Transcript How do plants grow? - You Grow

How do
plants grow?
Image courtesy of seeskylab at FreeDigitalPhotos.net
A strategic health initiative from Project HOPE UK
A plant needs...
Water
Air
Light
Nutrients
Warmth
...to grow and be healthy
A strategic health initiative from Project HOPE UK
Air
Plants can make their own food via
a process called Photosynthesis.
Nutrients
Plants absorb carbon dioxide from
the air and draw water and
minerals (nutrients) up from the
earth by the roots. The green
leaves use the energy from
sunlight to change these into
oxygen (which we need to breathe)
and food.
Water
Light
Warmth
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What happens to plants if they don’t have
these things?
The plant on the right has received less light
while growing. It has grown taller but is more
spindly. It has bigger leaves to help it to
capture more light. The leaves are yellow
because they contain less chlorophyll. It is
chlorophyll which gives plants their green
colour. It is used by plants to make food during
photosynthesis. If plants cannot make enough
food eventually they will become weak and die.
Image from Ruhr-Universitaet-Bochum. "How plants counteract against the shade of
larger neighbours." ScienceDaily. ScienceDaily, 19 December 2010.
<www.sciencedaily.com/releases/2010/12/101217152518.htm>.
These plants show signs of a lack of water.
The leaves and flowers are drooping
because not enough water has reached them.
If this continues, the leaves will turn yellow
and brown and the plant will start to die.
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What happens to plants if they don’t have
these things?
Some plants cannot survive cold temperatures.
Plants contain a lot of water. If it is very cold, ice
can form in the plant causing damage.
Some plants survive the cold weather by going
dormant in the winter. They preserve their energy
by stopping the growing process. Some plants lose
their leaves to save energy and water.
The amount of nutrients a plant receives will
affect the size and health of the plant. Plants
which do not get enough nutrients tend to be
smaller and not as healthy. They would be less
likely to survive harsh conditions.
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Plants
The stem holds the
plant upright and
helps the plant turn
towards to Sun.
It carries water and
nutrients up from
the roots to the
leaves.
Roots help to keep the
plant in the ground so it
does not blow away.
They act like straws,
drawing up water and
nutrients from the soil.
The flowers are needed
for
reproduction.
The
bright
colours
attract
insects which help to
spread pollen
Green leaves absorb
carbon dioxide from
the air and energy
from the Sun. They
convert
these
to
food via a process
called Photosynthesis
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Branches carry water
and
nutrients
throughout the tree.
They provide support
for the leaves.
The trunk supports the
branches and holds the
tree upright. Water and
nutrients are carried up
from the roots to the
branches and leaves.
Roots keep the tree in
the ground and draw
water and nutrients up
from the earth. The
root system can be as
big, or even bigger than
what we see above
ground.
Trees
The flowers on trees
are sometimes called
blossom.
Blossom
often appears in the
spring and is needed
for
reproduction.
When the blossom
falls off, fruit forms
on the tree.
Green leaves create
food for the tree via
a
process
called
Photosynthesis.
Chlorophyll in leaves
uses energy from the
Sun to convert carbon
dioxide
absorbed
from the air and
water drawn up by
the roots into food.
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Plants and Trees
Flowers are needed for reproduction. The
bright colours attract insects which help to
spread pollen. Flowers which grow on tress
are often called blossom. When flowers die
away, fruits and seeds form in their place.
Green leaves create food for plants and
trees via a process called photosynthesis.
Chlorophyll in leaves uses energy from the
Sun to convert carbon dioxide absorbed
from the air and water drawn up by the
roots into food.
The stem of a plant holds the plant upright
and carries water and nutrients up from the
roots to the leaves. The trunk of a tree has
the same function. Branches support the
leaves.
Roots keep plants and trees in the ground
and draw water and nutrients up from the
earth. The root system can be as big, or
even bigger than what we see above ground.
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Types of Trees
There are two main types of trees – Evergreen and Deciduous
Deciduous trees lose all of their leaves when
conditions change. Some trees lose their leaves in the
autumn, ready for winter, or in the dry season in
tropical areas. Deciduous trees lose their leaves to
conserve water and energy, making it more likely the
tree will survive the harsh conditions. New leaves will
grow in the next growing season. Examples of
deciduous trees include oak, elm, beech and willow.
Evergreen trees do lose their leaves, but gradually
throughout the year and not all at once. Evergreens
have developed to be able to conserve water. In cold
countries, evergreen leaves are shaped like needles,
which help the tree to conserve water. Examples of
evergreen trees are the fir and spruce trees we use
as Christmas trees!
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Evergreen or Deciduous?
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Deciduous trees lose all of their leaves at once; evergreen trees lose their
leave gradually through the year and not all at once. Think about the trees
you see around you. Can you tell if they are evergreen or deciduous?
Deciduous
Evergreen
Oak tree
Fir tree
Evergreen
Evergreen
Bamboo
Palm tree
Deciduous
Willow tree
Deciduous
Maple tree
Growing crops in Britain
In Britain, the weather is
variable and changes from
day to day. It is called a
temperate maritime climate.
In general, we have cool
winters and warm summers.
On average, it rains every 3
days in Britain!
We have the perfect climate to grow lots of different fruits and vegetables.
Can you think of some we grow here in Britain?
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Growing crops in South Africa
In South Africa, it is very
hot in the summer and cold
in the winter. It is also
much drier than here in
Britain. During the winter
months, they have almost
no rain.
Think about what plants need to grow.
What do you think this means for growing fruits and vegetables in
South Africa?
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