Water moves across a selectively permeable membrane from higher water potential to lower by
Water potential (MegaPascal, or Ψ) is the sum of
pressure potential (ΨP) and solute potential (ΨS):
Ψ = ΨP + ΨS.
- The addition of solutes reduces water potential (to a negative value).
- Application of physical pressure increases water potential.
- The increased physical pressure can reverse the effects of the solutes .
- A negative pressure reduces water potential (on the other side).