Class XI Practical: Physiology - Demonstration of Plasmolysis (Rhoeo Leaf/Onion Bulb)

Objective

To observe the phenomenon of plasmolysis in plant cells when exposed to a hypertonic solution.

Guidelines

1. Sample Preparation: Obtain a thin epidermal peel from a Rhoeo leaf or an onion bulb scale.
2. Mounting: Mount a small piece of the peel in a drop of distilled water on a clean slide and observe under a compound microscope to see normal turgid cells.
3. Inducing Plasmolysis: Replace the distilled water with a hypertonic solution (e.g., 5% or 10% NaCl or sucrose solution) by adding it to one side of the coverslip and drawing it under with a piece of filter paper from the opposite side.
4. Observation: Observe the cells under the microscope. Note the changes in the protoplast (cell membrane pulling away from the cell wall) as water leaves the cell.
5. Deplasmolysis (Optional): Replace the hypertonic solution with distilled water and observe the recovery of the cells.

Expected Outcome

Clear microscopic observation of plasmolysed cells, where the protoplast shrinks and detaches from the cell wall, illustrating the effect of osmosis in plant cells.