What is the function of the tapetum in the microsporangium?

The correct answer is Option (2) → Nourishment of pollen grains

The wall of a microsporangium has four layers: epidermis, endothecium, middle layers and tapetum. The outer three layers protect the microsporangium and help the anther burst open (dehisce) to release pollen. The innermost layer, the tapetum, feeds the developing pollen grains. Its cells have dense cytoplasm and often more than one nucleus.

Option (1) Protection — Incorrect. Protection is the job of the outer three wall layers: epidermis, endothecium and middle layers. The tapetum lies on the inner side.

Option (2) Nourishment of pollen grains — Correct. The tapetum is in direct contact with the sporogenous tissue and the developing pollen. It nourishes the developing pollen grains.

Option (3) Dehiscence — Incorrect. Dehiscence (bursting of the anther to release pollen) is helped by the outer three wall layers, not by the tapetum.

Option (4) Formation of sporogenous tissue — Incorrect. The sporogenous tissue is already present at the centre of the young anther. The tapetum surrounds it; it does not form it.

NCERT Extract:
Stamen, Microsporangium and Pollen Grain – “… Structure of microsporangium: In a transverse section, a typical microsporangium appears near circular in outline. It is generally surrounded by four wall layers …– the epidermis, endothecium, middle layers and the tapetum. The outer three wall layers perform the function of protection and help in dehiscence of anther to release the pollen. The innermost wall layer is the tapetum. It nourishes the developing pollen grains.”