Question

Intine of the pollen grain is made up of:

• A. Starch and agarose
• B. Heparin and lignin
• C. Cellulose and pectin
• D. Glycogen and collagen

Hint:

Pollen Grain Wall Layers:
$\bullet$ Exine: Outer, thick, sculpted layer made of sporopollenin.
$\bullet$ Intine: Inner, thin, continuous layer made of cellulose and pectin.

Answer 1

The Correct Option is C

Concept:
The microspore or pollen grain wall (sporoderm) in angiosperms has a two-layered protective wall architecture: an outer exine and an inner intine.

Step 1: Biochemical Composition of Pollen Wall Layers:
- Exine (Outer Wall): Composed of sporopollenin, one of the most resistant organic biopolymers known, which resists degradation by high temperatures, strong acids, alkalis, and enzymes. It exhibits apertures called germ pores where sporopollenin is absent.
- Intine (Inner Wall): The thin, continuous, flexible inner layer situated beneath the exine. It is composed biochemically of cellulose and pectin (pectocellulosic in nature). During pollen germination, the pollen tube emerges as an extension of the intine through a germ pore.

Step 2: Evaluating the Given Options:
- Option (A) Starch and agarose: Incorrect, agarose is derived from red seaweed.
- Option (B) Heparin and lignin: Incorrect, heparin is an animal anticoagulant.
- Option (C) Cellulose and pectin: Correct chemical composition of intine.
- Option (D) Glycogen and collagen: Incorrect, these are animal storage and structural macromolecules.

Step 3: Final Answer:
Thus, the intine of the pollen grain is made up of Cellulose and pectin (Option C).