Explanation

Cohesion tension theory or transpiration pull was proposed by Dixon and Jolly. Cohesion force is responsible to produce continuous water column in tracheary elements while the force of adhesion between the cells of tracheary elements and water molecule produce surface tension that accounts for high capillary through tracheary elements. Loss of water from aerial parts through transpiration causes a suction pressure in the water column of plants and this is known as transpiration pull