Unit 2 Key Area 2.2

1. Unit 2Key Area 2.2 Propagating and growing plants

2. Propagation Learning Intention: 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. Stem cutting placed in water. Cuttings • Gardeners can take cuttings from plants. • Cuttings grown in water can then be planted in soil or compost once roots have grown. 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: 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: 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. On a post it note… Describe what natural propagation is. Leave this on your desk

26. Natural Propagation Learning Intention: 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 Spider plant with plantlets on the end of 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

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

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 partsMatch up the correct seed part with its function, and complete the table in your booklet.

47. Dissecting Seeds Learning Intention: 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: 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.