Application:
• Micropropagation of plants using tissues from the shoot apex, nutrient agar gels and growth hormones
Micropropagation is a technique used to produce large numbers of identical plants (clones) from a selected stock plant
- Plants can reproduce asexually from meristems because they are undifferentiated cells capable of indeterminate growth
- When a plant cutting is used to reproduce asexually in the native environment it is called vegetative propagation
- When plant tissues are cultured in the laboratory (in vitro) in order to reproduce asexually it is called micropropagation
The process of micropropagation involves a number of key steps:
- Specific plant tissue (typically the undifferentiated shoot apex) is selected from a stock plant and sterilised
- The tissue sample (called the explant) is grown on a sterile nutrient agar gel
- The explant is treated with growth hormones (e.g. auxins) to stimulate shoot and root development
- The growing shoots can be continuously divided and separated to form new samples (multiplication phase)
- Once the root and shoot are developed, the cloned plant can be transferred to soil
Micropropagation
Application:
• Use of micropropagation for rapid bulking up of new varieties, production of virus-free strains of existing
varieties and propagation of orchids and other rare species
Micropropagation is used to rapidly produce large numbers of cloned plants under controlled conditions:
Rapid Bulking
- Desirable stock plants can be cloned via micropropagation to conserve the fidelity of the selected characteristic
- This process is more reliable that selective breeding because new plants are genetically identical to the stock plant
- This technique is also used to rapidly produce large quantities of plants created via genetic modification
Virus-Free Strains
- Plant viruses have the potential to decimate crops, crippling economies and leading to famine
- Viruses typically spread through infected plants via the vascular tissue – which meristems do not contain
- Propagating plants from the non-infected meristems allows for the rapid reproduction of virus-free plant strains
Propagation of Rare Species
- Micropropagation is commonly used to increase numbers of rare or endangered plant species
- It is also used to increase numbers of species that are difficult to breed sexually (e.g. orchids)
- It may also be used to increase numbers of plant species that are commercially in demand