Explanation

Cohesion-tension theory for ascent of sap was originally proposed by Dixon and Jolly (1894) and greatly supported and elaborated by Dixon (1914, 1924). It is also called transpiration pull theory and is based on the assumptions of: Continuous water column from rot hairs to the tip of the plant. Cohesive and adhesive properties of water molecules. Strong transpiration pull exerted by all the transpiring leaves on the stem.