Read the passage and answer the following questions:
A typical microsporangium, when observed in a transverse section, has a nearly circular shape. It is typically surrounded by four layers of walls: the epidermis, endothecium, middle layers, and the tapetum. The outer three wall layers serve to protect the microsporangium and aid in the anther's opening to release the pollen. The innermost wall layer, known as the tapetum, provides nourishment to the developing pollen grains. Tapetum cells are characterized by their dense cytoplasm and often contain multiple nuclei. In angiosperms, an anther usually consists of two lobes, each with two theca, making it dithecous. The theca are often separated by a longitudinal groove. The anther itself has a tetragonal shape with four microsporangia situated at its corners, two in each lobe. These microsporangia undergo further development and transform into pollen sacs.
What does a pollen grain represent?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → Male gametophyte.
The pollen grain develops from a microspore and later produces the male gametes, so it is the male gametophyte.
Option (1) Male gamete. — Incorrect. A male gamete is formed inside the pollen grain, when the generative cell divides. The pollen grain itself is the gametophyte that produces the gametes.
Option (2) Ovum. — Incorrect. The ovum (egg cell) is the female gamete. It lies in the egg apparatus of the embryo sac.
Option (3) Male gametophyte. — Correct. The pollen grains represent the male gametophytes.
Option (4) Female gametophyte. — Incorrect. The female gametophyte is the embryo sac, which develops from the functional megaspore inside the ovule.
NCERT Extract:
Stamen, Microsporangium and Pollen Grain – “… Inside each microsporangium several thousands of microspores or pollen grains are formed that are released with the dehiscence of anther (Figure 1.3c). Pollen grain: The pollen grains represent the male gametophytes.”
The Pistil, Megasporangium (Ovule) and Embryo Sac – “… Cells of the nucellus have abundant reserve food materials. Located in the nucellus is the embryo sac or female gametophyte.”