Answer:
Diploid microspore mother cells divide by meiosis to form four haploid microspores. Each microspore develops into a pollen grain by mitosis.
Step-by-step explanation:
Pollen grains contain the male gametes of a sexually reproducing plant. Pollen grains are haploid cells in nature produced by the meiotic division of microspore mother cells (located in the anther). The meiosis of these diploid (2n) microspore mother cells give rise to four haploid microspores. This process in plants is called microsporogenesis.
Each haploid microspore (n) develops into pollen grain called microgametophye (bearing male gamete) via mitotic division. During the pollen grain formation, a wall is formed around the microspores.