Osmosis: Definition, Types and Significance | Plant Physiology

In this article, we will discuss about:- 1. What is Osmosis? 2.Types of Osmosis 3. Osmotic Solutions and 4. Significance of Osmosis

1. What is Osmosis?

Diffusion of water from its pure state or dilute solution into a solution or stronger solution when the two are separated by a semipermeable membrane is termed as osmosis.

2.Types of Osmosis

Osmosis is of two types:

(i) Endosmosis: When a substance is placed in a hypotonic solution, the solvent molecules move inside the cell and the cell becomes turgid or de-plasmolyzes. This is known as endosmosis.

(ii) Exosmosis: When a substance is placed in a hypertonic solution, the solvent molecules move outside the cell and the cell becomes flaccid or plasmolyzes. This is known as exosmosis.

3. Osmotic Solutions

There are three different types of solutions:

1. An isotonic solution is one that has the same concentration of solutes both inside and outside the cell.
2. A hypertonic solution is one that has a higher solute concentration outside the cell than inside.
3. A hypotonic solution is the one that has a higher solute concentration inside the cell than outside.

4. Significance of Osmosis

• Osmosis influences the transport of nutrients and the release of metabolic waste products.
• It is responsible for the absorption of water from the soil and conducting it to the upper parts of the plant through the xylem.
• It stabilizes the internal environment of a living organism by maintaining the balance between water and intercellular fluid levels.
• It maintains the turgidity of cells.
• It is a process by which plants maintain their water content despite the constant water loss due to transpiration.
• This process controls the cell to cell diffusion of water.
• Osmosis induces cell turgor which regulates the movement of plants and plant parts.
• Osmosis also controls the dehiscence of fruits and sporangia.
• Higher osmotic pressure protects the plants against drought injury.