metric for cavitation resistance. The same branches were used to estimate plant functional traits, including wood density, specific leaf area and Huber value (sap flow area to leaf area ratio).

KEY RESULTS

There was significant variation in stem P50 among species, which was negatively associated with the species climate origin (rainfall and aridity). Cavitation resistance did not differ among life histories; however, a drought avoidance strategy with terete leaf form and greater Huber value may be important for species to colonize and persist in the arid biome.

CONCLUSIONS

This study highlights climate (rainfall and aridity), rather than life history and functional traits, as the key predictor of variation in cavitation resistance (stem P50). Rainfall for species origin was the best predictor of cavitation resistance, explaining variation in stem P50, which appears to be a major determinant of species distribution. This study also indicates that stem P50 is an adaptive trait, genetically determined, and hence reliable and robust for predicting species vulnerability to climate change. Our findings will contribute to future prediction of species vulnerability to drought and adaptive management under climate change.

摘要

背景与目的

全球范围内极端干旱条件正在影响生物多样性，对本地物种的生存构成严重威胁。然而，针对多样化植物群，我们尚未获得有关生理耐受能力的定量数据，无法为保护管理提供参考。本研究通过量化多样化的帚木属（山龙眼科）对空穴化的生理抗性，检验了基于气候起源、生活史和功能特征的预测。

方法

我们在一个人工气候室中对 16 个物种的复份植株的末端枝条进行采样。在离心力作用下，使枝条的木质部产生不同的水势（张力），并以特征张力生成 50%电导率丧失（茎 P50）作为衡量空穴化抗性的指标。同一枝条用于估计植物功能特征，包括木材密度、比叶面积和胡伯值（比叶面积与流面积的比值）。

主要结果

物种间的茎 P50 存在显著差异，与物种的气候起源（降雨量和干旱度）呈负相关。空穴化抗性在生活史之间没有差异；然而，具有圆柱状叶形态和较大胡伯值的干旱规避策略可能对物种在干旱生物群落中的定殖和生存至关重要。

结论

本研究强调了气候（降雨量和干旱度），而不是生活史和功能特征，是空穴化抗性（茎 P50）变化的关键预测因子。起源物种的降雨量是预测空穴化抗性的最佳指标，可解释茎 P50 的变化，这似乎是物种分布的主要决定因素。本研究还表明，茎 P50 是一种适应性特征，由遗传决定，因此可靠且稳健，可用于预测物种对气候变化的脆弱性。我们的研究结果将有助于未来预测物种对干旱的脆弱性和适应气候变化的管理。