The gemmation Is a type of asexual reproduction that is present in both unicellular and multicellular beings. It is the formation of a new individual, either animal or vegetable, by a process of sprouting by cell division.
The new organism remains united as it grows, separating from the parent organism only when it is mature, leaving scar tissue behind.
Organisms such as hydra use regenerative cells to reproduce in the budding process. In hydra, an outbreak develops due to repeated cell division at a specific site. These outbreaks become tiny individuals and, when fully mature, separate from the parental body, becoming independent individuals.
Some cells divide asymmetrically by sprouting, for example Saccharomyces cerevisiae, yeast species used in cooking and brewing. This process results in a 'mother' cell and a smaller 'daughter' cell.
In some multicellular animals (metazoans), the offspring can be developed from the budding of the mother. Animals that reproduce by budding include corals, some sponges, flatworms (eg Convolutriloba) and echinoderm larvae.
It is more common in certain types of bacteria, although there are animal species that reproduce also thanks to the budding. Through this process, a new organism emerges that is genetically identical to its parent, which makes it what we can call replica.
This is because during the budding process, the parent and the new organism share the same genetic code (DNA) and is transmitted completely.
The budding occurs when a yolk emerges, which in some species may appear from any part of the body of the parent. However, in many other cases, the bud is only produced in specialized areas for this work.
After the budding process, the new individual can completely separate from his parent and become an independent organism, or, on the contrary, stay united and be part of what is known as a colony.
A representative case of this type of budding, in which the individual does not become an autonomous organism, is the coral.
On the other hand, in multicellular beings, the budding process is more frequent in aquatic organisms, such as poríferas. And among which is the sea sponge; Bryozoans, moss animals and cnidarians such as corals or anemones.
In unicellular beings, budding occurs through a process of asymmetric mitosis. Generally, during the budding process, in some species, a bulge called bud is formed in the plasma membrane or cell membrane.
Geology in botany and agriculture
The budding process takes place in different plant species. Thanks to this, farmers use this method to achieve a controlled reproduction of the specimens they want.
This method is used to convert a plant (the rootstock) into another type of plant with the desired characteristics. It should be noted that the plants obtained through the budding method have, frequently, shortened stature and maturity compared to the plants propagated from the seeds.
This method of reproduction has the advantage of producing numerous clones from a single stem, node or branch. It is especially used when there is a limited number of stems for the graft. One of the advantages of reproduction by budding in agriculture is the elimination of the need to transport voluminous stems.
In agriculture, the budding process has about six stages. Various techniques are used, especially applicable in growing young plants, which have stems in which the bark is more easily separated from the wood. Among the stages in the budding process are:
- Preparation of rootstock
- Preparation of the outbreak
- Insertion of the prepared bud
- Tie the wrap
- Cutting the back of the rootstock
- Care of the resulting shoots and clones.
Reproduction by budding in the animal kingdom
Although asexual reproduction by budding is commonly associated with bacteria and yeasts, there are some animal species that also reproduce through this method.
Animals that reproduce by budding are generally basic organisms, almost always without reproductive organs or with both organs, both female and male, located internally.
Some examples of animal organisms reproduced by budding are the following:
Flatworms
Although not all flatworms reproduce asexually, a large number of species do.
Most use fragmentation and budding as a mode of reproduction. These species generate self-fertilized eggs that will later be released.
From these eggs, which will be divided up, new complete organisms will be born.
Among flat worms is the parasite known as tapeworm, which, like all parasites, uses reproduction by budding as this method ensures that the offspring will be born in the appropriate habitat, ie the host organism.
Jellyfish
Although all species of jellyfish are not reproduced exclusively by budding, it is one of the most common reproduction processes in this animal organism.
During this method, the specimen releases sperm and an egg into the water. Once fertilized, the sperm and egg grow in an organism called polyp.
This polyp grows, attached to the base of a rock, until it releases a bud or genetic button identical to itself. That yolk will grow into an adult jellyfish specimen.
Corals
As mentioned above, during the budding process, the bud or yolk can be separated from its parent or, on the contrary, hold together and create what we know as a colony.
Corals use the budding as a form of asexual reproduction and remain attached to their parents after development.
This results in accelerated and mass growth and ends up becoming coral reefs: gigantic colonies of thousands or millions of joined corals after breeding by budding. This union of organisms shares almost all of the genetic material despite being composed of so many individuals.
Hydra
Hydra is a hydrozoan (cnidarian) that measures about a centimeter, its body is composed of a tubular segment, with head, distal end and a sort of standing at the end.
This organism has the capacity to reproduce both sexually and asexually. The hydra lives in fresh water and is hermaphrodite. Its mode of reproduction depends, to a large extent, on the characteristics of its surroundings.
