Question

Ascent of sap is due to which of the following force?

• A. Imbibition
• B. Cellular force
• C. Cohesive force
• D. Atmospheric pressure

Answer 1

Answer: (C)

Cohesive force

According to the most widely accepted theory, the ascent of sap occurs due to the transpiration pull generated due to loss of water from leaves through transpiration. The important aspects of this theory are transpiration which generates the pull and maintenance of a continuous water column in the xylem tracheids and vessels. The continuous water column is maintained with the help of cohesive (attraction between water molecules) and adhesive (attraction forces between water molecules and plant xylem tissue surface) forces.

So, the correct answer is option C.