Question

Is plasmolysis always reversible? Thank you!

Answer 1

Plasmolysis is generally reversible.

Explanation:

Plasmolysis is contraction of protoplasm due to ex-osmosis.

When a living cell is placed in hyper-tonic solution, water from the cell sap moves into the external medium, as the concentration of solute is higher in external medium as compared to that in cell sap (hyper-tonic solution).

The protoplasm contracts due to ex-osmosis. This contraction of the protoplasm as a consequence of ex-osmosis is termed plasmolysis.

When a plasmolyzed cell is placed in pure water (hypotonic solution), endosmosis occurs and the protoplasm comes back to its original position. This is termed as deplasmolysis.

Plasmolysis is thus reversed by placing the plasmolyzed cell in hypotonic solution.

Here is a video which describes how osmosis impacts onion cells placed into tap water and then into a salt water solution.

Hope this helps!