What is the function of the stigma in the pistil?

The correct answer is Option (3) → Reception of pollen grains

The pistil is the female part of the flower. It has three parts: the stigma at the top, the slender style below it and the swollen ovary at the base. Each part has its own job in reproduction.

Option (1) Production of pollen grains — Incorrect. Pollen grains are made inside the anther, which is part of the stamen (the male part of the flower). The pistil does not make pollen.

Option (2) Protection of the ovary — Incorrect. The ovary lies at the base of the pistil and holds the ovules. The stigma sits at the top of the style, far from the ovary, so its job is not to protect the ovary.

Option (3) Reception of pollen grains — Correct. The stigma is the part on which pollen grains land during pollination. It receives the pollen, and the pollen grain then germinates on it to form a pollen tube.

Option (4) Formation of the embryo sac — Incorrect. The embryo sac (female gametophyte) forms inside the ovule, from a functional megaspore. The stigma has no role in forming it.

NCERT Extract:
The Pistil, Megasporangium (Ovule) and Embryo Sac – “… Each pistil has three parts (Figure 1.7a), the stigma, style and ovary. The stigma serves as a landing platform for pollen grains. The style is the elongated slender part beneath the stigma. The basal bulged part of the pistil is the ovary. Inside the ovary is the ovarian cavity (locule). The placenta is located inside the ovarian cavity.”