Production of Artificial Clones in Plants
Cultivars
- Gardeners and horticulturalists can harness the natural processes of vegetative reproduction to form the basis of artificial cloning
- Techniques such as cuttings, layering, grafting, division and budding have been used
- This creates cultivars, strains of genetically identical plants that can endure as foodstuffs or commercial blooms for many years
- All methods rely on the formation of meristematic tissue from which plant organs can differentiate
Micropropagation and tissue culture
- Many plant cells are totipotent, unlike animal cells, and therefore an entire plant can be reproduced from any of these cells
- Creating clones of cauliflowers is used to demonstrate totipotency through the production of tissue culture
- Cauliflower is used because it is comprised mostly of actively dividing cells and can withstand being handled
- A small piece of the plant is cut, this is called an explant, which is then grown into a new clone of the original plant
- Care must be taken to disinfect the explant and to use aseptic techniques to avoid fungi from colonising the growth medium and causing the micropropagation to fail
- This technique is used by scientists to reproduce endangered species of plants where relatively little source material exists
Apparatus
- Eye protection
- Disinfectant (usually a bleach solution)
- Sterilising solution
- Scalpel
- Gloves
- Forceps
- Cauliflower
- Agar growth medium containing sterilant
- Container
- Marker pen
Method
- Wear eye protection at all times
- Wipe all surfaces with disinfectant and soak all apparatus in sterilant
- It is important to ensure a sterile environment so that no fungi contaminate the experiment, which would result in seeing a fungal growth rather than an explant growth
- Break off a small floret of cauliflower from the plant then using a scalpel, cut a thin section of the floret (about 5-10mm long)
- This thin section is the explant
- Sterilise the explant by soaking it in sterilising solution for 15 minutes, swirling the explant around within the solution every 5 minutes
- This ensures that the explant is sterile and therefore only cauliflower cells are present
- Take out the explant using sterilised forceps and add it to a container of agar growth medium
- The growth medium contains all the nutrients that the plant needs for growth and also contains a sterilant to ensure no contamination occurs throughout the experiment
- Leave the container holding the agar growth medium and the explant on a sunny windowsill for 3 weeks
The steps of micropropagation of a cauliflower from an explant
Results
- The result of this experiment is to grow a complete cauliflower clone from an explant
- This shows that the cells in the explant have the capability to produce all the different cell types that make up a full cauliflower plant, hence they are totipotent
- The complete cauliflower plant can then be distributed to commercial growers/garden centres in large numbers
