noun, plural: microspores
(botany) A developing pollen grain at the uninucleate stage in seed plants
In botany, a microspore refers to the spore produced by sporophytes. It is haploid and gives rise to a male gametophyte. Metagenesis or the alternation of generations involves the alternation of life phases in the life cycle of plants. The sporophyte, in particular, produces spores (thus the name) to give rise to the next phase, which is the gametophyte. Gametophytes, on the other hand, produce gametes that give rise to sporophytes. A mature sporophyte produces spores by means of meiosis. The diploid sporophyte thus bears spores that are haploid, i.e. the number of chromosomes is half of the number of those of a sporophyte. The spore produced by sporophytes may be a microspore or a megaspore. The microspore is generally smaller in size compared with the megaspore. And the microspore develops particularly into a haploid male gametophyte. The megaspore, in comparison, develops into a haploid female gametophyte.