Question

The rupture or fractionation do not usually occur in the water coloumn in vessels / tracheids during the ascent of sap because of

• A. lignified thick walls
• B. cohesion and adhesion
• C. weak gravitational pull
• D. transpiration pull

Answer 1

The correct option is B cohesion and adhesion

The rupture or fractionation do not usually occur in the water column in vessels/ tracheids during the ascent of sap because of cohesion and adhesion. This is because continuity of water column is maintained by cohesion and adhesion. The conduction of water from root to aerial parts of plants is called ascent of sap. The water molecules remain attached to each other by cohesion force. The magnitude of this force is very high. This helps in the continuous water column in the xylem. The adhesive force is present between the water molecules and the walls of xylem. This also helps in continuous water column in the xylem.

Thus, the correct answer is option B.