Sporofüüd

Sporofüüd is a term used in botany to describe the multicellular diploid stage in the life cycle of organisms belonging to the kingdom Plantae, as well as to some algae. It is the stage that follows fertilization, where the zygote develops into an embryo and then into a mature sporophyte. This mature sporophyte is characterized by its diploid nature, meaning its cells contain two sets of chromosomes, one inherited from each parent.

The sporophyte generation is responsible for producing spores through meiosis. These spores are haploid, containing only one set of chromosomes. When conditions are favorable, these haploid spores germinate and develop into the gametophyte generation, which is the multicellular haploid stage. The gametophyte, in turn, produces gametes (sperm and egg cells) through mitosis. Fertilization occurs when a sperm and an egg fuse, forming a diploid zygote, thus completing the life cycle and initiating the next sporophyte generation.

In most land plants, the sporophyte generation is dominant and conspicuous, while the gametophyte is reduced or inconspicuous. For example, in ferns, the large, leafy plant is the sporophyte, and the small, heart-shaped gametophyte is often overlooked. In flowering plants, the sporophyte is the familiar plant we see, while the gametophytes are very small, residing within the reproductive structures like pollen grains and ovules. The alternation of generations between the sporophyte and gametophyte is a fundamental characteristic of plant life cycles.