Water Potential

Water Potential: the measure of the relative tendency of water to move from one area to another, Ψ. – Affected by Osmosis Gravity Surface tension Pressure

Water Potential = Pressure potential + Solute potential Ψ = Ψ p + Ψ s Pure water: 0 = The addition of solutes to water, lowers the water potential (hypertonic solution has less potential than a hypotonic solution) – Makes water potential more negative Increase in water pressure, increases the water potential – Makes water potential more positive Water will move from an area of high water potential to an area of lower water potential.

Pressure potential: mechanical or physical pressure that is present when water exerts an outward force, typically on the cell wall – Proportional As pressure increases, water potential increases

Solute potential: the effect that solutes have on the solutions overall water potential. – Inversely proportional As solute increases, water potential decreases