Question

What is limiting, incipient, evident plasmolysis? Give differences between them. Explain.

Answer 1

Hint: Plasmolysis is a standard response of plant cells subjected to hyperosmotic stress. The loss of turgor produces the vicious detachment of the living protoplast from the cell wall. The plasmolytic process is mainly led by the vacuole. Plasmolysis is reversible (deplasmolysis) and typical to living plant cells.

Complete step-by-step answer:
Plasmolysis is described as the process of shrinkage or contraction of the protoplasm of plant cells and is caused by the loss of water in the cell. Plasmolysis is an example of the outcomes of osmosis and rarely takes place in nature. The word Plasmolysis was derived from the Greek and Latin word plasma (The mould and lysis which means loosening).At zero turgor pressure, osmotic potential equivalent to its water potential and limiting plasmolysis has been detected. Pressure potential is always zero at limiting plasmolysis. The turgor pressure is high in the turgid cell. Limiting plasmolysis is the pressure potential that is zero and the osmotic concentration of the cell interior is just equal to that of the external solution (isotonic).

Phases of Plasmolysis:The entire process of Plasmolysis occurs in three different phases:
Incipient plasmolysis:It is the preliminary phase of the plasmolysis, during which water begins to flow out of the cell; initially, the cell shrinks in volume, and the cell wall becomes noticeable.
Evident plasmolysis:It is the next phase of the plasmolysis, during which, the cell wall has achieved its limit of contraction, and the cytoplasm gets separated from the cell wall to attain the spherical form.
Final plasmolysis:It is the third and final phase of the plasmolysis, during which the cytoplasm will be entirely free from the cell wall and continues in the centre of the cell.



Note: As the cell wall contracts, the shape is modified. This is Plasmolysis and takes place in the state of hypertonic states. A good example of plasmolysis is the contraction of vegetables when kept in a hypertonic medium.