(i) Water potential : It is the difference in free energy or chemical potential per unit molal volume of water in a system and that of pure water at the same temperature and pressure.
Factors affecting water potential : It is affected by Solute potential and Pressure potential :
(ii) Plamsolysis occurs when water moves out of the cell and the cell membrane of plant cell shrinks away from its cell wall. This occurs when the cell or tissue is placed in a hypertonic solution.