Entry of Water Into the Plant
The movement of water around the hydrological cycle takes place in response to a series of merging potential gradients, the water moving because there is nothing to stop it; obviously at some point in the cycle a substantial quantity of energy must be injected and as we have seen this comes from the sun and is used almost entirely in the conversion of liquid water into vapour at the evaporating and transpiring surfaces of the soil and plant. All the rest of the movements including those now to be described take place because the potential at the lower end of each stage exceeds that at the other end, and so the water flows. Its movement up the plant depends on the water having sufficient cohesion to remain in intact columns in spite of the tension exerted by removal (evaporation) of water from their upper ends. This concept is therefore known as the cohesion-tension theory.
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- NEWMAN, E. I. (1969). Water movement to plant roots. In Techniques used in soil investigations Rept Welsh Soils Discussion Group, University College of Wales, Aberystwyth, No. 10, 1–12. Critical discussion, supported by mathematical argument, of the movement of water towards and into the root system.Google Scholar