Hydraulic architecture of some diffuse-porous trees
Hydraulic architecture of some diffuse-porous trees
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DOI：
10.1139/b78-274
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发表时间：
1978-09
期刊：
影响因子：
1.1
通讯作者：
M. Zimmermann
中科院分区：
文献类型：
--
作者：
M. Zimmermann
在重力流动条件下，通过茎、枝和枝条的每克叶片鲜重的木质部，测量并以每小时微升为单位测量了稀钾溶液通过茎、枝和树枝的部分的流动速度。这被称为叶特定电导率(LSC)。树干LSC不均匀，树干LSC高于枝条。此外，血管连接，如从茎到枝的路径，代表水力收缩。LSC在树中的分布主要基于不同的导管直径。在树干中，导管直径自上而下逐渐增大。它们在分枝中比在主茎中小，并且在每个分枝的根部有明显的直径收缩。从功能上讲，这意味着当蒸腾作用开始时，下侧叶木质部的压力必须比树顶部的木质部下降得更快。这也意味着，在水分胁迫条件下，树木的外围部分更具活力。
The rate of flow of a dilute KCl solution through sections of stem, branches, and twigs was measured and expressed in microlitres per hour, under conditions of gravity flow, per gram fresh weight of leaves supplied by that section of xylem. This is called leaf-specific conductivity (LSC). It is not uniform throughout the tree, LSC of the stem being higher than that of branches. Furthermore, vascular junctions, such as the path from stem to branch, represent hydraulic constrictions. Distribution of LSC in the tree is primarily based on varying vessel diameters. Vessel diameters increase from top to bottom in the tree stem. They are smaller in branches than in the main stem, and there is a distinct constriction of diameters at the base of each branch. Functionally this means that when transpiration begins the pressure has to drop more rapidly in the xylem of lower lateral leaves than in those at the top of the tree. It also means that under conditions of water stress peripheral parts of the tree are more vu...