Britannica Sources used in this answer

How does meiosis help complete the bryophyte life cycle?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

Thick green bryophyte moss covers the trunks of three oak trees in a forest, with fallen leaves on the ground. — bryophyte Bryophyte moss growing on oak trees.

In the life cycle of bryophytes, meiosis is the critical process that transitions the organism from the diploid sporophyte generation to the haploid gametophyte generation.1

This process occurs within the sporophyte's sporangium, where specialized cells known as sporocytes (or spore mother cells) undergo meiotic division. Each sporocyte divides to produce four haploid spores, which are released into the environment. These spores serve as the starting point for the gametophytic generation; upon germination, each spore develops into a multicellular, haploid gametophyte.21

By reducing the chromosome number by half, meiosis ensures that the life cycle can continue through the alternation of generations. Without this reduction, the subsequent fusion of gametes (syngamy) would lead to an unsustainable increase in chromosome numbers in each successive generation. Thus, meiosis and syngamy act as the two inseparable, alternating events that define the sexual life history of the plant.13