Question

Which of the following is an example of imbibition ?
A) Uptake of water by root hair
B) Exchange of gases in stomata
C) Swelling of seed when put in soli
D) Opening of stomata

Answer 1

Hint: This is considered to be the first step of water absorption. The classic example seen in our day to day life is changes seen in the wooden doors during the rainy season.

Complete Answer:
- Imbibition is the process of absorption of water by solid particles without formation of a solution.
- In this process, the water moves along its concentration gradient.
- Hence imbibition is regarded as a type of diffusion.
- In this process, the solid particles take in water and thus increase in volume.
- The solid particles that undergo imbibition are known as Imbibants.
- The liquid that is imbibed is known as Imbibate (it is generally water).

The two main factors that favour imbibition are :
a) Concentration gradient.
b) Affinity between Imbibant and Imbibate.

The Examples where Imbibition phenomenon is clearly seen are:
- Seeds swell up as they take water. This helps to rupture the seed coat and thus germination of seeds takes place which results in formation of seedlings and further plants.
- Swelling of dry wood.

Note:
- Imbibition is a reversible process
- Phycocolloids are considered as the best Imbibants.
- Proteins have the best imbibing capacity as compared to starch and cellulose.
- Thus when we soak proteinaceous pea seeds in water, it swells more than wheat seeds.