Osmosis - Plasmolysis & Deplasmolysis in plant cells

1) Plasmolysis?

When plant cells are immersed in hypertonic solution, water molecules diffuse out of the plant cells (the vacuoles) by osmosis. The cells shrinks (plasmolysis) because vacuole & cytoplasm lose water, and plasma membrane pulls away from the cell wall. The plant cells become flaccid, the plant wilts and this could lead to death.
Eg: when plant is not receiving water supply for long period of time, or excessive fertilisers are given to the plant, etc.

In the video below, you will get the same result when the salt solution is replaced by excessive use of fertilisers (at high concentration).



2) Deplasmolysis?

When a plasmolysed plant cell is immersed in hypotonic solution (eg: distilled water), the plant cell becomes turgid again due to uptake of water molecules into plant cell by osmosis.