Micropropagation is a tissue culture method that is used for rapid vegetative propagation of plants under sterile conditions. Plant tissue culture is a technique of growing ste/rile conditions of plant cells, tissues or organs on an artificial medium in special containers under controlled environmental conditions. Explant is the part of the plant that grows under these conditions. Tissue cultures use the ability of a plant to regenerate an entire plant from each cell / explant (cellular totipotency). Single cells, cells without cell walls (protoplasts), pieces of leaves, stems or roots, embryos, fruits and more. are used as explants and can give a new plant.
What do we need to grow in vitro plant explants?
- Nutrient medium: The composition of the nutrient medium for plant tissue should provide everything necessary for cell growth and is highly dependent on the type of plant tissue or cell being grown. The nutrient medium contains inorganic salts (macro and micro salts), an energy source (usually sucrose), vitamins (eg thiamine, myoinositol), amino acids and growth regulators (plant hormones-auxins, cytokinins, gibberellins). Optimal pH of the medium (most often pH 5.7) is very important.
The nutrient medium may be liquid or solid. A gelling agent-agar (a polysaccharide derived from the red alga Gelidium amansi) is usually added to solidify the medium.
- Sterile Conditions (Sterilization): The nutrient medium contains sugar which increases the growth of microorganisms (bacteria and fungi). These germs compete with plant tissues and can eventually kill them, so it is important to maintain sterile tissue culture conditions. The plant material must initially be surface sterilized so that all bacteria and spores of the fungus are removed. The aim is to kill all microorganisms without seriously damaging the plant material.
Sterile explants are transferred to sterile culture media in suitable sterile air vessels in laminar boxes (providing HEPA-filtered air).
- Growing conditions: Tissue cultures are grown in growth chambers or phytostat rooms under controlled conditions of temperature and humidity and artificial light.
Application of plant tissue cultures
Micropropagation is a tissue culture method that is used for rapid vegetative propagation of plants under sterile conditions. The method is preferred for many species that are difficult and slow to reproduce by traditional methods. Each plant obtained by micropropagation is genetically identical to the original plant from which it originated. The propagated plants, when well rooted, are removed from the sterile vessels. Then they transferred to pots under controlled but not sterile conditions to be acclimatized and subsequently planted in the field.
Advantages of micropropagation:
- Fast multiplication of plants in a short time and in a small place
- Produced plants under controlled conditions, regardless of the seasons
- This method propagates sterile plants or plants that cannot retain their sexual reproduction characteristics.
- Te method saves from extinction rare and endangered plant species as it multiplies them.
- Production of virus-free plants such as potatoes, cane, bananas, apples and more. for horticulture and agriculture.
If we sum up:
- Large-scale cultivation of plant cells in liquid media in bioreactors to produce valuable pharmaceutical compounds.
- Fusion of protoplasts of distant plant species and obtaining new hybrids.
- Fast in vitro selection of stress resistant plants – salinization, drought, low temperatures, high temperatures, heavy metals, herbicides.
- Regeneration of whole plants from genetically modified plant cells.