What are Plasmolysis and Deplasmolysis?
|Plasmolysis- When a plant cell is placed in hypotonic solution water accumulates due to endosmosis. It swells up but does not burst because it is surrounded by a rigid cell wall, which can withstand the turgor pressure exerted by distended cell contents. The plant cell in this condition is called turgid.|
When placed in a hypertonic solution, the cytoplasm of plant cell shrinks and its plasma membrane separates from the cell wall due to exosmosis. The vacuole also shrinks. The cell in this condition is called plasmolysed and this phenomenon is plasmolysis.
Deplasmolysis- It is the swelling of plasmolysed protoplasm so as to come in contact with the cell wall and regain its original volume. Deplasmolysis can occur only if the freshly plasmolysed tissue is immediately placed in hypotonic solution or pure water.
Importance of Plasmolysis:
|(1) The technique of plasmolysis is used for the preservation of pickles, jams, meat, fish and some dry fruits by using excess salt or sugar. The latter does not allow the germination of microbes.|
(2) By salting tennis lawns, weeds can be killed due to permanent plasmolysis of the cells. For this hypertonic salt solution is used.
(3) It is used to determine the osmotic pressure of the cells.
(4) The phenomenon of plasmolysis and deplasmolysis indicates that the cells function as osmotic systems.
(5) A high concentration of chemical fertilizers should be avoided as it damages the crop by exosmosis of water from the cells of roots.
(6) Salting checks the growth of plants in wall cracks.
(7) It occurs in living cells.
(8) Plasmolysis shows that plasma membrane acts as a semipermeable membrane.