1. S4 Biology UNIT 2: Multicellular organisms
Plants

2. Growing plants

3. Growing plants Learning intention:
Describe different methods of growing plants.
Why?
Plants are an important resource, it is important to understand how to grow them.

4. Growing plants We can grow plants using many different methods.
How can we grow plants?
Can you think of any different methods?

5. Growing plants Today we are going to discuss growing plants by: Seeds
Bulbs
Tubers
Runners
Cuttings

6. Seeds The easiest way to grow plants is using seeds.
It is important to read the information on the seed packet to make sure the seeds are being planted correctly.
What factors do you think a seed needs to grow?

7. Seeds
It is important that seeds are sown properly to ensure they will grow well.
What could happen if seeds were not sown properly?

8. Sowing seeds Some seeds such as pumpkin seeds are quite large.
How would they be sown?
Why are they sown this way?

9. Sowing seeds Some seeds such as carrot seeds are very small.
How would they be sown?
Why are they sown this way?

10. Seeds
Once a seed has been planted and given the correct conditions, it will begin to germinate and develop into a new plant.

11. Bulbs and tubers
Most plants use seeds to make new plants and this requires two plants.
Bulbs and tubers are a type of asexual reproduction
This means that only one parent is involved in reproducing new plants.

12. Bulbs and tubers An example of asexual reproduction is a bulb.
Bulbs store food.
New plants will grow from buds contained in a bulb given the correct conditions.

13. Bulbs and tubers
A tuber is a second example and is an underground stem which also has a foodstore.
The following year a new plant can sprout from it.
A potato is an example of a tuber full of stored food in the form of starch.

14. Bulbs and tubers
Both bulbs and tubers involve only one parent plant in producing new offspring.
Therefore they are both examples of asexual reproduction.

15. Runners
Some plants produce plantlets at the end of long stems that ‘run’ along the ground.
The plantlets will get food and water from the ‘parent’ plant until they have grown roots into the soil.
Then the stem will wither away and the plantlet will grow on its own.

16. Runners on a ‘mother-of-thousands’.
Runners on a ‘spider plant’.

17. Cuttings Gardeners can take cuttings from plants.
The plants will re-grow roots if the cut end is put in moist compost or water for a couple of weeks.
Rooting powder can be put onto the cut end to encourage root growth.

18. Stem cutting placed in water.
Two weeks later it has grown roots.

19. Cutting Cuttings can be taken from the leaf of a plant or the stem.
We are going to carry out a stem cutting from a geranium plant.

20. 1. Collect a geranium plant.
2. Use the scissors to take a cutting from the plant, making sure it is a growing plant.

21. 3. Fill the plant pot with compost to within 1cm of the rim.
4. Cut the stem just below a pair of leaves using scissors.

22. 5. Remove the lower leaves from your ‘cutting’.

23. 6. Dip the base of the cut stem into rooting powder.
7. Make a small hole in the centre of the compost. Place your cutting into the hole and firm it in gently using your fingers.

24. 8. Water the cutting to dampen the compost.
9. Label pot with your name, date and plant type.
10. Check and water regularly.

25. Growing plants Collect a copy of the booklet.
Follow the instructions under the growing plants title to complete practical 1.

26. Maintaining plants

27. Maintaining plants Learning intention:
Describe different methods of maintaining plants.
Why?
Plants are an important resource, it is important to understand how to grow them.

28. Maintaining plants
As well as growing plants, it is important to know how to maintain them.
This means keeping the plant healthy and growing well.
Do you know how we can do this?

29. Maintaining plants
It is important to control the conditions a plant is grown in.
This helps them to grow as quickly as possible, today we will look at:
Fertilisers
Controlling pests and diseases
Protected cultivation

30. Fertilisers A fertiliser is a substance which has extra nutrients.
If a plant’s compost or soil is lacking nutrients, fertiliser can be added to enrich it.
Different fertilisers contain different amounts of chemicals.

31. Fertilisers
There needs to be the correct balance of minerals in the soil or compost for the plants to grow well.
The balance of N, P and K in fertilisers vary to meet the needs of different plants.

32. Fertilisers
The proportions of N, P and K in a fertiliser are given in a ratio.
For instance, the fertiliser in the picture is 8% nitrogen, 20% phosphorous and 16% potassium.

33. Fertilisers
Fertilisers can be supplied as liquids or as granules (small pellets).

34. Controlling pests
A pest is an animal which will cause damage to a plant.
One example is the aphid.
The most common type of aphid is the greenfly.
They damage plants by sucking the plant’s sap .

35. Controlling pests
Pests such as aphids can be controlled using pesticides which kill insects, mites and other pests.
We can also use insecticides to kill aphids, these only kill insects.
Insecticide/pesticides may kill the aphid when it comes into contact with the chemical.

