pollination
-
What is pollination?
Pollination is the process of transferring pollen grains from a flower's stamen to its ovules, facilitating fertilization and seed production. This is essential for the reproduction of most wild plants and the production of many fruits and seed crops.
Flowering plants rely on external agents for pollen transport, including insects, wind, birds, mammals, and water. Animal pollinators, especially insects and bees, play a crucial role in ecosystems and agriculture by pollinating various fruit and vegetable crops. Declines in pollinator populations, such as bees, can have significant ecological and economic consequences.
5 Britannica SourcesCreated from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles. -
Why is pollination important for plants?
Pollination is vital for the continuation of both wild plants and the majority of fruit and seed crops, ensuring the stability of terrestrial ecosystems and global food production.
Effective pollination involves the transfer of pollen grains to a stigma of the same species, leading to fertilization and seed development. This process is often facilitated by external agents like insects, wind, birds, mammals, and water. Among these, bees stand out as crucial pollinators, responsible for the reproduction of numerous plant species and the formation of fruits and seeds.
A decline in bee populations could trigger a significant reduction in plant biodiversity, affecting entire ecosystems and human agriculture.
5 Britannica SourcesCreated from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles. -
Which animals or insects help with pollination?
Pollination relies on various animals and insects to transfer pollen between plants, ensuring the continuation of ecosystems and the production of many crops.
Bees are among the most important insect pollinators, with over 20,000 species that feed on nectar and pollen. They have physical and behavioral adaptations such as hairy bodies and long tongues to aid in pollination. Other insect pollinators include beetles and flies. Some flowers attract carrion beetles and flesh flies with a smell of rotting flesh.
4 Britannica SourcesCreated from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles. -
How do plants attract pollinators?
Plants attract pollinators through a variety of adaptations, including advertising and sexual deception.
- Coloration The coloration and patterns of flowers attract pollinators and signal plant species. Flowers pollinated by insects often display yellow, blue, and ultraviolet patterns, which elicit a strong response in the insect eye. Nectar guides, which are darkly colored patterns near the flower's center, orient the insect toward the proper pollinating location.
- Scent Many flowers produce odors from volatile secondary compounds, including aromatic phenolic compounds, that attract pollinators. Some plants, like bee orchids, mimic the scent, appearance, and texture of a female bee to lure male bees into "pseudocopulation." During this process, the flower releases pollen on the bee, which then pollinates the next flower the bee visits.
- Nectar Nectar in flowers attracts pollinators such as insects, birds, and bats. Nectaries are located at the base of the flower stamens, which brings animal visitors into contact with the pollen to be transferred.
5 Britannica SourcesCreated from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles. -
What happens if plants do not get pollinated?
If plants do not get pollinated, they cannot produce seeds, which are essential for creating new plants. Pollination is vital for the continuation of most wild plants and the production of many fruits and seed crops.
Bees are among the most important pollinators, and the decline of bee populations can have ripple effects throughout entire ecosystems. Some plants are pollinated exclusively by specific bees and would die off without them, which would alter habitats and food webs. While the majority of human calories come from cereal grains, which are wind-pollinated, the diversity and availability of fresh produce would decline substantially without animal pollination.
6 Britannica SourcesCreated from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles. -
How does pollination affect the ecosystem and food supply?
Pollination is vital for the majority of the world’s wild plants and terrestrial ecosystems, as well as for producing most of the fruit and seed crops that feed humanity. Bees are the most important insect pollinators, playing a crucial role in the reproduction of flowering plants and the creation of fruits and seeds.
Without pollinators, many plants would struggle to reproduce, causing a decline in plant biodiversity that would affect entire ecosystems and human agriculture. The plants that bees help to sustain serve as food and shelter for wildlife. Additionally, bees are food for other organisms in the food web.
In agriculture, bees pollinate numerous fruit and vegetable crops. Without bees, the scale and cost of growing many fruits and vegetables would be drastically affected, leading to higher prices and reduced availability of these foods.
5 Britannica SourcesCreated from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.
News •
pollination, transfer of pollen grains from the stamens (the flower parts that produce them) to the ovule-bearing organs or to the ovules (seed precursors) themselves. In gymnosperm plants such as conifers and cycads, in which the ovules are exposed, the pollen is simply caught in a drop of fluid secreted by the ovule. In flowering plants, however, the ovules are contained within a hollow organ called the pistil, and the pollen is deposited on the pistil’s receptive surface, the stigma. There the pollen germinates and gives rise to a pollen tube, which grows down through the pistil toward one of the ovules in its base. In an act of double fertilization, one of the two sperm cells within the pollen tube fuses with the egg cell of the ovule, making possible the development of an embryo, and the other cell combines with the two subsidiary sexual nuclei of the ovule, which initiates formation of a reserve food tissue, the endosperm. The growing ovule then transforms itself into a seed.
As a prerequisite for fertilization, pollination is essential to the perpetuation of the vast majority of the world’s wild plants as well as to the production of most fruit and seed crops. It also plays an important part in programs designed to improve plants by breeding. Furthermore, studies of pollination are invaluable for understanding the evolution of flowering plants and their distribution in the world today. As sedentary organisms, plants usually must enlist the services of external agents for pollen transport. In flowering plants, these are (roughly in order of diminishing importance) insects, wind, birds, mammals, and water. See also major types of pollinators.
Types: self-pollination and cross-pollination
An egg cell in an ovule of a flower may be fertilized by a sperm cell derived from a pollen grain produced by that same flower or by another flower on the same plant, in either of which two cases fertilization is said to be due to self-pollination (autogamy); or, the sperm may be derived from pollen originating on a different plant individual, in which case the process is called cross-pollination (heterogamy). Both processes are common, but cross-pollination clearly has certain evolutionary advantages for the species: the seeds formed may combine the hereditary traits of both parents, and the resulting offspring generally are more varied than would be the case after self-pollination. In a changing environment, some of the individuals resulting from cross-pollination still may be found capable of coping with their new situation, ensuring survival of the species, whereas the individuals resulting from self-pollination might all be unable to adjust. Self-pollination, or selfing, although foolproof in a stable environment, thus is an evolutionary cul-de-sac. There also is a more direct, visible difference between selfing and outbreeding (cross-pollination): in those species where both methods work, cross-pollination usually produces more, and better quality, seeds. A dramatic demonstration of this effect is found with hybrid corn (maize), a superior product that results from cross-breeding of several especially bred lines.
" height="20" alt="HEW Logo">