从油松苗木的水力结构探讨管道模型

Discussing the pipe model through hydraulic architecture of Pinus tabulaeformis seedlings.

为探讨管道模型的合理性 ,该文应用水力结构的基本理论 ,在温室条件下 ,用改良的冲洗法测定 4年生油松苗木各部位的水力结构参数 .实验和模拟的结果表明 ,苗木各部分木质部的导水率、比导率和叶比导率差异很大 ,限速区的导水率明显低于非限速区 ,供给单位叶量生长的功能木质部组织投入量也不是定值 ,即胡伯尔值是变化的 .因此 ,尽管管道模型已在一些领域被认可 ,但从苗木水分生理的角度 ,管道模型的前提假设是有局限的 。

In the paper, the basic theory of hydraulic architecture is used. The hydraulic architecture parameters of Pinus tabulaeformis seedlings(4 years old) are measured by improved flushing method under the condition of controlling drought gradient in the green house, in order to discuss the rationality of the pipe model. The results of experiment and simulation show that the differences of hydraulic conductivity, specific conductivity and leaf specific conductivity are great in different parts of seedlings. The hydraulic conductivity of non constriction area is higher than that of constriction area. The functional xylem devotion for unit leaf growth is not a constant, namely, the Huber value is diverse. Even though the pipe model has been accepted in some areas, its precondition is not perfect, and it is helpless in correctly understanding the essence of the seedling water physiology from the prospective of physiology.