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Pollination is the first reproductive step for plants to reproduce. Two plants are normally required for this to occur, but there is a mechanism in which one plant can pollinate itself. This process is known as self-pollination and, in this Green Ecologist article, we are going to explain what is self-pollination, how it differs from cross pollination and if this strategy has more benefits than disadvantages.
What is self-pollination and other types of pollination
Plants need pollination so that pollen from male floral anthers reaches the stigma, located on the pistil, and thus can germinate. From this, the pollen tube develops that joins the male and female gamete so that they are fertilized and the diploid zygote is created.
To achieve self-pollination, the pistil is sticky so that pollen can be easily trapped when it gets close to the stamens. This usually occurs during a process called cleistogamy, where pollination occurs before the flower opens, taking advantage of the closeness between the pistils and stamens. Self-pollination can happen too when the flower is open, where any small movement makes the pollen grains reach the female stigma. In extreme cases, some plants can wait to be pollinated and, if not, they can shut down and self-pollinate. This case is visible in soybeans.
There are several ways for pollination to occur, but the most peculiar is the direct pollination, which occurs when there is self-pollination. In this case, the plants have the ability for the stamens to pollinate the stigma of the same flower, without an external pollinator. These species are self-pollinated, that is, the female and male gametes of the same plant come together. All plants that can self-pollinate should be hermaphrodite, since they need both plant reproductive systems.
In these other articles you can find more information about Hermaphrodite plants: what they are, characteristics and examples or Parts of a plant and their functions.
Pollination types
Other types of pollination can be classified as natural or artificial. Next, we are going to see them in more detail:
- Natural pollination: they can be entomogamous pollinations (when insects such as bees intervene) or zoophilic (when pollen adheres to feathers or animal fur). It can also be dispersed by abiotic means, being anemophilic, when the wind helps to pollinate or hydrophilic by water transport.
- Artificial pollination: it is carried out by man, who intervenes in the fertilization process. This method is used when you want to have greater control of progeny, so that they have particular characteristics or if there is a shortage of pollinators by isolation, especially for pollination of crops. It can be carried out with a toothpick or brush to transfer pollen.
Here you can read more about what pollen is and what it is for.
Difference between self pollination and cross pollination
Self-pollination and cross-pollination are two different strategies. Therefore, below we are going to specify the differences between self-pollination and cross-pollination.
- Self pollination: it does not need external elements to pollinate it, nor does it need pollen from other plants of the same species. The flowers of autogamous plants can be of small sizes and not so bright colors, since evolutionarily they have not had the need to develop these strategies. Self-pollinating plants are the less frequent. Some examples of self-pollinating plants are peas, the Santa Rosa plum (Prunus domestica), tomatoes, soybeans or some orchids like Ophrys apifera.
- Cross pollination: it does need pollen from other plants. In this cross-pollination, natural means of transport such as wind, water or insects are necessary and, to attract the latter, the flowers have bright colors to which arthropod vision responds. Cross-pollinating plants are the more frequent.
In this Green Ecologist article we give you more information about the Importance of pollination so that you can learn more about it.
Advantages and disadvantages of self-pollination
The self-pollination process is a very peculiar reproductive strategy, so it triggers different advantages and disadvantages.
Advantages of self-pollination
Some of the advantages of the entire self-pollination process are:
- They do not require external causes to complete its reproduction: this also means that it does not depend on other plants of its species to pollinate itself, thriving wherever it is inserted and many times becoming invasive plants, pests or weeds.
- Zero pollen waste: pollen is not lost in the wind, water or animals, making the production of these reproductive cells more efficient. This advantage of autogamy is special for small flowers, which cannot produce large amounts of pollen and need to use as much pollen as possible.
- Generation of descendants: with purer lineages and more uniform genetics.
- Adaptation to particular ecosystems: In each new generation plants equally well adapted to the particular environment they already inhabit are reproduced.
Disadvantages of self-pollination
Some of the disadvantages that the self-pollination process can present are the following:
- Genetic impairment due to lack of recombination: the purpose of self-fertilization is to increase the number of homozygotes so that recessive genes are expressed, but since it is a type of endogamous reproduction, a deterioration of genetic recombination is generated that results in the accumulation of harmful recessive genes.
- Adaptive plasticity reduction: the lack of genetic exchange also exposes them to pests, diseases or changes in the environment, before which they have not developed adaptation strategies.
- Affected fertility: it is very common in all those organisms that reproduce endogamically.
On the other hand, in plants it is common for homozygosity to result in excellent adaptations to particular ecosystems, reproducing equally well-adapted plants in each new generation.
If you want to read more articles similar to What is self-pollination, we recommend that you enter our Biology category.
Bibliography- Medawar, P., & Medawar, J.S. (nineteen ninety six). From Aristotle to Zoos, Philosophical Dictionary of Biology. Mexico City: Economic Culture Fund.
- Hernández, H., García, A., Álvarez, F., & Ulloa, M. (2001). Contemporary approaches to the study of biodiversity. Mexico City: Institute of Biology of the Autonomous University of Mexico.
