1. 28 April 2017
HGS IGCSE
Cloning Plants

2. Flowering plants all reproduce sexually (that’s what flowers are for), but many can also reproduce asexually. Asexual reproduction uses vegetative (not reproductive) tissue, such as runners, bulbs, corms or tubers. Here are some examples.

7. Asexual Reproduction in Plants
Example: strawberry plants
The parent strawberry plant sends out runners - fast-growing stems that grow out sideways, just above the ground.
The runners take root at various points and new plants start to grow.
The new plants are clones of the parent plant – they are genetically identical.

8. Reproduction in plants
Copy and complete the table
Feature of the process
Sexual reproduction
Asexual reproduction
sex cells produced
fertilisation takes place
variation in offspring
has survival value in:

9. Reproduction in plants
Copy and complete the table
Feature of the process
Sexual reproduction
Asexual reproduction
sex cells produced
yes no
fertilisation takes place
variation in offspring
has survival value in:

10. Reproduction in plants
Feature of the process
Sexual reproduction
Asexual reproduction
sex cells produced
yes no
fertilisation takes place
variation in offspring
has survival value in:

11. Reproduction in plants
Feature of the process
Sexual reproduction
Asexual reproduction
sex cells produced
yes no
fertilisation takes place
variation in offspring
has survival value in:

12. Reproduction in plants
Feature of the process
Sexual reproduction
Asexual reproduction
sex cells produced
yes no
fertilisation takes place
variation in offspring
has survival value in:
changing environment
stable environment

13. What have these next four pictures
got in common?

18. They are all artificial clones

19. Cloning Plants using Artificial Methods
Cloning plants is useful to reproduce exactly desired characteristics, like flowers, fruit, vegetables, etc.
Plants are generally easy to clone, and there are two common techniques:
cuttings
micropropagation (tissue culture)

20. Cloning Geraniums from Cuttings
Fill a small pot with compost and make a small hole with a pencil.
Take a cutting of a geranium 3 joints below the top, cutting just below a joint using sharp scissors.
Remove all but the top two leaves and any flowers and buds.
Dip cut stem in rooting hormone and then stick into compost to a depth of about 2 cm.
Firm in, water and label.
Cover entire cutting with a clear plastic bag, secure bag to pot using an elastic band.
Leave on windowsill for a few weeks. Keep soil moist but not too wet.

21. Cuttings
Copy and fill in the gaps. New plants can be produced quickly and cheaply by taking _______ from older plants. These new plants are genetically _________ to their parents, so they have the desired ___________. Cuttings must be grown in ______ conditions until their _______ develop, or they will ____ through lack of water.

22. Cuttings
New plants cab be produced quickly and cheaply by taking cuttings from older plants. These new plants are genetically identical to their parents. This means that if cuttings are taken from a plant that has the characteristics you want, all the cuttings will have them as well. Cuttings are most likely to grow successfully if they are grown in damp conditions until their roots develop, so they are covered with plastic bags or sheets or put in special propagators.

23. Cloning Plants by Micropropagation
(or tissue culture)
Step 1
Remove tiny tissue samples from plant (explant)
Step 2
Grow in agar with plant hormones to stimulate growth

24. African violet culture started from leaf section.
Plantlets growing on agar

25. Rhododendron cultures

26. Growing plant cells in liquid culture
Planting out in soil

27. Begonia plants at various stages of micropropagation.

28. Micropropagation Key Science micropropagation (4min)
Nourse Micropropagation of berry plants (5min)
Timelapse of micropropagation
Kew Micropropagation
Zviely Date Palm Nursery Israel Website
Tour of a micropropagation lab (no narration)

29. Now write a method for carrying out micropropagation
Add notes to the diagram to describe the steps involved

31. What are the advantages of using micropropagation?
Large numbers of identical plants can be grown using micropropagation.
How does micropropagation differ from traditional methods of taking cuttings?
Give four advantages of micropropagation over traditional methods of propagation using cuttings.
Pages

32. 1. Comparing two methods of cloning plants
Cuttings
Micropropagation
Ancient technique
New technique
Few clones per plant
Very many clones per plant
Cheap equipment
Expensive equipment
Seasonal
Year round
Doesn’t work for all plants

33. 2. Advantages of micropropagation
Large numbers of genetically identical plants produced rapidly.
Method can be used in species that are difficult to grow from seed or cuttings.
Plants can be produced at any time of year.
Large numbers of tiny plants can be stored easily (can be kept in cold storage until needed)
Genetic modifications can be made in a small number of plants which then give thousands of plants carrying the desired characteristic.