In angiosperms during microsporogenesis, meiosis occurs in:

The correct answer is Option (1) → Microspore mother cells

Option (1) Microspore mother cells — Correct. Each microspore mother cell undergoes meiosis and forms a tetrad of microspores.

Option (2) Endothecium — Incorrect. The endothecium is a wall layer of the anther.

Option (3) Pollen grains — Incorrect. Pollen grains form after meiosis; they divide by mitosis.

Option (4) Tapetum — Incorrect. The tapetum is the innermost wall layer that nourishes the pollen.

NCERT Extract:
Stamen, Microsporangium and Pollen Grain – “… When the anther is young, a group of compactly arranged homogenous cells called the sporogenous tissue occupies the centre of each microsporangium. Microsporogenesis : As the anther develops, the cells of the sporogenous tissue undergo meiotic divisions to form microspore tetrads.”