Plants are vital for life on Earth. They convert sunlight into food through photosynthesis, produce oxygen, regulate climate, provide habitats for other organisms, and give us food, materials and medicines. Plants live in almost every habitat and maintain the balance of gases in the atmosphere. They come in a huge variety and have complex structures adapted for reproduction, growth and survival.

1. INTRODUCING PLANTS

2. PLANTS - THE BASICS A huge variety of plants in the world Live in almost every habitat Can survive the harshest environments The link between the sun and all other living things Maintain the balance of atmospheric gases

3. MORE PLANT BASICS They regulate the water content of the soil They provide habitats for other organisms And ……….

4. … . they give us some beautiful artistic moments!

5. VARIETY

6. MORE VARIETY

7. HABITATS

8. MORE HABITATS

9. PLANTS AND THE SUN Plants turn the sun’s energy ……… into food This is called………. Photosynthesis

10. PLANTS ARE ALSO HABITATS

11. WHAT DO WE NEED PLANTS FOR ? For food For raw materials For medicines

12. PLANTS AS FOODS Cereals such as rice,maize,and wheat form the staple foods of most countries Vegetables and fruits add variety to our diets Herbs,spices,sugar,tea,coffee and nuts are all plants and…… we get chocolate from plants !!!!!

13. …. IN SCOTLAND Barley is used to make ….

14. AND…… Plant-based dyes are used for…..

15. PLANTS AS MEDICINES Known about since 2000BC Used for pain relief, reducing fever, sedation and upset stomach, and curing infections Many are used for treating cancer ……And many more medicinal uses

16. PLANTS TREAT CANCER It is thought that at least 2000 plants may contain chemicals which can help to treat cancer This is the purple coneflower

17. PLANTS CLEAR YOUR HEAD This is the titfruit. Its extract can clear blocked sinuses

18. MORE PLANT MEDICINES… Plants can be used for hormone replacement This is squawberry juice being extracted Plants can help with urinary infections This is saw palmetto used for cystitis and Prostate problems in men

19. DO YOU KNOW THIS ONE ?

20. PLANTS AS MATERIALS Cotton for clothes and linens Jute and hemp for rope Trees for timber Rape seeds for oil Seaweeds for alginates How many more can you think of ?

21. PLANTS ARE SO INTERESTING….. These american native indians even worship their cacti….

22. SO…… PLANTS ARE ? Much more complex and varied than you knew

23. “ World of plants” will show you how and why .

24. Ecological loss Tropical rainforests have the greatest variety of plants on earth There loss is disastrous For every type of plant that becomes extinct a wide variety of other dependent organisms are also endangered. For every species of plant that becomes extinct,four species of animal also die out,upsetting the balance of life on earth

25. ENDANGERED SPECIES

27. FOOD PLANTS MOST OF THE WORLDS FOOD COMES FROM A VERY FEW TYPES OF PLANTS AS THE POPULATION INCREASES,THEN SOME OTHER TYPES OF PLANT WHICH ARE NOT WELL KNOWN MIGHT PROVIDE FOOD

28. EVEN FLOWERS !

29. MEDICINAL PLANTS Many important medicines come from plants In the future,possible medicines may never be discovered if the plants are made extinct by destroying the rainforests.

30. WILD PLANTS…… Wild plants also contain many different characteristics … .and different genes which could be useful in the future. … .. So its important to protect the wild varieties for possible future use. THIS IS CALLED A GENETIC STOREHOUSE

31. GENETIC STOREHOUSE Cultivated plants have been bred to be very alike They contain almost exactly the same genes If a new disease infected one,it could easily damage all of them Wild varieties are often resistant to many different diseases It is possible to cross-breed them with cultivated plants to increase the resistance to disease

32. Seed Germination When spring arrives,the seed bursts open and a new plant starts to grow This is called GERMINATION

33. What’s in a seed ? Seeds usually have a hard coat. This is also called the TESTA It’s a tough,fibrous layer which protects the internal structures of the seed Lets have a look at the inside of a seed

34. Inside the seed This Broad bean seed has been left to soak in water overnight. This softens the seed coat and allows us to pull it away from the seed You can now examine the internal structures of the seed

35. Structure of the mature seed In dicot seeds: Hypocotyl terminates in the radicle (embryonic root) Epicotyl terminates in the plumule (shoot tip) Monocot seeds have a special cotyledon called a scutellum : Large surface area - absorbs nutrients from endosperm during germination Embryo enclosed in sheath: Coleoptile protects the shoot Coleorhiza protects the root

