Question

Water rises in the stem due to

• A. Cohesion and transpiration pull
• B. Turgor pressure
• C. Osmotic pressure
• D. None of the above

Answer 1

Answer: (A)

Cohesion and transpiration pull

In plants, water rises in the stem through xylem elements.

Water rises due to the phenomenon of cohesion and transpiration pull theory given by Dixon and Joly. It is the widely accepted theory for the ascent of water or plant sap. Cohesion is the property of molecules of the same substance to remain together. and during transpiration when there is a scarcity of water in the aerial region then transpiration pull occurs.

Thus due to cohesion between water molecules and transpiration pull, water rises upwards in the stem.

So the correct answer is 'Cohesion and transpirational pull'.