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本文以植物根系吸水的人工模拟试验所测得的资料为依据,运用水流的电模拟原理,定量分析了土壤-植物-大气连统体(SPAC)中水流阻力各分量的大小、变化规律及其相对重要性。 SPAC中主要的水流阻力发生在水分进入植物根系和离开植物叶片这两个对称的连接“链条”上。根系吸收阻力和气孔扩散阻力是决定液态水流速度和水汽扩散速度的重要因素,二者的最大值由植物本身性质决定。土根接触阻力当土壤含水量较低时,与根系吸收阻力为同一数量级,最大值能达到土根总阻力的70％以上。土壤阻力和植物内部对液态水流的传导阻力相对较小。
Based on the data measured by artificial simulation of plant root water uptake, this paper uses the electric simulation principle of water flow to quantitatively analyze the size and variation of each component of water flow resistance in soil-plant-atmosphere combined body (SPAC) Relative importance. The main water flow resistance in SPACs occurs on two symmetric connection “chains” where moisture enters the plant’s roots and leaves the plants. Root absorption resistance and stomatal diffusion resistance are important factors that determine the rate of liquid water flow and the rate of water vapor diffusion. The maximum of the two is determined by the nature of the plant itself. Soil resistance to root contact When the soil moisture content is low, the resistance to root absorption is the same order of magnitude, and the maximum value can reach more than 70% of the total root resistance. Soil resistance and plant internal resistance to liquid water flow resistance is relatively small.