Pollen
/ˈpɑlən/
Definition
Pollen is a fine, powdery substance made in the anthers of seed plants. It consists of tiny grains that carry the male reproductive cells or the structures that produce them. During pollination, pollen moves to the stigma of a flower, or the female cone in gymnosperms, where it can enable fertilization. Its tough outer wall helps protect it during transfer by wind, water, or animals.
Role in Plant Biology
- Transfer to the stigma: In seed plants, pollen must reach a compatible stigma or ovule for fertilization to continue. This step links flower structure, pollinators, wind, and timing in plant reproduction.
- Species compatibility: Its outer wall carries traits used in recognition between plants of the same species. In many flowering plants, this helps reduce unsuccessful crosses and supports genetic stability.
- Clues for plant identification: Grain size, shape, and surface pattern can differ among plant groups. Botanists use these features in classification and in palynology, the study of microscopic grains and spores.
- Relevance in propagation: Gardeners and breeders may move it by hand to make controlled crosses or improve fruit set in plants that need cross-pollination. Success depends on viable grains, receptive flowers, and correct timing.
Related Terms
Pollination
Pollination is the transfer of pollen from the male part of a flower, the anther, to the female part, the stigma, of…
Stamen
Stamen refers to the male reproductive structure of a flower. It usually consists of a filament, the stalk, and an…
Theca
Theca refers to one of the two pollen sacs in a typical anther, the pollen-bearing part of a flower’s stamen. Each…
Microspore
Microspore refers to the small spore produced in the male sporangia of seed plants and many other land plants. It is…
Microsporangium
Microsporangium refers to the pollen-producing spore case in seed plants and other vascular plants. It is a plant…
Pin
Pin refers to a pollen grain that carries the genetic traits for the pin flower form in heterostylous plants, such as…