Pollinatsiooni

Pollinatsiooni, or pollination, is the transfer of pollen from the male anther of a flower to the female stigma, enabling fertilization and seed production. Pollination can occur within a single flower, between flowers on the same plant, or between plants of different individuals. It happens through biotic agents, such as pollinators, or abiotic agents, such as wind or water.

Biotic pollination is carried out mainly by animals, including insects (bees, butterflies, moths, beetles), and, in some ecosystems, birds and bats. Wind pollination is common in grasses, many trees, and some shrubs and crops, producing large quantities of light pollen that travels through the air. Pollination efficiency depends on compatibility between pollen and stigma, pollen viability, and the timing of flower receptivity.

In plants, pollen grains landing on a compatible stigma germinate, forming a pollen tube that grows through the style to reach the ovule. Sperm cells travel within the tube to fertilize the egg, resulting in a zygote that develops into a seed, while the ovary often matures into fruit.

There are two main natural strategies for fertilization: self-pollination, where pollen fertilizes ovules on the same plant, and cross-pollination, where pollen moves between different individuals. Cross-pollination generally increases genetic diversity and can improve offspring fitness.

Pollination is essential for many crops and for the reproduction of a wide range of wild plants. Animal pollination supports biodiversity and agricultural yields; estimates commonly indicate that about one-third of global crop production depends on animal pollinators to some extent. Threats to pollinators, such as habitat loss, pesticide exposure, diseases, and climate change, can reduce pollination success and crop yields. Conservation efforts include maintaining diverse foraging habitats, creating flowering margins, reducing harmful pesticide use, and supporting healthy pollinator populations.