Plant cloning
- Created by: Steff06
- Created on: 29-02-16 19:47
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- Plant Cloning
- Asexual reproduction:
- Advantages:
- Only requires 1 plant so FAST process as no need to find a mate. All offspring have the same genetic information so will be WELL ADAPTED to their environment.
- Disadvantages:
- LACK of genetic VARIATION, so cannot evolve or adapt to change. 1 disease may wipe entire population out.
- Advantages:
- Natural vegetative propagation:
- Tubers e.g. potato, root suckers/basal sprouts e.g. Elm trees, runners e.g. strawberries, bulbs e.g. daffodils.
- Asexual reproduction in Elm trees:
- Happens following damage/stress to parent tree. New growth in form of ROOT SUCKERS/ basal sprouts from meristem tissue in trunk close to ground within 2 months. Suckers all round trunk - Clonal patch which in turn put out suckers. Clonal patches - initially still roots connected to a tree.
- Problems: DUTCH ELM DISEASE. This devastated populations of Elm trees in Europe. Caused by a FUNGAL PATHOGEN spread by the Elm bark beetle. Fungus accidentally introduced from Asia.
- Ways disease can spread:
- Roots spread, insects, Tree surgeon contamination.
- Artificial vegetative propagation:
- 1. Taking CUTTINGS, 2. GRAFTING - SCION not genetically identical to root. 3. TISSUE CULTURE.
- Taking cuttings:
- 1. Take section of stem cut between leaf joints (nodes).
- 2. Cut end is dipped into rooting powder which contains plant hormones (AUXIN) to encourage growth.
- 3. Planted where it should start to develop roots and leaves.
- Tissue culture:
- 1. The leaf cells explant are taken from meristems in the shoot tips with sterile forceps.
- 2. Plant sterilised by dipping intto bleach so no plants will be infected.
- 3. Section of cells transferred to nutrient agar containing nutrients e.g. potassium, magensium, glucose which assist in plant's growth.
- 4. Cells are subdivided from callus culture and placed in agar which will stimulate shoot growth through use of hormone e.g. auxin.
- 5. Plantlets transferred into agar containing root stimulating hormones e.g. cytokinin and auxin where plantlets will differentiate.
- 6. Plantlets planted into compost/soil/greenhouse in aseptic conditions and grow into larger plants with same genetic information.
- Micropropagation:
- Advantages:
- Quick, produce a large amount, not reliant on environment so done anywhere, genetically identical, disease free,.
- At same point of growth, useful for rare/endangered species, uniformity makes marketing easier, shipped in large numbers.
- Quick, produce a large amount, not reliant on environment so done anywhere, genetically identical, disease free,.
- Disadvantages
- Time consuming, expensive e.g. to maintain temperature, need lots of space, no genetic variation, requires sterile facilities + trained staff, susceptible to disease.
- Advantages:
- Asexual reproduction:
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