[Biology Class Notes] on Bud Pdf

While doing a study of the anatomy of plants, we come across an undeveloped or embryonic shoot that normally occurs in the axil of a leaf or at the tip of a stem, which is known as bud. After the formation of buds in plants, it remains in a phase of dormancy for a certain period of time but sometimes they also get converted into shoots immediately. 

 

Their main specialization is to get converted into a shoot or flower depending on the need or type of plant. They arise on the stem of the vascular plant and further develop into flower, leaf or shoot. The major origin point of bud is meristem tissue. 

 

Trees that mainly grow in temperate climates form resting buds have the capability to frost in preparation for winter.

Types of Bud

Based on the growth of buds we can identify plants especially in woody plants in winters when leaves have fallen. 

 

Classification of buds can be done based on different factors like location, status, morphology and function: 

1. Buds Based on Location

1. Terminal Buds:  When the bud is located at the tip of a stem 

2. Axillary Bud: When the bud is  located in the axil of a leaf

3. Adventitious Bud: When the bud is  occurring elsewhere like on the trunk or on roots 

2. Based on Status

1. Accessory Bud:  These are secondary buds formed besides a principal bud

2. Resting Bud: Buds that are grown at the end of a growing season, which will lie dormant until the onset of the next growing season. 

3. Pseudoterminal: They are a kind of an axillary bud taking over the function of a terminal bud 

3. Based on Morphology

1. Scaly Buds: When scale covers the embryonic part for protection work. 

2. Hairy Buds: When there is a hairy appearance for protection.  

4. Based on Function

1. Vegetative Bud: If buds containing vegetative pieces like embryonic shoot with leaves

2. Reproductive Bud: Bud which contains embryonic flowers. 

3. Mixed Bud: When buds have both embryonic leaves and flowers.

What is Budding?

It is an asexual mode of reproduction for producing a new organism. Under this process, a new organism is formed from a small part of the parent’s body. After bud formation, they detach themself from their parent body to develop into new individuals. As bud formation is a kind of asexual reproduction, so the newly formed individual is a true replica of its and is also genetically similar to their parents. The separation from the parent organism happens when the bud gets matured by leaving scar tissues behind. As this is asexual reproduction, the newly developed organism is a replica of the parent organism and is genetically identical.

 

One of the common examples of budding is seen in hydra, as they use their regenerative cell where bud expands as an outgrowth as there is repeated cell division at a specific location of the plant. Further, these buds develop into new individuals, which get detached from the parent body after attaining complete maturity. Along with hydra yeast also shows a budding process. 

Example of Budding

Budding is commonly seen in both unicellular and multicellular organism and it is an asexual mode of reproduction. Some organisms which undergo budding processes are bacteria, yeast, corals, flatworms, Jellyfish and sea anemones. 

 

Yeast also reproduces with budding, as it is a non-green single-celled microorganism of kingdom fungi and their size is generally larger than bacteria. In yeasts, budding processes only occur when there is an abundant supply of nutrition. A very small bud arises from the parent body which leads to the separation of parent yeast into two parts and one of the nuclei gets shifted to bud. At last, a newly created bud detaches itself from the parent body and gets developed into new individuals. 

Budding in Hydra

Hydra is considered to be a freshwater organism, with a length of just centimeters found in tropical regions. It is known for its regenerative ability. It belongs to a Cnidarian family with a tubular shaped body made up of a head, distal and a foot at the end part. In hydra, a small bud develops from the parent body through a repeated mitotic division. This small bud receives all kinds of nutrition from the parent body and grows. The growth of the new hydra starts with tentacles and the month. Tentacles and the mouth develop in the early stage. As the bud slowly develops and reaches towards maturity, after attaining maturity, the newly formed hydra detaches themself from their parent body and develops into new individuals.

 

Budding in Yeast

Yeast is a single-cell organism which needs food, warmth and moisture to survive. It is classified as a member of the fungus kingdom. It converts sugar and starch into carbon dioxide and alcohol through the process of fermentation. Yeast reproduced asexually with a process called budding, which is an asymmetric division process.

 

In yeast, budding usually happens when they have an abundant supply of food and nutrition. During reproduction, a small bud grows from the part of the parent body. And then the parent’s nucleus yeast splits into daughter nucleus and transferred to the daughter yeast cell. After some time this new bud separates from the parent body and grows into a new yeast cell.