Briefly describe water potential. What are the factors affecting it?
Water potential: Free energy per mole of water molecule is called water potential. It is represented by Greek letter ‘φ’ (Psi). Water potential of pure water is zero and addition of solute, decreases its free energy or water “‘potential. Factors affecting water potential are as following: (i) Matric potential (φm) causes by adsorbent or colloidal particles (always negative and almost negligible). (ii) Solute potential (φs) caused by presence of solute particles (decreases the water potential). (iii) Pressure potential (φp) caused by entry or exit of water (increases the water potential). φw= φp + φs + φm