Question

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.

Hint:

Mnemonic: {Se}cretory tapetum = {Se}aled walls; {A}moeboid = {A}bsent walls (plasmodium). Tapetal behavior is species-specific.

Answer 1

The Correct Option is A, B, D

Step 1: Role and position of the tapetum. The tapetum is the innermost nutritive layer of the anther wall that surrounds the developing microspore tetrads and free microspores. It supplies precursors for the pollen wall (sporopollenin, tryphine), enzymes for callose dissolution, proteins, and lipids essential for pollen maturation. How the tapetal cell wall behaves (remains intact vs breaks down) determines how these materials are delivered.
Step 2: Two major tapetal types across angiosperms.
\(\bullet\) Secretory (glandular) tapetum: Tapetal cells stay in place with intact cell walls. They secrete materials apoplastically into the locule. Common in many dicots and monocots.
\(\bullet\) Amoeboid/Periplasmodial tapetum: Tapetal cell walls break down early; the protoplasts fuse to form a multinucleate periplasmodium that bathes the microspores and transfers materials symplastically. Found in a distinct set of taxa.
These are species-level traits. Within a given species the tapetum type is genetically fixed and consistent under normal development.
Step 3: Evaluate each statement.
(A) “Tapetal cell wall in all angiosperms breaks down …” — Not correct. Secretory tapeta retain walls; only amoeboid types break down.
(B) “Tapetal cell wall in all angiosperms remains intact.” — Not correct. Amoeboid/periplasmodial types contradict this.
(C) “Breaks down in some species, intact in others.” — Correct. This exactly captures the distribution of amoeboid vs secretory tapeta across species.
(D) “Within a species it breaks down in some individuals and not in others.” — Not correct. Tapetal type is a stable developmental feature of the species (barring pathological male-sterile mutants or experimental perturbations).
% Takeaway (why exams love this) Key takeaway: The falsehoods are the universal claims in (A) and (B) and the intraspecific variability claim in (D). Hence, the NOT CORRECT options are (A), (B), and (D).