1. Title: Clones in nature
Homework: complete learning package 11 for Thursday
F215 – module 2
Biotechnologies and gene technologies

2. Learning Outcomes
Describe the production of natural clones in plants using the example of vegetative propagation in elm trees.
Describe the production of artificial clones of plants from tissue culture.
Discuss the advantages and disadvantages of plant cloning in agriculture.

3. Cloning Cloning is the production of genetically identical organisms
In plants cloning can occur naturally by asexual reproduction.
All cells are produced by mitosis from cells that were originally part of the parent plant
All plants are genetically identical to the parent plant and each other.

4. Asexual reproduction Advantages Disadvantages Quick
All offspring have the genetic information to enable them to survive in the environment
Disadvantages
No genetic variety
Does not allow for natural selection
Unable to adapt to environmental conditions.

5. Vegetative propagation
Asexual reproduction in plants is known as vegetative propagation
Examples
Strawberry plants produce runners
Potatoes form underground tubers
Daffodils produce bulbs
English Elm produces root suckers (basal sprouts)

6. Vegetative propagation in potatoes

7. English Elm The English Elm only reproduces by suckering
The growth of new trees from the roots or meristem tissue in the trunks
As all English Elms are genetically identical they are all susceptible to the fungus, Dutch elm disease

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12. Task Complete textbook questions on page 153
Mark your answers using the mark scheme at the back of the book
Extension: complete the stretch and challenge question

13. Artificial clones and agriculture

14. Artificial Vegetative propagation
It is possible to artificially propagate valuable plants
Taking cuttings – cut a section of stem between nodes, then treat with plant hormones to encourage root growth
Grafting – a shoot section of a woody stem is joined to a root stock
Tissue culture

15. Cuttings A node is a region of growth on a plant.
These small bumps can be seen where braches and leaves come off.
Cuttings are taken beneath the node and the cutting is dipped in rooting powder, containing synthetic growth hormones e.g. auxins to stimulate root growth

16. Grafting

17. Tissue Culture
Tissue culture allows for the production of huge numbers of genetically identical plants from a small amount of plant material.
All stages in tissue culture must be carried out in sterile conditions to prevent fungal infection

18. Stages in Plant Tissue Culture
A group of cells are removed from the parent plant called the explant.
Explant is placed on a nutrient growth medium
Cells divide to form a mass of undifferentiated cells called a callus
Single cells removed from callus and placed on a growth medium to stimulate shoot growth
The shoots are placed on a growth medium to stimulate root growth
Growing plants transferred to a greenhouse before planting outside

19. Plant Cloning in Agriculture
Desirable parent plant can be chosen and cloned
Plants mature at same time
In UK, Annual crops are propagated by seed
After years of inbreeding all crops are now genetically uniform
Even though seeds require sexual reproduction, all seeds and plants produced are genetically uniform

20. Plant Cloning in Agriculture
In perennial plants, the high cost of vegetative propagation is offset by
the long periods for which the plants stay in the ground
Relatively high value of the product
Examples
Lavender
Apple trees

21. Disadvantages of plant cloning
Susceptible to disease
Unable to adapt to climate change
Loss of genetic variation

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