In plants, the water is lost in the form of water vapour from the stomata of the leaves. As the film of water is continuous over the cells, thus a transpirational pull is generated by the loss of water from the stomatal pores of leaves. This is called the cohesion-tension model of water transport. During daytime, the water lost through transpiration by the leaves to the surroundings causes the guard cells and other epidermal cells to become flaccid.
They, in turn, take water from the xylem. This creates a negative pressure or tension in the xylem vessels, from the surfaces of the leaves to the tips of the roots, through the stem. As a result, the water present in the xylem is pulled as a single column from the stem. Linica Uday.
Oct 22, Explanation: Osmosis is a vital process in biological systems as biological membranes are semi-permeable. Related questions How can osmosis be used in real life? How can osmosis affect a cell? Why is osmosis a unique form of diffusion? What are some examples of osmosis? What is osmosis? If the solution is hypertonic, the cells will lose water and shrink plasmolyze.
If the solution is hypotonic or if pure solvent is used the cells will swell; the osmotic pressure that is developed may even be great enough to rupture the cell membrane. Saltwater from the ocean is hypertonic to the cells of the human body; the drinking of ocean water dehydrates body tissues instead of quenching thirst.
In plants osmosis is at least partially responsible for the absorption of soil water by root hairs and for the elevation of the liquid to the leaves of the plant. However, plants wilt when watered with saltwater or treated with too much fertilizer, since the soil around their roots then becomes hypertonic.
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