Question

Which of the following seeds will show more imbibition pressure?
A. Sesame seeds
B. Gram seeds
C. Wheat seeds
D. Rice seeds

Answer 1

Hint: The process by which a substance immersed in a liquid or water swells up in volume without disintegrating itself is called imbibition. It is a kind of diffusion. In this process a solution is not formed. The solid substance is called an imbibant while the liquid is called an imbibate.

Complete answer:
The solid particles undergoing imbibition are called colloids. All colloids are hydrophilic in nature, that is they are attracted towards water. Thus, an adsorbent will hold the imbibate due to an attractive force between the two. Imbibate creates a pressure called an imbibition pressure inside the imbibant. Imbibition is affected by various factors like pressure, texture of imbibant and also the pH of the medium. If the water potential of an imbibant is negative and this dry imbibant comes in contact with an imbibate, diffusion occurs. Imbibe like water having a higher potential will move into the imbibant till an equilibrium is reached. This process will release heat which is also called heat of wetting.
All biomolecules, like proteins, carbohydrates, starch, cellulose and fats will imbibe water. But the imbibition capacity will differ in each biomolecule. Proteins will have the greatest imbibition capacity because they are hydrophilic in nature. This is followed by carbohydrates and starch and then by cellulose. Fats have the least capacity for imbibition as they are hydrophobic in nature.
So, a proteinous gram seed will show maximum imbibition pressure compared to the other given seeds.

Therefore, the correct answer is option (B), Gram seeds.

Note:
Imbibition facilitates water absorption thereby helping in germination of seeds by the rupture of testa. It can occur both in living as well as in dead cells and is a reversible process. It increases with an increase in temperature.