Xylem hydraulic safety and construction costs determine tropical tree growth
Xylem hydraulic safety and construction costs determine tropical tree growth
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DOI：
10.1111/pce.13106
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发表时间：
2018-03-01
影响因子：
7.3
通讯作者：
Oliveira, Rafael S.
中科院分区：
文献类型：
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作者：
Eller, Cleiton B.;Barros, Fernanda de V.;Oliveira, Rafael S.
热带树木的快速生长通常与较高的死亡率有关，但这种关系的机制却知之甚少。在这项研究中，我们调查树木的生长模式与环境条件和水力性状，通过监测形成层的生长9热带云雾林树种再加上数值模拟，使用优化模型。我们发现，快速生长的树木有较低的木质部安全边际比生长缓慢的树木，这种模式是不一定联系在一起的气孔行为或环境条件的差异时，发生增长。相反，快速生长的树木的木质部导管更容易受到空穴和低密度木材的影响。我们提出了生长-木质部脆弱性权衡代表了木材水力经济谱类似于经典的叶经济谱，并通过数值模拟表明，这种权衡可以出现从生长速率，木材密度和木质部之间的协调空化脆弱性。我们的研究结果表明，液压故障的脆弱性可能与热带树木的生长-死亡权衡，决定重要的生活史差异。这些发现对于进一步理解木质部的水力功能及其对植物碳经济的影响具有重要意义。
Faster growth in tropical trees is usually associated with higher mortality rates, but the mechanisms underlying this relationship are poorly understood. In this study, we investigate how tree growth patterns are linked with environmental conditions and hydraulic traits, by monitoring the cambial growth of 9 tropical cloud forest tree species coupled with numerical simulations using an optimization model. We find that fast-growing trees have lower xylem safety margins than slow-growing trees and this pattern is not necessarily linked to differences in stomatal behaviour or environmental conditions when growth occurs. Instead, fast-growing trees have xylem vessels that are more vulnerable to cavitation and lower density wood. We proposethe growth - xylem vulnerability trade-off represents a wood hydraulic economics spectrum similar to the classic leaf economic spectrum, and show through numerical simulations that this trade-off can emerge from the coordination between growth rates, wood density, and xylem vulnerability to cavitation. Our results suggest that vulnerability to hydraulic failure might be related with the growth-mortality trade-off in tropical trees, determining important life history differences. These findings are important in furthering our understanding of xylem hydraulic functioning and its implications on plant carbon economy.