Question

What are the two components that determine water potential?

Answer 1

Water potential: It is a measure of water molecules that can move in a particular environment or system. It is expressed as Ψ and is measured in kilopascals.
Two components of water potential:

1. Solute potential: It is defined as the amount that the water potential decreases due to the presence of solute in pure water, and is called the osmotic potential or called solute potential. Adding a solute to pure water reduces the free energy of water molecules. The osmotic potential of pure water is zero. That is, it is always less than zero or negative. It is represented by Ψs.
2. Pressure potential: When pressure is greater than the atmospheric pressure in the cell increases the turgor pressure which makes the cell turgid. This is called pressure potential. It is denoted by Ψ_P In the case of plasmolyzed cells, it is zero but can be negative in the xylem vessels of plants.