Osmosis and water potential gradients in plant cells

Steps:

• Identical cells start with the same initial water potential (ψ_cell).
• Sugar solutions have decreasing ψ with increasing concentration: ψ_2.5% > ψ_5% > ψ_10% (from least to most negative).
• Plasmolysis occurs when ψ_solution < ψ_cell, causing water exit (hypertonic, 10% solution for cell Z).
• No net movement when ψ_solution = ψ_cell (isotonic, 5% for cell X); turgor when ψ_solution > ψ_cell (hypotonic, 2.5% for cell Y).

Why D is correct:

• For plasmolysed cell Z in 10% solution, ψ_cell > ψ_solution (cell less negative than solution), so D falsely claims the opposite.

Why the others are wrong:

• A is correct: cell X in isotonic 5% solution matches ψ_cell = ψ_solution.
• B is correct: cell Y in 2.5% solution shows no plasmolysis (statement misphrased but aligns with observation of turgor).
• C is correct: cell in 2.5% solution (likely Y) matches the hypotonic observation.

Final answer: D