gametofüütide

Gametophytes are the haploid multicellular stage in the life cycle of plants and algae that alternates with the diploid sporophyte generation. This alternating generation is known as alternation of generations. The gametophyte produces gametes, which are sex cells, through mitosis. These gametes, upon fusion during fertilization, form a diploid zygote, which then develops into the sporophyte.

In lower plants like mosses and liverworts (bryophytes), the gametophyte is the dominant, free-living generation, often appearing as the green, leafy part of the plant. The sporophyte in these groups is typically smaller, dependent on the gametophyte for nourishment, and often appears as a stalk with a capsule.

In ferns and their allies (pteridophytes), the sporophyte is the dominant generation, forming the familiar fronds and roots. The gametophyte, called a prothallus, is small, heart-shaped, and typically lives independently but briefly underground or on the soil surface, bearing the reproductive organs.

In seed plants (gymnosperms and angiosperms), the gametophyte generation is greatly reduced and dependent on the sporophyte. The female gametophyte is the ovule, which develops into the embryo sac within the ovary of flowering plants. The male gametophyte is the pollen grain, which contains the sperm cells. These reduced gametophytes are not free-living and are entirely nourished by the sporophyte. The structure and dominance of the gametophyte generation vary significantly across different plant groups.