Question

The rupture and fractionation do not usually occur in the water column in vessel/tracheids during the ascent of sap because of :

• A. Weak gravitational pull
• B. Transpiration pull
• C. Lignified thick walls
• D. Cohesion and adhesion

Answer 1

The correct option is D

Cohesion and adhesion

Water molecules remain attached to one another by a strong mutual force of attraction called cohesion force. On account of this force, the water column can bear a tension or pull of upto 100 atm. Also, the water column does not break its connection from the tracheary elements (vessels and tracheids) because of adhesion force between their walls and water molecules.