What is Tissue Culture?
Tissue culture is a technique in which fragments of plant or animal tissues are cultured and grown in a laboratory. Many times the organs are also used for tissue culture. The media used for the growth of the culture is broth and agar.
This technique is also known as micropropagation. It has proved beneficial for the production of disease-free plants and increase plant yield in developing countries. It only requires a sterile workplace, greenhouse, trained manpower, and a nursery.
Oil palm, banana, plantain, eggplant, pineapple, rubber tree, tomato, sweet potato have been produced by tissue culture in the developing countries.
There are two main types of cultures:
Primary Culture– It consists of normal tissues excised from the living organisms by biopsy. They model the natural function of the tissue. These cultures are generally mortal.
Cultures of established Cell Lines– These are either derived from the tumour biopsies, or from the primary cells that had undergone mutation and continued to replicate.
Types of Tissue Culture
Following are the different types of tissue culture techniques:
In this culture, the explants are obtained from an in-vitro derived plant and introduced into a laboratory where they proliferate. The explant should be sterilized to prevent it from tissue damage.
This involves the in-vitro development of an embryo. For this, an embryo is isolated from a living organism. Both, a mature or an immature embryo can be used in the process. Mature embryos can be obtained from ripe seeds. The immature embryos are obtained from the seeds that failed to germinate. The ovule, seed or fruit is already sterilized, therefore, it does not need to be sterilized again.
A callus is an unorganized, dividing mass of cells. When the explants are cultured in a proper medium, the callus is obtained. The growth of callus is followed by the organ differentiation. The culture is grown on a gel-like medium composed of agar and specific nutrients required for the growth of the cells.
In this, any organ of the plant such as shoot, leaf, can be used as an explant. A number of methods can be used for the organ culture, such as plasma clot method, raft method, grid method, and agar gel method. This method is used to preserve the structure and functions of an organism.
It is a cell without a cell wall. A protoplast can be cultured using the hanging-drop method, or micro-culture chambers. In protoplast culture, a number of phases can be observed: development of cell wall, cell division, regeneration of a whole plant.
Single Cell Culture
Steps of Tissue Culture
The steps of tissue culture are given below:
At this stage, the tissue is initiated into the culture. The tissue of interest is obtained, introduced and sterilized to prevent the process from any contamination.
In this stage, the sterilized explant is introduced into the medium composed of growth regulators and appropriate nutrients. They are responsible for the multiplication of cells. This undifferentiated mass of cells is known as callus.
The roots start forming. Plant growth hormones are added to initiate the root formation. Consequently, we obtain complete plantlets.
The plant growth hormones for the formation of shoot are added and the growth is observed for a week.
When the plant starts developing, it is transferred to the greenhouse to develop under controlled environmental conditions. It is finally transferred to the nurseries to grow under natural environmental conditions.
Advantages of Tissue Culture
Following are the various advantages of tissue culture technique:
The plantlets are obtained in a very short time with a small amount of plant tissue.
The new plants produced are disease-free.
The plants can be grown throughout the year, irrespective of the season.
A large space is not required to grow plants by tissue culture technique.
The production of new varieties in the market place speeds up.
This technique is being used for the production of ornamental plants such as dahlia, chrysanthemum, orchids, etc.
Importance of Tissue Culture
Tissue culture is very important in biology due to its wide range of applications.
Both plant and animal tissues can be used for culturing. For eg., animal tissue culture helps in preserving an organ or tissue.
Plant tissue culture may be used for genetic modification of a plant or simply increase its yield. the cells of the plants can be genetically altered to produce plants with desirable characteristics.
This technique utilizes the plant’s ability to rejuvenate the tissues rapidly. It produces exact copies of itself known as clones.
It is a technique of quickly producing plants without any tubers, seeds or bulbs.
It also helps in the conservation of plant biodiversity by the production of endangered plants.
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