Comparative hydraulic architecture of tropical tree species representing a range of successional stages and wood density
Comparative hydraulic architecture of tropical tree species representing a range of successional stages and wood density
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DOI：
10.1007/s00442-011-1973-5
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发表时间：
2011-09-01
期刊：
影响因子：
2.7
通讯作者：
Domec, Jean-Christophe
中科院分区：
文献类型：
--
作者：
McCulloh, Katherine A.;Meinzer, Frederick C.;Domec, Jean-Christophe
植物水力结构（PHA）与水分运输充分性、光合速率、生长形式和伴随的碳分配有关。尽管它的影响特征中央赋予整体竞争优势，在给定的环境中，很少有研究探讨PHA的关键方面是否指示演替阶段，特别是在成熟的个人。虽然它是公认的木材密度（WD）往往是较低的早期与晚期演替树种，WD可以影响PHA的其他方面，WD的相互作用，演替阶段和由此产生的影响PHA还没有得到充分的探讨。在这里，我们研究了PHA在木材解剖的尺度上的差异，以全树水力传导的物种在早期与晚期演替巴拿马热带森林。虽然干WD是没有区别的演替组之间，分支WD是较低的演替早期物种。在所有物种中，WD与血管直径呈负相关，与血管填充密度呈正相关。分支与主干导管直径之比、分支液流和全树叶片比导与分支WD呈负相关。先锋物种表现出更大的树液流量在分支比在树干和更大的叶比水力传导，这表明先锋物种可以移动更大量的水在一个给定的张力梯度。结合与较低WD相关的较大水储存容量，这些结果表明这些先锋物种可以节省构建更安全木质部所需的碳支出，而是允许更多的碳分配给快速生长。
Plant hydraulic architecture (PHA) has been linked to water transport sufficiency, photosynthetic rates, growth form and attendant carbon allocation. Despite its influence on traits central to conferring an overall competitive advantage in a given environment, few studies have examined whether key aspects of PHA are indicative of successional stage, especially within mature individuals. While it is well established that wood density (WD) tends to be lower in early versus late successional tree species, and that WD can influence other aspects of PHA, the interaction of WD, successional stage and the consequent implications for PHA have not been sufficiently explored. Here, we studied differences in PHA at the scales of wood anatomy to whole-tree hydraulic conductance in species in early versus late successional Panamanian tropical forests. Although the trunk WD was indistinguishable between the successional groups, the branch WD was lower in the early successional species. Across all species, WD correlated negatively with vessel diameter and positively with vessel packing density. The ratio of branch:trunk vessel diameter, branch sap flux and whole-tree leaf-specific conductance scaled negatively with branch WD across species. Pioneer species showed greater sap flux in branches than in trunks and a greater leaf-specific hydraulic conductance, suggesting that pioneer species can move greater quantities of water at a given tension gradient. In combination with the greater water storage capacitance associated with lower WD, these results suggest these pioneer species can save on the carbon expenditure needed to build safer xylem and instead allow more carbon to be allocated to rapid growth.