1. Propagating and growing plants
Unit 2 Key Area 2.2
Propagating and growing plants

2. Propagation Learning Intention: Success Criteria:
To learn about the different methods of propagating plants.
Success Criteria:
To understand what the different types are.
To carry out the techniques with various plants.

3. Starter Activity: Question
Thinking time: 2 mins
Can you decide with your partner three different ways in which we can grow plants?

4. What is propagation?
Vegetative propagation means the ways that plants can make copies of themselves without making seeds.
Gardeners use vegetative propagation to increase the numbers of a plant.
Propagated plants have identical characteristics to the “parent” plant.

5. Artificial Propagation
Gardeners can make new plants in a way that the plant is unable to do naturally.

6. Examples of Artificial Propagation
Cuttings- part of a plant is cut off to produce a new identical plant.
Layering- part of a stem is encouraged to grow roots to produce a new identical plant.

7. Cuttings Gardeners can take cuttings from plants.
Cuttings grown in water can then be planted in soil or compost once roots have grown.
Stem cutting placed in water.
2 weeks later roots have grown.

8. Growth points Growth points are where stems branch.
They are also called nodes.
Cuttings are taken just below nodes.

9. Activity 1: Taking your own cuttings
Cut the stem below a node.
Remove 2 or 3 leaves from the bottom of the stem. This reduces water loss from the cutting.
Place in a beaker of water or damp compost, and water regularly.
Rooting powder can be used to speed up root growth.
Place in a propagator or cover with a plastic bag or bottle for one week.

10. Taking a Cutting
Taking a cutting from a geranium

11. Reducing water loss
A new cutting loses water through its leaves but doesn’t have any roots to take up more water.
Gardeners remove lower leaves from a cutting to reduce water loss.
A bag can also be placed around the plant. This makes the air around the
plant humid (damp).

12. Layering Learning Intention: Success Criteria:
To learn about the different methods of propagating plants.
Success Criteria:
To understand what the different types are.
To carry out the layering technique.

13. Starter
Time: 5 minutes
Re-order the steps of taking a cutting.

14. Layering
Layering is a way of propagating plants by getting a normal stem to grow roots.
Layering is often used for plants like ivy with long flexible stems.

15. Activity 2: Layering your own plant
A long stem is selected from the parent plant.
A small cut is made on the underside of the stem at the node. This area is then dusted with rooting powder.
The stem is pegged down in contact with the soil.

16. Propagators
A propagator is a piece of equipment that provides a warm, humid atmosphere for raising young plants such as stem cuttings.
Plastic bags and bottles can be used as simple propagators.

17. Quick questions What is artificial propagation?
Give an example of an artificial propagation method.
What is a node?
Explain why the bottom leaves are removed when taking cuttings.
What chemical is used to speed up the development of roots on a cutting?
Give two ways in which water loss can be reduced when taking cuttings.

18. Answers
Ways in which plant growers increase the number of plants using methods plants cannot use.
Taking cuttings or layering
A point on a stem from which leaves or side branches grow. (A growing point)
To reduce water loss from the cutting.
Rooting powder
By placing the cuttings in a polythene bag, plastic bottle or propagator. By removing lower leaves.

19. Natural Propagation Learning Intention: Success Criteria:
To learn about the different methods of propagating plants.
Success Criteria:
To understand what natural propagation is.
To carry out planting a bulb.

20. Natural Propagation
Vegetative propagation can be natural - the plant will make copies of itself using various structures.
Examples:
Bulbs- daffodils
Tubers- potatoes
Plantlets- Mexican hat plant
Runners- spider plant
Offsets- mother-in-law’s tongue

21. Natural vegetative propagation - bulbs
Bulbs are leaf bases, swollen with food and are called food storage organs (usually Starch)
The leaves may die back each winter, but the bulbs will grow into new plants the following spring
The bulbs may make daughter bulbs - so each year, more plants may grow.
e.g, Daffodil bulbs. The plant on the right has grown a daughter bulb.

22. Natural vegetative propagation - tubers
Similar to bulbs, tubers are underground stems or roots that are swollen with food, so are also food storage organs (usually Starch)
Each tuber can grow into another plant the next year, using food stored in the tuber to start it off
New potato plant growing from one of last year’s tubers. New tubers will form on underground stems.

23. Activity 4: Dissecting a bulb
Remove the papery bulb coat.
Cut the bulb half.
Add a drop of iodine solution to the bulb.
stem
Papery protective coat
roots

24. Activity 5: Growth of the Bud
When a bulb has grown green leaves above ground, a daughter bud can grow under the ground. This can form a new plant.
Stem
Daughter
bud
grows
into
new plant
Side
bud

25. Describe what natural propagation is.
On a post it note…
Describe what natural propagation is.
Leave this on your desk

26. Natural Propagation Learning Intention: Success Criteria:
To learn about the different methods of propagating plants.
Success Criteria:
To understand what natural propagation is.
To carry out planting a plantlets.

