Water Potential

High Water Potential: more water, more free energy

Low Water Potential: less water, less free energy

Equation: Water potential (Ψ) = pressure potential (Ψp) + solute potential (Ψs)

Solute/Osmotic Potential

Equation: Ψs= iCRT

i = ionization constant

• sugars: i = 1, NaCl: i = 2

C = Molarity of Solution (M = moles of solute/ liters of solution)

R = gas pressure constant → 0.0831 liter bars / moles Kelvin

T = temperature in Kelvin (K = 273+ °C)

Pressure Potential

Open System: Ψp = 0

Closed System: Ψp = positive value

Tonicity

Hypertonic: high concentration of solute

Hypotonic: low concentration of solute

Isotonic: equal concentration of solute → dynamic equilibrium