The term plasmolysis is derived from the Latin word ‘plasma’ meaning ‘matrix’ and the Greek word ‘lysis’, meaning ‘loosening’.
When Does It Occur
What Happens in Plasmolysis: Its Process
Stages of Plasmolysis in Plant Cell
Types of Plasmolysis
Do Cells Recover from the State of Plasmolysis
Its Importance
Examples in Daily Life
When a cell is exposed to a hypertonic solution, water starts to flow down its concentration gradient. It thus moves from a region of low solute concentration inside the cell to the high solute concentration in the extracellular fluid. The net water movement across the plasma membrane through osmosis causes the plant cell wall to lose its turgor pressure. Finally, it causes the central vacuole and the cytoplasm (together known as protoplast) to detach from the cell wall, and the cell is said to be in plasmolyzed state. After plasmolysis, the size of the protoplast gets reduced. Simultaneously the pressure on the cell wall decreases, causing it to contract and reduce in size. At times, if water is lost severely, the cell walls may collapse, which results in the death of the cell. When a cell is exposed to an isotonic solution, it loses its turgor pressure. At this stage, although the cell does not get plasmolyzed, it is not turgid either. As a result, the green parts of the plant droop and cannot hold the leaves up in the sunlight. Plasmolysis hardly happens in nature. Instead, it is induced in the laboratory by immersing living cells in strong saline or sugar solutions to undergo exosmosis. Generally, the cells of Tradescantia or Rheo plant, Elodea plants, or onion epidermal cells are used for this experiment. The reason is that they have colored sap, making them easily observable and identifiable under the microscope. During deplasmolysis, water again passively diffuses into the protoplast, i.e., the central vacuole and cytoplasm. As a result, the protoplast swells up. Initially, it comes in contact with the cell wall and then develops the turgor pressure.