27. Runners
A runner is a horizontal stem with plantlets at intervals along its stem. A good example of a runner is the spider plant.
The plantlets can be pegged down until roots develop
Spider plant with plantlets
on the end of runners

28. Offsets
Offsets are small plantlets produced as a side shoot at the base of the parent plant.
These are mainly found in cactus plants.
Cactus with multiple offsets

29. Leaf edge plantlets
This Mexican hat plant has produced plantlets at the edge of its leaves. They will drop off, grow roots and grow into new plants.

30. Quick Questions
Name two food storage organs that are natural plant propagation structures
What kind of food storage organ does a potato plant produce?
What kind of food storage organ is an onion?
What method of propagation is used by the Mexican hat plant?

31. Answers
Bulbs and tubers
Tuber
Bulb
Leaf edge plantlet

33. Label the type of plantlet being removed from the parent plant

34. Dissecting Seeds Learning Intention: Success Criteria:
To learn about the different methods of propagating plants.
Success Criteria:
To understand what natural propagation is.
To carry out a dissection of a seed.

35. Growing plants from seeds
Thinking time- 1 min
What are seeds?
Where do they come from?

36. Where do seeds come from?
FRUIT!!

37. Where does fruit come from?
Flowers!!

38. So seeds are made by the flowers of plants

39. Seeds
Seeds are the offspring of the plant – they can be planted to produce more of the same plant
This is an example of sexual reproduction.

40. Seed Structure Seeds contain an embryo and a food store.
Seeds are covered by a tough seed coat.
Broad bean seed - opened up
Food store
Seed coat
Embryo plant

41. Activity 5 – Dissecting a seed
Peel off the seed coat of your broad bean.
Split the seed in half.
Identify the embryo.
Put a drop of iodine solution on the seed.

42. Quick Questions 1. What is the function of the seed coat?
2. What colour did the iodine solution turn?
3. What type of food makes up the food store?
4. What happens to the food store when the seedling starts grow?

43. Answers Protects the seed Blue/Black Starch
It is used as food for the growing seedling

44. Label your drawing of a seed

45. Seed structure
Food store
Seed coat
Embryo shoot
Embryo root

46. Functions of seed parts Match up the correct seed part with its function, and complete the table in your booklet.
Part of seed
Function of part
Embryo root
To grow into the plant’s shoot
Embryo shoot
To protect seed from damage by soil micro-organisms
Food store
To grow into the plant’s root
Seed coat
To provide energy for growth of embryo root & shoot

47. Dissecting Seeds Learning Intention: Success Criteria:
To learn about the different methods of propagating plants.
Success Criteria:
To understand what natural propagation is.
To carry out a dissection of a seed.

48. Planting Seeds Learning Intention: Success Criteria:
To learn about the different methods of propagating plants.
Success Criteria:
To understand what natural propagation is.
To carry out planting of large and small seeds.

49. Starter

50. Germination
Germination is the development of a plant embryo inside a seed into an independent plant with green leaves.
During germination, the food store present in the seed is digested and used up to give the young plant energy for growth.

51. Sowing Large Seeds Seeds must not be sown too close together.
Large seeds (such as acorns or beans) can be sown individually, spaced out by hand.

52. Sowing Small Seeds
Smaller seeds can be mixed with silver sand before sowing.
The silver sand “dilutes” the seeds so that they can be spread more thinly.

53. Activity 6: Planting seeds
Small Seeds
Select a clean seed tray or plant pot and fill with seed compost.
2. Level the compost and firm gently.
3. Mix the seeds with silver sand if they are very small. Scatter the seeds thinly and evenly over the surface of the compost.
4. Cover the seeds evenly with a thin layer of sieved compost.
5. Firm gently.
6. Use a watering can with a fine rose to water your seeds.
7. Use a pencil to write your name, date, type and variety of seed on a plant label.
8. Cover the tray or pot with a clear plastic sheet.

54. Activity 6: Planting seeds
Large Seeds
Fill the tray with compost.
Firm the surface of the compost.
Sow the seeds individually pressing them into the compost.
Cover them over with compost.
Use a watering can with a fine rose to water your seeds.
Use a pencil to write your name, date, type and variety of seed on a plant label.

55. Germination Investigation
Learning Intention:
To learn about the different methods of propagating plants.
Success Criteria:
To understand what natural propagation is.
To carry out an investigation into the conditions for germination.

56. Rules of an investigation
Only one variable should be studied at a time why?
Good sample size…….why?
The experiment should be repeated several times……why?

58. Conditions
Test tubes 1 2 3 4 5
Light  x
Water
Oxygen
Warmth

59. Results Test Tube Condition lacking Number of seeds germinated (?/10)
% germination 1
None 2
Water 3
Oxygen 4
Light 5
Warmth

60. Conclusion The conditions required for successful germination are:
______________

61. Conclusion The conditions required for successful germination are:
Water
Oxygen
Warmth