You have studied reproduction in lower level classes. It is the process by which an organism is able to produce its young ones. Now tell me how we came to this world? Yes, we came to this world through our parents by sexual reproductive method. But can you imagine a situation where a child is born from the finger of his or her mother through the asexual reproductive method !! Seems impossible?
Yes, but it happens in certain living organisms. In organisms like yeasts, a daughter cell arises from the parent body without undergoing fertilisation. This is an asexual mode of reproduction in which an outgrowth arise from the parent body. This outgrowth is known as bud. It collects nutrients from the surroundings and grows. After some time, it detaches from the parent body and develops into a new independent organism.
Fig: Budding in yeast
This mode of reproduction is known as budding and it usually occurs in unicellular and simple organisms mainly. It is not possible in humans or any higher level multicellular organisms. Let’s take a deep dive into the details of budding in depth in this article.
Table of contents
The production of offsprings by a single parent without the formation and fusion of gamete is called asexual reproduction. It is uniparental. Budding is one of the types of asexual reproduction. Formation of an individual daughter from a small bud arising on the parent body is called budding.
The offspring produced through this method are genetically and morphologically identical to the parent organism. This is because only one parent is involved in this process and there is no meiosis or fusion of gametes which can lead to genetic variations or recombinations.
In budding, a cytoplasmic perturbation occurs in the basal region of the parent body and forms a bud. The bud grows and develops by getting nutrition from the parent body. After some growth, the bud detaches from the parent body and develops into a new organism. This type of asexual reproduction can be found in some organisms, such as bacteria, yeast, protozoans and cnidarians.
The budding is categorised into types based on the location of bud formation as follows:
The endogenous budding is a method of asexual reproduction in which the bud formation takes place inside the parent body. This type of budding is commonly seen in freshwater and marine sponges which are the members of the phylum Porifera. Examples include Spongilla. During this type of asexual reproduction, several buds called gemmules are formed and mature inside the parent body.
Each gemmule is formed of a mass of undifferentiated archaeocytes surrounded by a protective coat of spicules. When the sponge body degenerates during unfavourable conditions, gemmules are released into the water. During favourable conditions archaeocytes come out through the micropyle and develop into individual organisms.
Fig: Endogenous budding in Spongilla
Exogenous budding is a type of asexual reproduction that takes place in certain living organisms. During this process, an outgrowth or bud forms on the outer surface of the parent body. It develops externally by obtaining nutrition from the surrounding environment. It matures and detaches from the parent organism and develops into an individual organism.This is commonly seen in Hydra and yeast.
Fig: Budding in Hydra
Budding normally occurs in yeasts and in some filamentous fungi. During this process a bud develops on the surface of the yeast cell or the fungal hyphae. Here the cytoplasm of the bud is seen as continuous with that of the parent cell or fungal hyphae .
Budding in yeast
Yeast is described as a unicellular and achlorophyllous microorganism that belongs to the kingdom Fungi. An example is Saccharomyces cerevisiae, which is also known as brewing or baking yeast. It reproduces by developing small outgrowths, known as buds, from their vegetative bodies. The nucleus of the parent organism divides and produces one daughter nucleus. This daughter nucleus is received by the bud and as a result, a small daughter cell and a large mother cell are formed. Sometimes the newly formed buds remain attached to the parent cell for a long time and this forms a chain of buds called pseudomycelium. The buds detach eventually from the parent cell and develop into new organisms.
Fig: Budding in yeast
In yeast, a parent cell with buds bearing its own buds resembles the fungal genus Torula in appearance. Hence the budding in yeast is also called torulation.
Coelenterates are mostly marine, sessile, free-swimming organisms. They show budding. Examples include Hydra, Obelia, sea anemone and jellyfish.
Budding in Hydra
Hydra reproduces through budding when it is healthy and the food resources are high during the summer months. The repeated multiplication occurs in the interstitial epidermal cells due to which a bulge appears near the middle or basal part of the parent body in Hydra. This bulge develops into a bud later. The wall of the bud contains the epidermis and gastrodermis. The internal lumen of the bud develops along with the gastrovascular cavity of the parent Hydra. The bud develops a mouth when it grows bigger. At the free end of the bud, tentacles also develop. The bud starts constricting at the base and detaches from the parent body when it is fully grown. Then it receives nutrients from the surroundings and grows and matures into an adult Hydra.
Fig: Budding in Hydra
Sometimes, several buds develop simultaneously on a single parent organism in certain coelenterates like Obelia during the process of budding. Later these buds may develop secondary buds too. All these buds together form a group known as a colonial hydroid.
Budding in sea anemones and jellyfishes
In specific phases or stages of their life cycles, sea anemones (Adamsia) and jellyfishes also adopt the budding process. In jellyfish, the polyp form reproduces by budding. On the other hand, medusa has gonads that contain gametes.
Fig: Budding in Jellyfish
In poriferans or sponges, reproduction takes place through the process of budding. At the base of the sponge, an outgrowth arises that forms a bud. At the free end of the newly formed organism an osculum is also formed. The fully grown bud either remains attached to the parent sponge or detached from the parent sponge to form a new sponge. When a bud affixes to a fresh substrate and grows, then a fresh sponge colony can develop there. Therefore, a number of sponges are formed in a colony by this type of reproductive method. In Sycon, the buds are normally seen attached to the parent sponge and become a more or less independent member of the colony.
