Explanation

Transpiration, tension, cohesion and adhesion are those factors, which plays an important role in upward movement of xylem sap in plants. Transpiration exerts transpiration pull. Due to cohesion force, water molecules in water column are joined to each other. Adhesion force between the walls of tracheary element and water molecule produce surface tension, which accounts for high capillarity through tracheary elements. While plasmodesmata are bridge-like structures, which join adjacent cells in symplastic movement of water