An Overview of Tissue Culture: What It Is and How to Get Started

 Planting any living part of a plant in an artificial culture medium in a sterile environment under controlled conditions such as temperature, light, humidity, etc. is tissue culture.

Even a single living cell of a plant has the potential to grow into a complete plant. It is called totipotency.

Sections used for tissue planting.

⦁ Stem Apical Bud, Lateral Bud, Root Apex,

⦁ Seeds, embryos, anthers

⦁ Leaf fragments, root fragments, live stem parts

⦁ protoplast

⦁ apical meristem

Tissue culture is done in several ways. One method is tissue culture using buds. This method is used if it is necessary to obtain a large number of plants similar to the mother plant in a short period of time.

                                        ex- pineapple, Strawberry, orchid, banana, anthurium, bamboo 

The other method is tissue culture using meristems. Generally, if a virus-infected plant shoot is taken and planted, it will also be infected with the virus. But by planting under this method, many virus-free plants can be obtained. A plant's apical meristem is healthy because the rate of cell multiplication in the apical meristem is much greater than the rate of virus multiplication.

If an infected area of ​​a plant is examined after a few days, it can be seen that there is an irregular cluster of cells. This irregular collection of cells is called callus. Callus can be induced by stimulation of plant growth hormones called auxins and cytokinin in tissue culture techniques. Also, this callus can produce shoots, plants and roots. And sometimes uneven changes can occur in the plants. Therefore, there is a variety of crops. This planting method is called callus culture and it is important to produce new plant species in genetic engineering. The last one is embryo culture.

An embryo is created when plants are hybridized. But due to the incompatibility that occurs in distant plant breeding, those embryos die. In this case, the embryos can be separated from the seed before maturity and planted in an artificial culture medium to obtain plants. Thus, embryos that are destroyed by this method can be saved.

Phases of Micropropagation

⦁ Selection of mother plant

The mother plant selected here should have healthy and important characteristics. If necessary, a DNA test can be done to find out if there are relevant characteristics. And whether the plant parts are virus free can be confirmed by ELISA test.

⦁ Explant establishment

If the explant is not obtained from a properly maintained plant house, fungicide or antibiotic spraying should be done the day before explant is obtained. The explant obtained in this way should be immersed in a container of water or a warm polythene bag and brought to the laboratory to prevent drying. In the laboratory, these parts should be washed thoroughly with Distilled water and 10cm parts should be separated and sterilized.

1. Wash the buds well under running water.

2. Wash in 70% alcohol for about five seconds

3. Sterilize the buds by shaking well for 10-30 minutes with a chemical like Sodium hypochlorite, Calcium hypochlorite

In this case, if left immersed in these solutions in high concentration or for a long time, the tissue may dissolve and be destroyed. Finally, wash well with distilled water and put this bud in a sterile petri dish or beaker and cover it. A Laminar flow cabinet with a sterile environment is used to inoculate these buds into the medium.

⦁ shooting stage

At this stage, the shoots obtained by explant establishment are separated. This is called superimposition. This is the main stage of obtaining a large population of plants by micropropagation. Fertilization increases the number of plants and frequent fertilization can lead to tissue weakness called vitrification. Cytokinin is the most important hormone for shooting stage.

⦁ rooting stage

Here, the above multiplied plants are transferred to a medium without Cytokinin and deposited. Auxin group hormones such as IAA, IBA and IBA are used here. Sometimes the effect of Cytokinin is reduced by adding 0.2% of activated charcoal. In this case, in 2-6 weeks, you can see well-developed roots and well-struck leaves.

⦁ Hardening stage 

Planting well-rooted plants in the external environment is the main objective. But since the conditions of the external environment are significantly different from the laboratory conditions, it is not possible to directly introduce them to the external environment. For that there is a process of acclimatization of plants.

Remove the plants from the planting medium and wash the roots with warm water. Immerse in a compound fungicide for about five minutes and remove. Plant in potting medium containing sterile sand or coir. Then these plants should be covered with polythene. Propagator can be used for that purpose. Thus, by providing 100% humidity and 50% shade, it can be gradually reduced after about a week and after about 4-8 weeks, it can be planted in the normal environment. After doing this, it is advisable to use a liquid fertilizer after new shoots or leaves come.

Advantages of micro propagation

⦁ Being able to get plants in a very short time from a healthy mother plant.

⦁ A large number of plants can be obtained in this short time.

⦁ No effect of external environmental conditions such as rainfall, drought conditions

⦁ Disease-free plants can be obtained.

⦁ Conservation of endangered plants through conservation of genetic resources.

⦁ Being able to produce plants similar to the mother plant.

Disadvantages of tissue culture

1. Expensive as a laboratory is required

2. An infestation can destroy a large plant population.

3. Technical knowledge required

4. There is a risk of mutations.

5. vitrification