WATER-UPTAKE BY PLANTS .2. ROOT CONTACT MODEL
WATER-UPTAKE BY PLANTS .2. ROOT CONTACT MODEL
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DOI：
10.2136/sssaj1977.03615995004100060004x
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发表时间：
1977-01-01
影响因子：
2.9
通讯作者：
GARDNER, WR
中科院分区：
文献类型：
--
作者：
HERKELRATH, WN;MILLER, EE;GARDNER, WR
在根系吸水的标准分析中，假设根膜阻力与土壤阻力串联，而土壤阻力取决于土壤水分扩散率。用此标准模型预测的根系拔出率与土壤含水量和土壤水势的关系与分根试验的结果进行了比较。理论预测的萃取率是实测值的8倍。理论和实验之间的合理拟合只能通过在理论计算中假设生根密度比实验中测量的小100倍来获得。开发了一种替代模型，强调根-土接触效应的可能性。据推测，随着土壤干燥，与土壤接触的根的表面积减少，这导致了根膜阻力的增加。通过假设有效根膜透性与土壤相对饱和度成正比，得到了比传统理论更好的拟合结果。
In the standard analysis of root water uptake, it is assumed there is a constant root membrane resistance in series with a soil resistance which is dependent upon the soil moisture diffusivity. The relation of root extraction rate to soil water content and to soil water potential predicted by this standard model was compared to the results of divided root experiments. The extraction rates predicted by the theory were as much as 8 times larger than the measured values. A reasonable fit between theory and experiment could only be obtained by assuming in the theoretical calculations that the rooting density was 100 times smaller than that measured in the experiments. An alternative model emphasizing the possibility of a root-soil contact effect was developed. It was assumed that as the soil dried, the surface area of the roots in contact with the soil decreased, which caused an increase in the root membrane resistance. By assuming that the effective root membrane permeability was simply proportional to the relative saturation of the soil, a much better fit to the data was obtained than by using the conventional theory.