36. Inside the Bean seed The inside of a seed is called ….. The EMBRYO It’s made up of two parts… The young shoot(called the PLUMULE ) And the young root ( called the RADICLE) There is also a pair of seed leaves (called COTYLEDONS) they act as a food store

37. The seed germinates First the seed takes up water.This makes it swell The seed coat splits and the new plant starts to grow out,root first Next,the shoot starts to grow. The root grows downwards … .. And the shoot grows upwards The shoot is bent back to protect its delicate tip as it pushes up through the soil

38. …. The embryo starts to grow You can see the root starting To grow downwards

39. Germination continues…. The root tip is protected from damage as it grows down through the soil by a mass of cells called the Root Cap The root grows tiny side branches to help anchor the young plant into the ground These hairs also increase the surface area for absorbtion

40. …. The root grows hairs We can see the root hairs starting to grow

41. Roots – function and structure Hold plant in position Absorb water and minerals from the soil Specialised cells to increase surface area for water intake

42. Wheat seed Root hairs Fragile parts of cells that grow from the main root They massively increase the surface area for absorption

43. Root hair cells (x150)

44. Root ‘B’ has had the hairs damaged -

45. … .and finally The young shoot breaks through the soil surface It straightens out The first leaves open out and turn green Germination is complete and the new plant is called a seedling

46. Factors affecting germination Temperature. Warmth is needed by most seeds.This is why they don’t germinate until the spring Water is needed for the seed to swell and burst open. It is also necessary for the stored food to be made soluble and moved to the growing embryo Oxygen is needed for the embryo to respire.It supplies the embryo with the energy to grow and develop

47. What about light ? Most seeds will germinate in light or dark conditions However some will only germinate in one or the other. The amount of light needed may be very small.One quick flash is enough in some cases All plants need light once the shoot breaks through the surface of the soil. This is to make the leaves open out and form CHLOROPHYLL FOR PHOTOSYNTHESIS

48. CRESS SEEDS GERMINATING

49. REPRODUCTION IN FLOWERING PLANTS

50. Floral diversity THEY ALL LOOK DIFFERENT…BUT ALL HAVE THE SAME PARTS FOR REPRODUCTION…

51. The Parts of a Flower Most flowers have four parts: sepals, petals, stamens, carpels.

52. The parts of a flower Sepals protect the bud until it opens. Petals attract insects. Stamens make pollen. Carpels grow into fruits which contain the seeds.

53. Stamen (male) Anther: pollen grains grow in the anther. When the grains are fully grown, the anther splits open.

54. Carpel(female) Stigma Style ovary Ovules (eggs)

55. Pollination Flowering plants use the wind, insects, bats, birds and mammals to transfer pollen from the male (stamen) part of the flower to the female (stigma) part of the flower.

56. Pollination A flower is pollinated when a pollen grain lands on its stigma. Each carpel grows into a fruit which contains the seeds.

57. Fertilisation Pollen grains germinate on the stigma, growing down the style to reach an ovule. Fertilised ovules develop into seeds. The carpel enlarges to form the flesh of the fruit and to protect the ovary.

58. The ovary develops into a fruit adapted for seed dispersal A true fruit is a ripened ovary Fruits can be classified by their origin: Simple fruits : derived from a single ovary e.g. cherry Aggregate fruits : derived from a single flower with several carpels e.g. blackberry BUT …WHAT ABOUT ‘ FALSE FRUITS’ ?

59. Wind pollination Some flowers, such as grasses, do not have brightly coloured petals and nectar to attract insects. They do have stamens and carpels. These flowers are pollinated by the wind.

60. Seed dispersal Seeds are dispersed in many different ways: Wind Explosion Water Animals Birds Scatter

61. How birds and animals help seed dispersal Some seeds are hidden in the ground as a winter store. Some fruits have hooks on them and cling to fur or clothes.

62. How birds and animals help seed dispersal Birds and animals eat the fruits and excrete the seeds away from the parent plant.

63. ASEXUAL REPRODUCTION Plants can be produced by a single parent No need for sex cells and fertilisation Because of this, there will be NO variation and new plants formed will be…. GENETICALLY IDENTICAL to one another AND to their parent Asexual reproduction in plants is known as VEGETATIVE PROPAGATION.

