Plasmolysis Definition

Plasmolysis is the process in which cells lose water in a hypertonic solution. The reverse process, deplasmolysis or cytolysis, can occur if the cell is in a hypotonic solution resulting in a lower external osmotic pressure and a net flow of water into the cell.

What is Plasmolysis?

Plasmolysis can be divided into two words, where plasma means matrix and lysis means loosening. The desiccation of the cell’s protoplast due to loss of water, which occurs at a distance from the plant, is called as Plasmolysis.

Thus, voids are seen between the plasma membrane and the cell wall. Convex and concave are the two plasmolysis types.

Shrinking of protoplasm whereas, concave pockets are formed by plasma membrane in concave plasmolysis, however there exist common places between the protoplasm and cell wall. With hypotonic solution, the situation can be reversed for concave plasmolysis.

From the cell wall, protoplast has separated itself and the cell is now of spherical shape and this convex protoplast, which cannot be reversed.

Crenation is seen in animals, which is nothing but plasmolysis, and the cells are contracted, however plants does not contract because of the cell wall, thus possess concave pockets or are circular.

Plasmolysis vs Cytolysis

Plasmolysis and cytolysis are separate as the cell ruptures due to the amount of water present in the cell, more than the cell can hold and this happens when the cell comes in contact with a hypotonic solution and the water keeps on entering the cell more than the limit of the cell, resulting in cytolysis. This is seen in red blood cell, which explodes but does not happen in plants as they turgor pressure and cell wall.

Due to variation in osmotic pressure and movement plasmolysis and cytolysis occurs. In plasmolysis water exits from the cell due to hypertonic environment, whereas in cytolysis water moves inside due to hypotonic conditions. Thus, they are the opposite of each other.

Plasmolysis vs Turgidity

Due to variation in osmotic concentration of solutes in the solution and movement plasmolysis and turgidity occurs. In plasmolysis, the water is thrown out of the cell, whereas in turgidity, there is influx of water. Thus, contraction of cell takes place due to plasma membrane and protoplasm gets isolated from cell wall and the opposite of this occurs in turgidity.

Turgidity takes place when cell is placed in hypotonic solution and plasmolysis occurs when there is hypertonic condition. Thus, turgor pressure elevates in turgidity and drops in plasmolysis. Thus, the plants in turgidity stands straight and bend down in plasmolysis.

Plasmolysis vs Flaccidity

In plasmolysis, the water is thrown out of the cell, due to hypertonic environment. Thus, contraction of cell takes place where, plasma membrane and protoplasm gets isolated from cell wall. Due to absence of water between the plant and the surrounding, turgor is lost, thus flaccidity occurs. Such a cell is neither contracted nor expanded.

However, these processes quite resemble each other as water is lost and they start to bend down which is the plant. Both these conditions can be normalized once the cell is near the hypotonic environment.

Plasmolysis Process

Appropriate solute concentration and pressure in the plant is maintained by the vacuole, whose work is osmoregulation. Water diffuses into the cell when there is variation in solute or water concentration. The movement of water from a region of high water to a region of low water is called as Osmosis. Water will always move to a region which has a greater number of solutes, when referring to solute.

Turgor pressure can be kept under control if salt and water amount is maintained. To maintain the structure of plants, water molecules possess pressure which will move them towards the plant cell, thus maintain structure.

Thus, plant turgidity is very vital, as it limits the water amount and takes up only the required amount of water and if this turgor pressure is imbalanced or damaged then the plant will not be able to stand through in isotonic environment, which means when the concentration of solute within the environment and the cell is similar.

Such a cell is called plasmolyzed and is no more turgid and can be called as a flaccid cell. Hypertonic is those that has more salt than water, and in such a hypertonic condition, cell will release water and this process is plasmolysis and the cell is in plasmolyzed condition.

However, this process can be over turned by de-plasmolysis and if the water is effluxed continuously it would lead to cytorrhysis, where the wall of the cell is disintegrated. Plasmolysis is performed in lab when cells ae exposed to sugar or salt in high concentration. However, this process does not happen in the environment.

Concave vs Cconvex Plasmolysis

The desiccation of the cell’s protoplast due to loss of water, which occurs at a distance from the plant, is called as Plasmolysis. Thus, voids are seen between the plasma membrane and the cell wall. Convex and concave are the two plasmolysis types.

From the cell wall, protoplast has separated itself and the cell is now of spherical shape and this convex protoplast, which cannot be reversed. Plants produce wax and control stomata so that water is not released.

Plasmolysis Examples

Plasmolysis is performed in lab where cells are exposed to sugar or salt in high concentration. However, this process does not happen in the environment. However, some examples are flooding of coastal areas with elevated salt content and when they are left unprotected to chemicals such as weedicides.

Plasmolysis Importance

In plasmolysis, the water is thrown out of the cell, due to hypertonic environment. Thus, contraction of cell takes place where, plasma membrane and protoplasm gets isolated from cell wall. Voids are seen between the plasma membrane and the cell wall.

From the cell wall, protoplast has separated itself and will signal the plant to start absorbing water and stop further loss of water, which is the backup plan of plasmolysis until cytorrhysis has arrived, which will eventually disintegrate the cell wall and finally apoptosis.