Physical Concepts of Plant Water Relation - Diffusion

Diffusion is a spontaneous process that leads to net movement of a substance from a region of higher concentration to a region of lower concentration. it can also be defined as the net movement of molecules from region of high free energy to a region of low free energy. The principle of diffusion is of importance in plants because several of the transport processes such as uptake of water and minerals, intake of CO₂ and release of O₂ by leaf cells, loss of water due to transpiration depend in part on diffusion.