36. Controlling pests
Biological control means preventing the pest damaging the plant by introducing a natural enemy.
For example lady birds will eats aphids.
This works well in enclosed areas such as greenhouses.

37. Controlling diseases
A disease is a condition caused by a micro-organism which damages a plant.
An example of a fungal disease is grey mould.
Leaves are vulnerable to this disease which causes fuzzy fungal growth on the affected areas.

38. Controlling diseases
To control diseases such as grey mould, plants can be sprayed with a fungicide.
Fungicide is a type of chemical which kills fungi such as grey mould.

39. Protected cultivation
Freshly sown seeds and young seedlings are all open to damage.
Damage can be caused by adverse weather conditions.
For example rain, wind and in particular frost.

40. Protected cultivation
We can prevent plants being damaged by protecting them.
This is called protected cultivation.
Protected cultivation allows farmers to sow seeds earlier in the year, because the seedlings are protected from harsh winter conditions.

41. Protected cultivation
One way of protecting outdoor plants is using glass.
For example greenhouses and cold frames.
The glass retains heat and protects the plants from cold, wind etc.

42. Protected cultivation
Plastic can also be used to protect outdoor plants.
It is lightweight, cheap and retains heat.
It protects the plants from cold, wind etc.

44. Protected cultivation
Poly tunnels are good for covering large areas cheaply.
They are made from plastic sheeting stretched over wire hoops.

45. Protected cultivation
A floating fleece is a type of man-made material which can be place over crops.
The fleece helps keep the soil warm and gives protection from frost and insects.

47. Maintaining plants Collect a copy of the booklet.
Complete the what to do section under the maintaining plants title.

48. Maintaining plants
Once plants are established (growing) there are certain techniques we can carry out to keep them growing as quickly as possible.
These methods include, pricking out, potting on and dead heading.
Do you know what any of these are?

49. Pricking out
When seeds are planted in a tray they grow very close together.
They need to be separated or they will start to compete for light, space and minerals.
If we do not prick the seedlings out, they may die.

50. Pricking out Fill a pot with compost and level off.
Use a pencil to make holes in the compost about 2 cm deep.

51. Pricking out Dig up a seedling using a spatula.
Lower it into one of the holes in the new pot.
Fill in compost around the seedling

52. Potting on
When plants outgrow their pot, they are said to be pot-bound.
Pot-bound plants:
have roots poking out of the bottom of the pot.
their compost dries out very quickly.
growth rate is slowed.

53. The plant cannot grow well when it is pot bound because the roots have no space to absorb water.

54. Potting on Pot-bound plants have to be potted on into a larger pot.
Potting on or re-potting is the transfer of a plant from one pot to another larger one.
This gives the plant’s roots more space to grow so the plant itself can continue to grow.

56. Potting on
Your teacher will demonstrate the potting on process.

57. Dead heading
Usually plants produce a set of flowers which die when they have made their seeds.
This means the plants not longer produces any flowers.
If the dead flower heads are removed regularly, the plant may produce more flowers.

58. Dead heading Dead heading is removing dead flowers from a plant.
Dead heading encourages flower growth because the plant directs its energy to flower buds instead of fruit production.

59. Maintaining plants Collect a copy of the booklet.
Follow the instructions for practical 2 under the maintaining plants title.
When you are finished, turn the page and complete the maintaining plants continued section.

60. Commercial uses of plants

61. Commercial uses of plants
Learning intention:
Describe some commercial uses of plants.
Why?
Plants are a valuable resource with many uses.

62. Commercial uses of plants
Plants are a very important resource.
Collect a mini whiteboard and write down as many uses of plants as you can think of.

63. Food source Plants are the original source of food in a food web.
Humans eat a variety of different plants, we also eat animals which rely on plants for their food source!

64. Raw material
Raw materials are used make products or structures.

65. Medicine We use a variety of plants to produce different medicines:
Morphine – opium poppy
Heart stimulant (digitalis) - foxglove

66. Ornamental
Plants can be very pleasing to look at, they are used in a variety of different areas to improve the way they look i.e. gardens, towns etc.

67. Commercial uses of plants
Collect a copy of the booklet.
Complete the what to do section under the commercial uses of plants section.

68. Pharming Pharming is a combination of two words:
Pharmaceuticals which means medicines.
Farming which is the production of a useful product.
Pharming involves using plants to make medicines.

69. Pharming You are going to carry out some research into pharming.
You will use the laptops to answer the questions on the next slide.
Answer in FULL SENTENCES.

70. Pharming questions What is plant pharming?
What types of plants can be used in pharming?
Name some useful substances which can be made by plants.
These plants are described as “transgenic”, what does transgenic mean?
What are the advantages of pharming?
Are there any disadvantages to pharming?

71. www. gmo-compass. org/eng/agri_biotechnology/breeding_aims/150