We explain what sporulation is, how this asexual reproduction mechanism works, examples and other forms of reproduction.
What is sporulation?
Sporulation is the mechanism of asexual reproduction through spores and endospores. This type of reproduction it is usual in mushrooms, plants and various genres of bacteria Y microorganisms. It can be part of their natural reproductive cycle, or an alternative to face adverse environmental situations, such as lack of nutrients or sunlight.
Although they are similar to animal gametes, the spores are characterized by being resistant structures: they consist of a single cell wrapped in a thick layer of organic material, which defends her from hostile environmental conditions, waiting for a more favorable situation to gestate a complete individual.
They are known to be tremendously resistant to radiation, desiccation, heat and even at the pace of weather. They are divided into:
- Endospores That are formed within the organism, generally unicellular.
- Exospores That are formed outside the body, through a process called gemmation.
Examples of sporulation
Ferns produce spores that adhere to their leaves.Next, we will see as an example sporulation in plants, fungi and bacteria:
- Bacterial sporulation. It consists of the replication of DNA bacterial, wrap it in a small portion of the cytoplasm, then coating it with peptidoglycan as the spore hardens and is finally released into the cellular environment. This procedure is commonly carried out by bacteria of the genera Bacillus, Clostridium and by some cyanobacteria.
- Sporulation in fungi. The procedure in fungi is similar to the bacterial one, insofar as genetic replication occurs through the mitosis, except that in the case of multicellular fungi this process is carried out in specialized structures known as asci, basidia, conidiophores or sporangia, depending on the type and species of fungus. These are then released at environment, generally by air, and transported by the wind to new destinations. The spore-producing fungi belong to the ascomycetes, basidiomycetes, conidiophores (imperfect fungi), zygomycetes, glomeromycetes or chytrids.
- Sporulation in plants. Many plant species have a reproductive mechanism that alternates from generation to generation, between spore production and gamete production. Many of these spores are differentiated into female and male, just like animal gametes, since they are formed by meiosis (and not by mitosis). These spores are classified into microspores (which give rise to pollen) and macrospores (which give rise to ovules within the flower). Both angiosperms and gymnosperms are known to use this reproductive method, as well as green algae, rhophytic algae, and other known types.
Other forms of asexual reproduction
In addition to sporulation, there are other non-sexual reproduction mechanisms (that is, they involve a single individual and have little or no genetic variation), such as:
- Binary fission. Typical of single-celled organisms, consists of the replication of DNA and cellular content, until a double individual is formed that will later separate, through the narrowing of the plasma membrane, in two new genetically identical individuals.
- Gemmation. It consists of the formation of extensions or prominences of the body of the progenitor, which then can separate from him and have a life of their own, or stay together and start a colony. It can also occur at the cellular level, as an asymmetric mitosis process.
- Parthenogenesis. Typical of certain animals (flatworms, rotifers, tardigrades, insects, amphibians, fish and crustaceans, but also some reptiles), consists of the development of a new individual, although genetically equal to the parent, through the development of unfertilized female sex cells.