gametophytte

Gametophyte is a term used in botany to describe the haploid stage in the life cycle of plants and algae that alternates with a diploid stage called the sporophyte. The gametophyte generation produces gametes, which are sex cells, through mitosis. These gametes, typically sperm and egg, then fuse during fertilization to form a diploid zygote. This zygote then develops into the sporophyte.

In bryophytes, such as mosses, liverworts, and hornworts, the gametophyte is the dominant and more visible phase of the life cycle. It is typically a small, green, leafy or thalloid structure that carries out photosynthesis. The sporophyte in bryophytes is usually dependent on the gametophyte for nutrition and is a stalk-like structure that bears spores.

In ferns and other vascular plants, the sporophyte generation is dominant and easily recognizable as the familiar plant body. The gametophyte, also known as a prothallus in ferns, is usually small, inconspicuous, and short-lived. It may be free-living or partially dependent on the sporophyte. In seed plants, the gametophyte is highly reduced. The female gametophyte is retained within the ovule and develops into the embryo sac, while the male gametophyte develops into pollen grains. The fusion of gametes within these structures leads to the formation of a new sporophyte generation. The alternation of generations between gametophyte and sporophyte is a fundamental characteristic of the plant life cycle.