64. Methods of Artificial propagation… Offspring can be formed from a plant’s stem or buds These are known as RUNNERS The runner carries food from the parent to the new plant whilst it grows leaves and roots Strawberry and Spider plants are good examples of Species which use RUNNERS for asexual reproduction

65. Some plants produce large swollen roots called TUBERS These are food storage organs full of STARCH A plant may produce several of these. Each will produce a new plant which may make many more TUBERS Examples of plants which use this method of VEGETATIVE PROPAGATION include ….

66. Artificial Propagation Some plants lack their own natural methods of artificial propagation These plants can be reproduced by artificial processes. This can be done for several reasons… (1) uniformity is guaranteed (2) Sterile varieties can be reproduced in vast quantities, such as seedless grapes and citrus fruits (3) Rare species can be conserved to protect against extinction TWO METHODS ARE COMMONLY USED… … CUTTINGS AND GRAFTING.

67. …CUTTINGS Stems and leaves are used to grow new plants Roots form from the cutting when it is placed in good soil REMEMBER….ALL CUTTINGS GROW INTO PLANTS WITH FEATURES IDENTICAL TO THEIR PARENT

68. GRAFTING A cutting (SCION)is grafted onto the STOCK of a hardy variety as shown The scion may come from a high yield fruiting plant This method can combine the good qualities of TWO or more plants The cut surfaces bond together, healing the wound which Is protected from infection by being sealed with wax. Twine Holds the cut surfaces tightly together to promote healing

69. Are these plants clones YES…THEY ARE A CLONE is a group of organisms which have exactly the same genetic info and have been produced from a common ancestor by ASEXUAL REPRODUCTION So the term CLONE can be used to refer to a group of Plants produced from cuttings or graftings from the SAME PARENT PLANT

70. There are two film clips coming next They show cutting and grafting taking place in the south of the USA Please be patient…they take a few seconds to load You can only see them if you are watching this presentation on a computer logged on to the internet

73. Plant growth Plants grow using food they make through photosynthesis. So what else do they need? Plants also need three important minerals to keep healthy. They absorb these through their roots.

74. Root hair cells Plant roots are made of “root hair cells” which have a large surface area and a thin cell membrane to help absorb the minerals: Thin cell membrane Large surface area

75. Plant A Plant B Both plants were planted at the same time and left to grow on the same window sill for the same length of time. Why do you think that plant A is so much bigger than plant B?

76. How do plants get the minerals they need? The plant takes in minerals from the soil. It absorbs these minerals through their roots. Remember a plant does not get food from the soil it is capable of making its own food Some plants which grow on poor soil have evolved a clever way to get the nutrients they need. Where do you think they get them from?

78. The three main types of nutrient are: Nitrates – used to make proteins Phosphates – used to provide phosphorus to help photosynthesis and respiration Potassium – helps the enzymes that are needed for photosynthesis and respiration

79. Lack of the three minerals would lead to a “Deficiency Symptom”: Lack of nitrates: Small plant, yellow leaves Lack of phosphates: Small roots and purple leaves Lack of potassium: Yellow leaves with dead bits

80. The Three Main Minerals Needed by Plants. A small plant with yellow older leaves. To make proteins Nitrate Symptom if deficient Why its needed Mineral Yellow leaves with dead bits Helps chemicals in the plant work properly. Potassium Poor root growth and purple younger leaves Needed for photosynthesis and respiration Phosphate

81. Plant Doctor. Mr Smith’s plants were small and had yellow leaves, which mineral were they missing? Mr Lewis’s plants were a normal size but had yellow leaves, which mineral were they missing? Mr Brooke had a plant which had some purple and some yellow leaves, which minerals were they missing?

82. The Transport System There are a set of tube-like tissues that go up and down the leaf stem and shoots that transport the other essential ingredients for photosynthesis : water and minerals There are two tubes called xylem and phloem tissues.

83. The Transport System The xylem brings up the water from the roots The phloem takes away the sugars made by the chloroplasts to places where the energy is needed The tubes are in the middle of the leaf so that there are near all the cells to bring up water and to take away sugars.

