Estimation of conduit taper for the hydraulic resistance model of West et al.
Estimation of conduit taper for the hydraulic resistance model of West et al.
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DOI：
10.1093/treephys/21.10.697
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发表时间：
2001-07-01
期刊：
影响因子：
4
通讯作者：
Gribben, RJ
中科院分区：
文献类型：
--
作者：
Becker, P;Gribben, RJ
West，Brown和Enquist(1999)的模型表明，如果维管导管足够锥化，树木的总水力阻力可以与路径长度无关。原始模型根据导管半径和管段数量定义了锥度系数a，但在旧管柱中可能很难区分管段。严格遵循West等人的定义和假设，我们推导出了几个基于气管半径和流道长度测量的i的估计式。然而，除了West等人的体积填充模型之外，还引入了一个附加参数b，以允许沿流动路径的管段长度变化的不同模型，包括固定长度模型和中间版本。其中一个新方程被拟合到以前发表的两个树种的数据中，以说明根据路径-长度关系估计导管锥度的方法，这被证明对b的变化非常敏感。建议了改进这种分析的抽样方案。
The model of West, Brown and Enquist (1999) showed that total hydraulic resistance in trees can be independent of path length, provided that vascular conduits taper sufficiently. The original model defined the coefficient of taper, a, in terms of conduit radius and segment number, but segments can be difficult to distinguish in old stems. Adhering strictly to the definitions and assumptions of West et al., we derived several equations for the estimation of I based on measurements of tracheary radius and flow path length. However, an additional parameter, b, was introduced to permit different models of variation in the length of segments along the flow path besides the volume-filling model of West et al., including a fixed-length model and intermediate versions. One of the new equations was fitted to previously published data for two tree species to illustrate the estimation of conduit taper from path-length relations, which proved quite sensitive to variation in b. Sampling protocols for improving such analyses are suggested.