Ecological differentiation in xylem cavitation resistance is associated with stem and leaf structural traits
Ecological differentiation in xylem cavitation resistance is associated with stem and leaf structural traits
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DOI：
10.1111/j.1365-3040.2010.02231.x
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发表时间：
2011-01-01
影响因子：
7.3
通讯作者：
Bongers, Frans
中科院分区：
文献类型：
--
作者：
Markesteijn, Lars;Poorter, Lourens;Bongers, Frans
抗气穴性是热带树种耐旱性的一个关键决定因素，但人们对其与生活史策略的关系知之甚少，特别是对于季节性干旱森林，这是一个由水资源变化严重驱动的系统。我们分析了脆弱性曲线的13个不同的生活史和叶物候的热带干旱森林树种的幼树。我们研究了如何脆弱性空化（P-50）相关的旱季叶水势和茎和叶性状。P-50值范围为-0.8至-6.2 MPa，先驱者平均比耐荫者更容易受到空化作用的影响38%。空化的脆弱性与结构性状赋予组织应力脆弱性，与木材密度呈负相关，令人惊讶的是最大血管长度。空蚀易损性与Huber值和叶片干物质含量呈负相关，与叶片大小呈正相关。这与SLA无关。我们发现了一个很强的抗气蚀性和水力效率之间的权衡。大多数物种在该领域的叶水势远高于其P-50，但先锋和落叶物种有较小的水力安全裕度比耐荫和常绿。水力安全和效率之间的权衡是这些热带干旱森林树种生态分化的基础。
Cavitation resistance is a critical determinant of drought tolerance in tropical tree species, but little is known of its association with life history strategies, particularly for seasonal dry forests, a system critically driven by variation in water availability. We analysed vulnerability curves for saplings of 13 tropical dry forest tree species differing in life history and leaf phenology. We examined how vulnerability to cavitation (P-50) related to dry season leaf water potentials and stem and leaf traits. P-50-values ranged from -0.8 to -6.2 MPa, with pioneers on average 38% more vulnerable to cavitation than shade-tolerants. Vulnerability to cavitation was related to structural traits conferring tissue stress vulnerability, being negatively correlated with wood density, and surprisingly maximum vessel length. Vulnerability to cavitation was negatively related to the Huber-value and leaf dry matter content, and positively with leaf size. It was not related to SLA. We found a strong trade-off between cavitation resistance and hydraulic efficiency. Most species in the field were operating at leaf water potentials well above their P-50, but pioneers and deciduous species had smaller hydraulic safety margins than shade-tolerants and evergreens. A trade-off between hydraulic safety and efficiency underlies ecological differentiation across these tropical dry forest tree species.