When the conditions are favorable and the food is abundant, the hydra is reproduced by budding.
During this process, buds appear on the body wall of the hydra that will then simply separate from their parent and give life to a new organism. This occurs by cellular mitosis. However, when food is scarce or conditions are adverse, hydra can reproduce sexually.
Other characteristics of cells
Cell membrane of cells
This membrane, also called cytoplasmic membrane or plasmalema, is composed of a lipid bilayer that surrounds the whole cell. Thanks to this membrane, the balance between the exterior (extracellular medium) and the interior (intracellular medium) of the cell is maintained.
This is so because this regulates properly the molecules that enter or leave the cell or its components, such as the cytoplasm. It is in this part of the organism that we develop what we call yolk.
The main feature of the cell membrane is its selective permeability. This feature allows the selection and filtration of substances that enter or leave the cell.
Thanks to this selective permeability, the intracellular medium is kept stable. That is, the cell membrane serves as the regulator and stabilizer of the cell, protecting it from external agents and helping it in its internal processes.
Other functions characteristic of the cell membrane are the delimitation and protection of the cell, the ability to receive signals and respond appropriately in cases such as cell division and the elaboration of compounds necessary for the cell, among others.
Thus, you can imagine the cell membrane as a large plastic bag with some tiny holes. This coating allows all previously mentioned processes and characteristics to be carried out, at the same time that it gives way to the substances required for the correct development and stability of the cell.
In this sense, it is important to note that the cell membrane is not a solid structure since it is composed of millions of flexible molecules that make up a porous container, in which proteins and phospholipids, among others, are found.
Asexual reproduction in cells
Mitosis is the main basis of asexual reproduction. It's about a Asexual reproduction type In which descendants are produced that are genetically identical to their progenitors.
This type of reproduction differs from sexual reproduction since it takes only one individual to perform, while in the sexual it is necessary for both parents to participate in the reproductive act.
Because it is a single individual, there is no fusion of gametes and there is no mixing of the genetic material. Perhaps in this link you are interested in knowing what the Types of sexual reproduction .
Asexual reproduction occurs in microorganisms such as bacteria, and in multicellular organisms such as some types of animals and plants.
In the animal kingdom there are different types of asexual reproduction between which is the bud. In addition to this type of reproduction, we can also find:
Fragmentation
Fragmentation consists of the partition or, as its name implies, fragmentation of the individual into at least two parts. If any of these parts (or all of them completely) is of sufficient size, an extra individual will grow.
The starfish is an example of the process of reproduction by fragmentation. If one of your arms is cut, and has enough genetic material, a new star will grow from the fragment.
Unlike fission reproduction (which we will see below), in the fragmentation the resulting individuals may have different sizes.
Fission
This type of asexual reproduction, also called binary fission, occurs in prokaryotic microorganisms and in some multicellular invertebrates.
Fission occurs after the individual goes through a certain period of growth. This organism will later be divided into two new organisms, almost always of the same size. The sea anemone is an example of reproduction by fission or binary fission.
Parthenogenesis
Parthenogenesis is a form of asexual reproduction in which an unfertilized egg becomes a complete individual. The offspring resulting from this breeding process may be haploid or diploid.
This means that individuals can be produced in which the cells possess two sets of chromosomes (diploid) or a single series (haploid). This type of asexual reproduction occurs in animals such as aquatic fleas, stick insects, and in some types of bees, ants, among others.
Diploid cells and haploid cells
- Diploid cell: Diploid cells are those that have the number and composition of chromosomes normal. This means that, in other words, they have a double number of chromosomes (two sets of chromosomes). The diploid number or character is represented by the digit 2n.
- Haploid cell: Haploid cells are those that possess only half the normal number of chromosomes. In humans they are found in gametes (spermatozoa in man and ova in woman). The rest of the cells of a higher organism are, in a normal way, diploid cells. The haploid number is represented by n.
References
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- Encyclopedia Britannica. The Editors of Encyclopædia Britannica. Reproduction. (September 4, 2015) Obtained from global.britannica.com.
- Andrew Rader. Biology4kids. "Cell structure"Cell membranes. (February 27, 2017) obtained from biology4kids.com.
- Co.uk. Science. Reproduction and cloning. (2014) Retrieved from http://www.bbc.co.uk.
- Budding. (July 8, 2016). Obtained from byjus.com.
- Ben G. Bareja. Cropsreview.com. "Budding"(November 2011) obtained from cropsreview.com.
- "A list of animals that reproduce using budding". (February 2017) Retrieved from animals.mom.me.