Pollination is the transfer of pollen from a flower's anther to a flower's stigma, stimulating germination as the pollen produces a tube which grows down the style to the egg in the ovule. While many flowers rely on bees, insects and wind for reproduction assistance, there are a few species that will self-pollinate, performing the act alone. This is possible if the flower has both female and male parts, and is not adapted to prevent self-pollination.
Both hermaphrodite and monoecious species have the potential for self-pollination leading to self-fertilization unless there is a mechanism to avoid it. Eighty percent of all flowering plants are hermaphrodite, meaning they contain both sexes, while 5 percent of plant species are monoecious, or unisexual.
Arum lilies, tridax (part of the daisy family) and some orchids are self-pollinating flowers. Dates, box-elder and buffalo berry are self-pollinating flowering trees. There are quite a few vegetables that self-pollinate, such as tomatoes, okra, peas, snap peas, soybeans and lima beans. In some cases, like the soybean, the flower will be open to cross-pollination during the day, but will self-pollinate if needed before closing.
There are several advantages for self-pollinating flowers. If a given genotype is well-suited for an environment, self-pollination helps to keep this trait stable in the species. Not being dependent on pollinating agents allows self-pollination to occur when bees and wind are nowhere to be found. Self-pollination can be an advantage when the number of flowers are small or widely spaced.
The disadvantages of self-pollination come from a lack of variation that allows no adaptation to the changing environment or potential pathogen attack. Self-pollination can lead to inbreeding depression, or the reduced health of the species, due to the breeding of related specimens. This is why many flowers that could potentially self-pollinate have a built-in mechanism to avoid it, or make it second choice at best.
Self-pollinators are more likely to be found in areas that lack pollinating agents or mates. It is likely then that geographic location has influenced the development of many self-pollinating species.
- Plant Biology; Lack, Andrew and Evans, David; 2005.
- Encyclopedia Britannica
- Photo Credit forteller: Flickr.com
A List of Self-Pollinating Vegetables
People new to gardening or those without the time or inclination to fuss with plants often choose self-pollinating vegetables due to their...
Why Do Most Flowering Plants Not Self-Pollinate?
Self-pollination produces clones of the parent plant, which reduces genetic variation within the plant population. The purpose of sexual reproduction is to...
Examples of Wind Pollinated Flowers
Every spring, evidence of wind-pollinated flowers can be seen in the feathered wisps of threadlike hairs with a small seed attached at...
List of Self-Pollinating Fruit Trees
Many small fruit bushes and vines, such as raspberries, blackberries and strawberries, are self-pollinating. Trees typically need another variety to cross-pollinate with....