Fig: Budding in sponges
Protozoans like Toxoplasma gondii favour endodyogeny. It is an unusual method of asexual reproduction adopted by parasites. In this method, two daughter cells are produced inside a mother cell without nuclear conjugation. The mother cell is then consumed by the offspring prior to their splitting.
Some flatworms or Platyhelminthes can also reproduce through budding. This ensures their survival even in challenging circumstances. All types of parasitic flatworms normally use budding. Examples include tapeworms. During the budding process the flatworm grows an extension from its body. This extension, or bud, later becomes a new worm and gets separated from the parent flatworm.
Plants also can reproduce through budding. It is coming under vegetative propagation in plants. Vegetative propagation is the formation of new plants from vegetative parts like roots, stem, leaves or buds of the parent plants. Budding is of two types in plants as follows:
It occurs without help from humans. The fleshy leaves of certain plants like Kalanchoe daigremontiana or Bryophyllum daigremontianum bear adventitious buds in the marginal notches of the intact leaves. When these leaves fall on the ground, the buds develop into new plants.
Fig: Budding in Bryophyllum
Artificial budding is a grafting technique where only one bud from the desired scion (part gives rise to the upper portion) is used, as opposed to the entire scion which contains multiple buds. Most budding is done in plants just prior to or during the growing season. On the contrary, there are some species in which the budding can be done when they are in the dormant stage also. Examples of some ornamental plants in which budding is done are Hibiscus, rose, and holly plants. It can be done in some nut plants, such as almonds and chestnuts and fruit plants, such as cherry, peach, Citrus, and kiwi also.
Fig: Artificial budding
Budding is a process of asexual reproduction in which a daughter cell is produced as a protuberance from the parent cell.
Binary fission is a type of asexual reproduction in which a parent cell grows and divides into two halves. Each half grows and matures to form a new organism.
The daughter cell is smaller in size as compared to the parent organism.
The daughter cell and parent cell, both are equal in size and morphology.
The parent cell exists after the detachment of the daughter cell.
The existence of the parent cell is lost after reproduction.
Examples include yeast
Examples include Amoeba
Q 1. Identify the methods of asexual reproduction through which Hydra reproduces?
a. Binary fission
d. Both b and c
Answer: Hydra can reproduce through budding as well as fragmentation. In budding, Hydra develops an outgrowth by repeated cell division at one specific site on the parent organism. This outgrowth is known as bud. The bud grows and detaches from the parent body and becomes a new independent individual. On the other hand, in fragmentation, Hydra breaks into different pieces or fragments. Each fragment grows and becomes an adult. Hence, the correct option is d.
Q 2. Identify the process in the given image.
a. Budding in Hydra
b. Binary fission in Amoeba
c. Multiple fission in Amoeba
d. Budding in Yeast
Answer: Yeast reproduces asexually through a process known as budding. It reproduces by developing small outgrowths, known as buds, from their vegetative bodies. The nucleus of the parent organism divides and produces one daughter nucleus. This daughter nucleus is received by the bud and as a result, a small daughter cell and a large mother cell are formed. Sometimes the newly formed buds remain attached to the parent cell for a long time and this forms a chain of buds called pseudomycelium. The buds detach eventually from the parent cell and develop into new organisms. Hence, the correct option is d.
Q 3. The appearance of a little bud that detached from an organism's body to become a fully developed individual itself was discovered by scientists while studying on a creature in a lab. What kind of reproduction do you suppose the organism is carrying out here?
d. All of the above
Answer: In budding, a cytoplasmic perturbation occurs in the basal region of the parent body and forms a bud. The bud grows and develops by getting nutrition from the parent body. After some growth, the bud detaches from the parent body and develops into a new organism. Hence, the correct option is b.
Q 4. Identify the organism(s) in which reproduction occurs through asexual budding?
a. I and II
b. II and III
c. I and III
d. None of the above
Answer: Budding is a type of asexual reproduction that occurs in Hydra and yeast. A small outgrowth arises from the parent body which is called a bud. It slowly grows and detaches from the parent organism and forms a new individual organism. Planaria shows true regeneration. In this process a complete new individual is formed from a small body piece. Hence, the correct option is b.
Q 1. What is the significance of budding in yeast?
Answer: Budding in yeast is an important process to understand cell polarisation and symmetry. It helps the colony to establish itself in a substratum.
Q 2. Which type of cell division occurs during the process of budding?
Answer: During the process of budding, mitosis occurs. Mitosis is the process of nuclear division in which chromosomes replicate and become equally distributed into two daughters so that the daughter cells come to have the same number and types of chromosomes as are present in the parent cell.
Q 3. What are the disadvantages of budding?
Answer: Budding is an asexual mode of reproduction in which the offsprings produced are identical to the parent. Hence there is no genetic diversity. So it cannot lead to evolution compared to sexual reproduction.
Q 4. Why budding is important in terms of reproduction?
Answer: In most cases, a variety of plant that cannot be grown easily from seed is propagated through artificial budding. Therefore, budding is considered an important process in agriculture and horticulture. It occurs during unfavourable conditions in certain organisms. Examples include gemmule formation in sponges. It is the major method of reproduction in favourable conditions in certain organisms like Hydra.
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Life Span and Asexual reproduction, Practice Problems and FAQs
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