Difference Of Water Potential Moves The Water Transport On Plants Cells

The survival of plant cells depends on its ability to balance water uptake and expenditure. Intake or a net expenditure of water by a cell occurs through osmosis, passive transport of water through a membrane. How can we predict the direction of osmosis when a cell is surrounded by a certain solution? In the case of animal cells, is sufficient for us if we know whether it hypotonic extracellular solution (a concentration of dissolved substances is lower) or hypertonic (has a concentration of dissolved substances is higher) relative to the cell, water will move due to osmosis from the hypotonic to hypertonic. However, in the case of plants, the presence of cell wall into the second factor that affects osmosis: the existence of physical pressure. Effect of combination of these two factors–concentration of the solute and pressure–called water potential.
The important thing is that the water will move across the membrane from solution with high water potential to a solution with a lower water potential. For example, if a plant cell immersed in a solution that has a higher water potential than the cell itself, then the osmotic water uptake will cause the cells to swell. By moving water can do work (eg enlarge the cell). Potential component of water potential refers to potential energy, namely the capacity to carry out work when water moves from areas with higher water potential to regions with lower water potential. This situation is a special case about general trends in the system to change spontaneously to the lowest free energy state.
For example, a soft cell (water potential 0) soaked in a solution with solute concentration which is higher than the cell itself. Because the external solution has a smaller water potential, water will leave the cell by osmosis, so that cells would undergo plasmolysis or shrink and move away from the walls. (A. Campbell Neil, 1999: 320-322)


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