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Water potential in plants is composed of two separate forces. The first is the o

ID: 163856 • Letter: W

Question

Water potential in plants is composed of two separate forces. The first is the osmotic potential (also called the solute potential) that causes water to move down its own concentration gradient. The second is the pressure potential, or a mechanical pressure, exerted by the cell wall onto the water inside the cell. Answer the following questions about these two forces.

In which of the two cells below will the solute potential be the most negative? Why? (Note that the blue dots represent solutes).

Explanation / Answer

OSMOTIC POTENTIAL: Osmotic potential is the decrease in chemical potential in pure water due to presence of solute particles in it.Osmotic pressure and osmotic values are numerically equal but osmotic pressure has positive sign and osmotic potential always carries a negative sign.

PRESSURE POTENTIAL: The component of water potential due to the hydrostatic pressure that is exerted on water in a cell. In turgid plant cells it usually has a positive value as the entry of water causes the protoplast to push against the cell wall.

The blue dots in which higher in number in the cells have solute potential be the most negative.

The value of osmotic potential or solute potential are carried by a formula

s = CxRxT