Question

Water transport from roots to leaves is explained by

• A. The pressure flow theory
• B. Differences in source and sink solute concentrations
• C. The pumping force of xylem vessels
• D. The cohesion-tension theory.

Answer 1

The correct option is D The cohesion-tension theory.

The cohesion-tension theory explains the translocation of water by the process of transpiration. This theory was proposed by Dixon and Jolly and is popularly known as Cohesion-tension transpiration pull model of water transport. This pull helps in water transport from roots to the leaves. Less than one per cent of water is utilised in photosynthesis and plant growth. Most of the water is lost by transpiration through stomata. Cohesion keeps the water molecules stick together and adhesion allows the water molecules to stick to the xylem walls.

Hence,the correct answer is 'The cohesion-tension theory'.