Question

Physical force theory explains

• A. Non-living cells are not essential for ascent of sap.
• B. Living cells are not essential for ascent of sap.
• C. Ascent of sap may occur in both living and non-living cells.
• D. Both B and C.

Answer 1

The correct option is B Living cells are not essential for ascent of sap.

Both cohesion, adhesion and transpiration pull that are believed to lift water to great heights in tall trees are physical forces and do not require any plant protein or protoplasm. That is why xylem tracheids and vessels are dead at maturity.