Water Movement Driven by Water Potential Gradient

Steps:

• Water potential (ψ) in the solution is less negative than inside the cells, meaning external ψ > internal ψ.
• Water diffuses from higher ψ (solution) to lower ψ (cells) via osmosis.
• Plant cells absorb water, increasing internal pressure against the rigid cell wall.
• After 20 minutes, cells reach full swelling without damage.

Why C is correct:

• Turgid describes plant cells swollen and firm from water influx in a hypotonic solution (external ψ higher than internal).

Why the others are wrong:

• A. Burst: Plant cell walls prevent bursting in hypotonic conditions; this occurs in animal cells.
• B. Incipient plasmolysis: Initial stage of water loss in hypertonic solutions (external ψ lower).
• D. Plasmolysed: Cells shrunken with plasma membrane pulled from wall due to water efflux in hypertonic solutions.

Final answer: C