Question

Explain all the 3 stages of plasmolysis.

Answer 1

Dear student,
There are three stages in plasmolysis:- a) Limiting plasmolysis b) Incipient plasmolysis c) Evident plasmolysis
When a cell is placed in a hypertonic solution then the cell sap moves out of the cell due to exosmosis due to which the shrinkage of protoplast occurs and it detaches from the cell wall. This is called plasmolysis.

Limiting plasmolysis:- The pressure on the cell wall is simultaneously reduced and the elastic cell contracts causing a reduction in cell size. At this stage, the pressure potential is zero and the osmotic concentration of cell interior is just equivalent to that of external solution. The cell is called flaccid.
Incipient plasmolysis:- Central vacuole shrinks further causing a similar shrinkage of protoplast from the cell wall. Pressure potential becomes negative. Initially the protoplast withdraws itself from the corners.
Evident plasmolysis:- The hypertonic solution now enters the cell in between the protoplast and the cell wall. Due to continued exosmosis, protoplast shrinks further and withdraws from the cell wall except at one or a few places.

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