What is self pollination

Pollination is the first reproductive step in plants for them to reproduce. Two plants are normally required for this to occur, but there is a mechanism where a plant can pollinate itself. This process is known as self-pollination.

What is self-pollination and other types of pollination

Plants need pollination so that the pollen from the male floral anthers reaches the stigma, located in the pistil, and thus can germinate. From this, the pollen tube develops that joins the male gamete with the female 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 caught as it approaches the stamens. This usually occurs during a process called cleistogamy, where pollination occurs before the flower opens, taking advantage of the proximity between the pistils and stamens. Self-pollination can also happen when the flower is open , where any small movement causes the pollen grains to reach the female stigma. In extreme cases, some plants may wait to be pollinated, and if not, they may close down and self-pollinate. This case is visible in soybeans.

There are several ways for pollination to occur, but the most peculiar is 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 autogamous, that is, the male and female gametes of the same plant unite. All plants that can self-pollinate must be hermaphrodites , since they need both plant reproductive systems.

types of pollination

Other types of pollination can be classified as natural or artificial. Next, we will see them in more detail:

  • Natural pollination : they can be entomogamous pollinations (when insects such as bees are involved) or zoophilic (when the pollen adheres to feathers or animal fur). It can also be dispersed by abiotic means, being anemophilous, 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 the progeny , so that they have particular characteristics or if there are few isolated pollinators, especially for crop pollination. It can be carried out with a toothpick or brush to transfer the pollen.

Difference Between Self Pollination and Cross Pollination

Self-pollination and cross-pollination are two different strategies . Therefore, below we are going to specify what the differences are 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 vivid colors, since evolutionarily they have not had the need to develop these strategies. Self-pollinating plants are the least frequent . Some examples of self-pollinating plants are peas, the Santa Rosa plum ( Prunus domestica) , tomatoes, soybeans, or some orchids such as Ophrys apifera .
  • Cross-pollination : you do 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-pollinated plants are the most frequent .

Advantages and disadvantages of self-pollination

The self-pollination process is a very peculiar reproductive strategy, which is why it triggers different advantages and disadvantages.

Advantages of self-pollination

Some of the advantages that the whole process of self-pollination entails are:

  • They do not require external causes to complete their reproduction: this also means that they do not depend on other plants of their species to pollinate themselves, thriving wherever they are inserted and often becoming invasive plants, pests or weeds.
  • Zero pollen waste : Pollen is not lost to 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 take advantage of as much as possible.
  • Generation of descendants : with purer lineages and more uniform genetics.
  • Adaptation to particular ecosystems : Plants equally well adapted to the particular environment they already inhabit are reproduced in each new generation.

Disadvantages of self-pollination

Some of the disadvantages that the self-pollination process can present are the following:

  • Genetic deterioration due to lack of recombination : the purpose of self-fertilization is the increase of homozygotes so that the recessive genes are expressed, but since it is a type of inbreeding, a deterioration of genetic recombination is generated that results in the accumulation of recessive genes harmful.
  • Reduction of adaptive plasticity : the lack of genetic exchange also exposes them to pests, diseases or changes in the environment, to which they have not developed adaptation strategies.
  • Affected fertility : it is very common in all those organisms that reproduce inbreeding.

On the other hand, in plants it is common for homozygosity to result in excellent adaptations to particular ecosystems, reproducing in each new generation equally well-adapted plants.

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