Water Rise Without Transpiration

Steps:

• Shoot removal stops transpiration, eliminating pull from leaf evaporation.
• Root pressure from active transport in roots pushes water upward into xylem.
• Capillary action in narrow xylem vessels draws water by adhesion and cohesion.
• Combined root pressure and capillarity enable water ascent in decapitated plants.

Why B is correct:

• In plants without shoots, root pressure (osmotic force generating positive pressure) and capillary action (surface tension in vessels) drive water rise, as observed in guttation.

Why the others are wrong:

• A includes transpiration pull, which requires intact leaves and evaporation.
• C includes transpiration pull, absent without shoots.
• D omits capillary action, which supplements root pressure in xylem.

Final answer: B