Question

Which of the following contributes most to transport of water from the ground to the leaves of a tall tree?

• A. Breakdown of ATP
• B. Cohesion of water and transpiration pull
• C. Root pressure
• D. Capillary rise of water in xylem

Answer 1

Answer: (B)

Cohesion of water and transpiration pull

For small plants root pressure and transpirational pull synergistically facilitate water transport from roots to leaves. However, in the case of tall trees like pine, cedar etc, the root pressure is too small to do the same. Here the cohesive forces of water molecules help in building high surface tension and thus transports the water against gravitational pull to great heights.
So, the correct answer is option B.