Stem water transport of Lithocarpus edulis, an evergreen oak with radial-porous wood.
Stem water transport of Lithocarpus edulis, an evergreen oak with radial-porous wood.
复制标题
DOI：
10.1093/treephys/25.2.221
复制
发表时间：
2005-02
期刊：
影响因子：
4
通讯作者：
S. Hirose;A. Kume;S. Takeuchi;Yasuhiro Utsumi;K. Otsuki;S. Ogawa
中科院分区：
文献类型：
--
作者：
S. Hirose;A. Kume;S. Takeuchi;Yasuhiro Utsumi;K. Otsuki;S. Ogawa
对常绿阔叶橡树 Lithocarpus edulis (Mak.) Nakai 的茎导水系统进行了研究。属于栎科的常绿阔叶橡树（石果树、栲树、青冈树、栎树）是亚洲季风林的主要组成部分，其特点是拥有放射状多孔木材。径向多孔木材的一个特征是在径向定向的容器之间形成聚合射线。我们测量了茎横截面中血管内腔直径的分布，并计算了木材的理论水导率。在现场条件下测量了完整整棵树的热脉冲速度（HPV）的径向分布，并与水电导率的理论分布进行了比较。冷冻茎切片的软 X 射线照片表明，大部分血管内腔充满了水，包括 20 多年的血管。即使血管相对较宽（管腔直径 > 100 微米），空化现象也可以忽略不计。切下的茎基部的吸水率与 HPV 密切相关（r = 0.96），并且 HPV 密切反映了传感器探头周围每茎截面积的平均体积流量（SFVS）。然而，射线组织强烈抑制热传递，并且探针的定位强烈影响HPV的绝对值。研究还发现，HPV 比 SFVS 更能反映血管中的平均液流速度。
The stem water conducting system of an evergreen broad-leaved oak, Lithocarpus edulis (Mak.) Nakai, was investigated. Evergreen broad-leaved oaks (Lithocarpus, Castanopsis, Cyclobalanopsis, Quercus) belonging to the Quercoideae are a major component of Asian monsoon forests, and are characterized by the possession of radial-porous wood. A characteristic of radial-porous wood is the development of aggregate rays between radially oriented files of vessels. We measured the distribution of vessel lumen diameters in a stem cross section and calculated the theoretical water conductivity of the wood. The radial profile of the heat pulse velocity (HPV) was measured for an intact whole tree under field conditions and compared with the theoretical distribution of water conductivity. Soft X-ray photographs of frozen stem sections indicated that most of the vessel lumina were filled with water, including those of vessels more than 20 years old. Even when vessels were relatively wide (lumen diameters > 100 microm), cavitation was negligible. The rate of water uptake from the cut stem base correlated closely with HPV (r = 0.96), and HPV closely reflected the mean volume flow per stem sectional area (SFVS) around the sensor probes. However, the ray tissue sharply inhibited heat transfer, and the positioning of the probes strongly affected the absolute value of HPV. It was also found that HPV more closely reflected the mean sap flow velocity in the vessels than did SFVS.