Q.51 Which one or more of the following statements is/are NOT CORRECT with
respect to pollen development in angiosperm?
(A) Tapetal cell wall in all angiosperms breaks down to release the cytoplasmic
content.
(B) Tapetal cell wall in all angiosperms remains intact.
(C) Tapetal cell wall breaks down in some angiosperm species, whereas it remains
intact in others.
(D) Within an angiosperm species, the tapetal cell wall breaks down in some
individuals and not in others.

Options (A), (B), and (D) are NOT correct.

Explanation of Options

The tapetum, a nutritive layer in the angiosperm anther, exists in two primary types: secretory (glandular), where cell walls remain intact and release contents via secretion or degeneration without wall breakdown, and periplasmodial (amoeboid), where cell walls break down, allowing protoplasts to form a multinucleate periplasmodium. This variation occurs across angiosperm species but is consistent within each species.​

• Option (A): Incorrect, as tapetal cell walls do not break down in all angiosperms; secretory types keep walls intact.​

• Option (B): Incorrect, as walls break down in periplasmodial types found in some angiosperms.​

• Option (C): Correct, accurately describing the species-specific variation between secretory and plasmodial tapeta.​

• Option (D): Incorrect, as tapetum type is genetically fixed within a species, showing no individual variation.​

Pollen development in angiosperms relies on the tapetum, a key anther layer providing nutrients and pollen wall precursors. During microsporogenesis, tapetal cells nourish pollen mother cells and microspores through secretion or degeneration.​

Tapetum Types

Two main types exist based on cell wall behavior:

• Secretory (glandular) tapetum: Walls stay intact; contents release via glandular secretion. Common in many angiosperms.​

• Periplasmodial (amoeboid) tapetum: Walls dissolve, protoplasts fuse into a multinucleate mass invading the locule.​

This species-level difference supports microspore release and pollen maturation.​

Role in Pollen Development

Tapetum secretes enzymes like callase for callose wall degradation and sporopollenin for exine formation. Degeneration via programmed cell death supplies lipids and proteins. Disruptions cause male sterility.​

Exam Relevance

For CSIR NET, recognize that tapetal cell wall breakdown varies by species, not universally or individually.​