Question

Which of the following is not related with transpiration pull theory?

• A. Capillarity theory
• B. Ascent of sap
• C. Cohesive force
• D. Adhesive force

Answer 1

Answer: (A)

A number of theories have been put forward to explain ascent of sap. Transpiration pull (cohesion) theory is most widely accepted theory. This theory is most widely accepted theory. This theory is based on cohesive force, adhesive force and transpiration pull.
Capillarity theory describes the xylem vessels to behave like the capillary tubes. This capillarity of the vessels and the normal atmospheric pressure are responsible for the ascent of sap. Due to the surface tension of liquid molecules and adhesive forces, the liquid rises up. The finer the tube, the greater will be the rise of water in it. It is associated with water translocation in xylem vessels.