microgametofyt

Microgametophyte is the male gametophyte in the life cycle of seed plants, representing the haploid generation formed from a microspore by meiosis. In gymnosperms and angiosperms, microsporogenesis occurs in microsporangia of the male sporophyte (anthers in flowering plants, male cones in gymnosperms), producing microspores that develop into pollen grains. The pollen grain is typically covered by a robust outer wall (exine) and an inner wall (intine).

In angiosperms, the mature pollen grain usually contains two cells: a tube cell and a generative cell. The generative cell eventually divides to form two sperm cells. The tube cell guides pollen germination and pollen tube growth, enabling the sperm to reach the ovule interior. The microgametophyte is therefore a short-lived, largely non-photosynthetic structure that functions primarily to deliver sperm to the female gametophyte.

In gymnosperms, the male gametophyte is carried by the pollen grain to the ovule where the pollen tube grows toward the female tissues to deliver sperm for fertilization. Fertilization results in the formation of a zygote, which develops into the sporophyte embryo. Throughout this process, the microgametophyte is transient and dependent on sporophytic tissues for resources.

Terminology and relation to megagametophyte: microgametophyte is the male counterpart to the megagametophyte, the latter being the haploid female gametophyte that develops within the ovule. The microgametophyte’s primary role is to achieve fertilization, after which it typically ceases to persist.