85. The transport system The transport system is far less elaborate than in mammals due to: plants are less active and therefore ‘supplies’ don’t run out so quickly because of the branching system, gases for respiration and photosynthesis. Can be obtained from diffusion in the air two separate systems; xylem and phloem

86. Xylem Xylem carries the water and minerals It is made of many hollow dead cells joined end to end of which the end cell wall has disappeared to form a long tube Xylem vessels run from root to every leaf Xylem vessels contain no cytoplasm or nuclei Their walls are made of cellulose and lignin Lignin is very strong and so xylem help keep the plant upright

87. Close up of Hibiscus rosa xylem

88. Phloem Transport the ‘food’ They are also made of many cells joined end to end, however their end wall is not completely broken down; instead they form sieve plates The cells contain cytoplasm but no nucleus and they do have lignin in their walls Each sieve cell has a companion cell next to it which does contain a nucleus and many other organelles

89. Phloem tubes

90. Vascular bundles Xylem and phloem tubes are normally found close together, when they are this is called a vascular bundle In a root vascular tissue is found at the centre In a shoot they are found near the outside edge to help support the plant

91. Transverse section of a stem

92. The transport of water Plants take in water from the soil through the root hairs and is carried in the xylem throughout the plant Water gets into root hair by osmosis. The cytoplasm and cell sap inside it are quite concentrated solutions and the water in soil is normally quite dilute Water therefore diffuses down its concentration gradient through a partially permeable membrane

93. A root tip showing root hairs

94. Transpiration The evaporation of water from the plant Most of which takes place from the leaves through the stomata Guard cells around the stomata control the rate of transpiration by opening and closing

95. Transpiration When water is lost through transpiration water from the xylem vessel in the leaf will travel to the cells to replace it Water is constantly being taken from the top of the xylem vessel to supply the cells in the leaves This reduces the pressure at the top of the xylem so water flows up This process is known as the transpiration stream

96. Leaves

97. THE LEAF! A leaf is an example of a plant organ It is composed of many tissues that work together . The tissues are designed to maximise the levels of photosynthesis.

98. Function of leaves Trap light energy for photosynthesis Producing sugar from photosynthesis Exchange of gases – oxygen and carbon dioxide

99. Structure Wide Helps to catch more light energy Thin Help get carbon dioxide from bottom to top of leaf for photosynthesis

100. Leaf structure Greener on top CO 2 gets in here

101. Leaf diagram – palisade layer CO 2 Most chlorophyll

102. Leaf cell - palisade Position? Upper surface of leaf Features? Box shape Chloroplasts Function? Photosynthesis

103. Plant cells have three “extra” things than animal cells: Both types of cell have these: Only plant cells have these: 4) Cell wall – provides support Large Vacuole – contains sap Chloroplasts – contain chlorophyll 1) 5) 6) 2) 3) Cell Membrane – holds the cell together Cytoplasm - this is where the reactions happen Nucleus – The “brain” of the cell

104. Gas exchange Leaves are designed to allow carbon dioxide to get to the main chlorophyll layer at the top of the leaf They have small holes called stomata on the under surface Each hole is open & closed by 2 guard cells

105. Leaf diagram – stoma and guard cells

106. Stoma position

107. Stoma is a small hole Its size is controlled by 2 guard cells closed open

108. Stoma function is for gas exchange in the leaf Carbon dioxide oxygen Guard cell Provided plant is photosynthesising

109. Stomata open and close at different times of the day When it is light the plant needs CO 2 for photosynthesis so the stoma open At night (darkness) they close

110. Gas exchange

111. Photosynthesis A Photosynthesis is the process a plant uses to make food and grow. The food produced is GLUCOSE. This is a carbohydrate. They are made up of… CARBON, HYDROGEN, and OXYGEN. Glucose is SOLUBLE so the Plant has to convert it into STARCH which is INSOLUBLE Or CELLULOSE for building Cell walls. STARCH is a STORAGE carbohydrate CELLULOSE is a STRUCTURAL carbohydrate

112. Four things are needed for photosynthesis: Travels up from the roots WATER CARBON DIOXIDE Enters the leaf through small holes on the underneath SUNLIGHT Gives the plant energy CHLOROPHYLL The green stuff where the chemical reactions happen

113. The word and chemical equations for photosynthesis: Carbon dioxide + water glucose + oxygen 6CO 2 + 6H 2 0 C 6 H 12 O 6 + 6O 2 Sunlight Chlorophyll Sunlight Chlorophyll

114. Four factors affect photosynthesis: Light – if there is more light photosynthesis happens faster Water – if there is not enough water photosynthesis slows down Temperature – the best temperature is about 30 0 C – anything above 40 0 C will slow photosynthesis right down CO 2 – if there is more carbon dioxide photosynthesis will happen quicker These are known as LIMITING FACTORS because Lack of any one or more will slow down photosynthesis