ISHS Acta Horticulturae 171: I International Symposium on Water Relations in Fruit Crops
WATER TRANSPORT THROUGH THE ROOT |
| Author: | J. Dainty |
| Abstract:
Models for quantitatively describing the movement of water across the root, and indeed up the root xylem, of increasing complexity and reality are described and discussed. It is concluded that for most purposes the simplest, equivalent single membrane, model, with water and solute fluxes given by the equations of irreversible thermodynamics, is adequate even though interpreting parameters such as the reflection coefficient is not always easy. The latest ideas about the actual pathway(s) of water movement across the root are considered. It seems that there is a trend away from the general idea of movement in the cortical apoplast up to and through the endodermal cells and then in the stelar apoplast up to the xylem vessels. Recent experiments suggest that a cell-to-cell movement is more likely. But more experimental information is needed on the conductance of the apoplast, on swelling and shrinking of roots, etc. before we can be certain of the pathway. | |
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