PLANT TISSUE CULTURE: It's Techniques, Applications, Advantages and Disadvantages in Plant Biotechnology
Author: Cornelius Onye Nichodemus
Plant tissue culture is a collection of techniques used to sustain or grow plant cells, tissues or organs under sterile conditions on a nutrient culture medium of known composition. Plant tissue culture is used to produce clones of plant in a method called micopropagation. Plant tissue culture relies on the fact that many plant cells have the ability to regenerate into a whole plant in a process called totipotency. Single cells without cell walls (protoplasts), pieces of leaves, stems or roots can often be used to generate a new plant on culture media given the required nutrients and hormones. The plant part obtained from a plant to be cultured is called explant while the main plant it is obtained from is called mother plant. Explant can be taken from different plant parts such as shoots, leaves, stems, flowers, roots, single undifferentiated cells etc.
Preparation of plant tissues for tissue culture is performed under aseptic conditions under HEPA filtered air provided by laminar flow cabinet. The tissue is grown in sterile containers inside Petri dish, test tube or flasks in a growth room with controlled temperature and light intensity. Living plant materials are usually contaminated on their surfaces (or sometimes interior) with microorganisms, so their surfaces are stressed in chemical solutions (e.g alcohol and sodium hypochlorite). The sterile explant are placed on the solid and liquid media are generally composed of inorganic salts, organic nutrients, vitamins and plant hormones. Solid media are prepared from liquid media with the addition of gelling agent (agar). The composition of the medium, particularly the plant hormones and the nitrogen source have profound effects on the morphology of the tissues that grow from the initial explant. For instance, an excess of auxin will result in a proliferation of roots while an excess of cytokinin may yield to shoots proliferation. A balance of both auxin and cytokinin will often produce an unorganised growth of cells called callus, but the morphology of the outgrowth will depend on the plant species as well as the medium composition.
Plant tissue culture can be used widely in plant science, forestry and even in horticulture. They include:
1. Commercial production of plants used as landscape, potting and florist subject which uses meristem and shoot culture.
2. To conserve endangered plant species to avoid extinction.
3. To screen cells rather than plants for specific characters such as herbicide resistance/tolerance.
4. Use of meristem tip cultures to produce clean plant material from virus stock such as potatoes.
5. To produce disease free plants due to its production in sterile environment
6. For chromosome doubling and induction of polyploidy for example doubled haploid, tetraploids, and other forms of polyploids. This is usually achieved by application of antimitotic agents such as Colchicine or Oryzalin.
1. To quickly produce mature plants
2. The production of multiples of plants in the absence of seeds or pollinators to produce seeds
3. The production of exact copies of plants that produce particularly good flowers, fruits or have other desirable traits
4. The production of plants in sterile conditions with greatly reduced chances of transmitting diseases, pests and pathogens
5. The production of plants from seeds that otherwise have low chances of germinating and growing.
6. To mass propagate plants for commercial use.
7. It also produces disease-free plants due to its method of growth.
1. The setting up of a plant tissue culture laboratory is very expensive including it's machines and reagents
2. The experiments of tissue culture must be handled by highly trained people as the procedure requires special care and careful observations.
3. If all the plants are genetically similar, there is reduction in genetic diversity.
4. If a plant is susceptible to disease, all the plants of this cloned stock will share this undesirable trait and be susceptible to that particular disease.
5. The procedures depends on the type of species being cultured, hence there is need for trail and error method for any new species if there is no review about that species.
6. If precautions are not taken, the whole stock may be contaminated or infected.
About Author / Additional Info:
I am a First Class graduate of plant Science and biotechnology from University of port Harcourt, currently pursuing my masters in plant biotechnology.