The fundamental concept of understanding the movement of water is called water potential. Water molecules possess kinetic energy and the greater the concentration of water greater the kinetic energy. This kinetic energy with which the movement of water takes place is called water potential. It is represented by the Greek symbol Psi or ψ _w and is expressed in Pascals (pa). The factors affecting water potential is solute potential and pressure potential. The solute potential is the magnitude of lowering the water potential due to dissolution of solute in pure water it is represented by ψ _s and it is always negative. The pressure potential is a pressure greater than the atmospheric pressure applied to pure water it is represented as ψ _p and it is usually positive.