The World Of Plants Std Grade

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 plantsand…… 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 rootsStrawberry 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

71. pinks_16x9_bb.ram

72. pecangrafting1.ram

73. Plant growthPlant 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 membraneLarge 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:The three main types of nutrient are:
1.Nitrates – used to make proteins
2.Phosphates – used to provide
phosphorus to help photosynthesis and
respiration
3.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.
1.Mr Smith’s plants were small and had
yellow leaves, which mineral were they
missing?
2.Mr Lewis’s plants were a normal size
but had yellow leaves, which mineral
were they missing?
3.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 Plant cells have three “extra” things than
animal cells: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. PhotosynthesisPhotosynthesis
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:Four factors affect photosynthesis:
1.Light – if there is more light
photosynthesis happens faster
3.Water – if there is not enough water
photosynthesis slows down
5.Temperature – the best temperature is
about 30
0
C – anything above 40
0
C will slow
photosynthesis right down
7.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