When a plant cell is placed in a hypertonic solution, water moves out of the cell by a process known as osmosis. Osmosis is the movement of water across a semipermeable membrane from an area of lower solute concentration to an area of higher solute concentration. In a hypertonic solution, the concentration of solutes outside the cell is greater than that inside the cell.
As water leaves the plant cell, the protoplast, which is the living part of the cell including the cytoplasm and organelles, begins to shrink away from the rigid cell wall. This phenomenon is known as plasmolysis. The cell wall remains intact, but the shrinkage of the protoplast can affect the cell’s overall function and health. If a plant experiences prolonged plasmolysis, it can lead to wilting and, ultimately, damage to the plant. This response of plant cells highlights the importance of maintaining proper water balance for cellular health and plant vitality.