4. Roots: It is the part of plant which is in the soil
Functions of roots
Anchor the plants to the soil
Absorb water and minerals
from the soil
Help in holding soil together
5. Types of Roots
Tap root
• Is a straight tapering root which
grows vertically down and gives
out branches on all the sides
• Tap root is the main root and the
smaller, side roots are called
lateral roots
Fibrous root
• Some plants have bunch of
similar roots called fibrous roots.
• They consist of many thin, fibre-
like roots.
• They spread out in the soil and
give firm support to the plant
tap root
lateral root fibrous roots
7. Stem: It is the part of plant which rises vertically up
from the ground
Functions of stem
Holds the plant upright
Carries water and minerals from
the roots to the leaves and other
parts of the plant
Carries prepared food from the
leaves to the other parts of the
plant
Holds the leaves in such a way
that leaves are able to get plenty
of sunlight for preparing food
8. Leaves: It is a thin, broad, flat and green part of a plant which
is attached to the stem.
Parts of Leaf
Lamina: The broad green part of the
leaf is called lamina. It is commonly
called as leaf blade.
Petiole: The thin stalk with which leaf
attached to the stem is called petiole. It
is commonly called as leaf stalk.
Mid-rib: The mid-rib or mid-vein
is in the centre of the lamina.
Vein: Large number of veins spread out
from the mid-rib.
Stomata: These are small openings on
the surface of the leaf
9. Functions of leaves
Make food for the plant
Get rid of excess water from
the plant through
transpiration
Carry out the process of
respiration in plants
10. Photosynthesis
• Factors required:
Carbon dioxide - taken by the leaves
from air
Water - is carried into leaves from the
soil through the stem
Sunlight- provides energy for making
food.
Chlorophyll - present in green leaves,
traps energy from the sunlight
A process by which
plants make their
food in the presence
of sunlight is called
photosynthesis.
12. Activity to show that leaves make food by photosynthesis
Pluck a green leaf from a potted plant which has been kept in sunlight
Put the green leaf in a small beaker and cover it completely by adding
alcohol or spirit.
Place the beaker containing leaf and alcohol in a bigger beaker
containing water
Heat the water in bigger beaker over a burner The hot water will then
heat alcohol in smaller beaker. The hot alcohol removes the green colour
(chlorophyll) from the leaf. Keep heating till all the green colour of leaf
is removed. The leaf becomes almost colourless.
13. 5. Remove the leaf from alcohol and wash it thoroughly with water to remove the
chlorophyll.
6. Place the decolourised leaf in a petri-dish. Pour iodine solution over the leaf
with the help of a dropper. The leaf turns blue-black showing the presence of
starch.
14. ACTIVITY TO SHOW TRANSPIRATION IN PLANTS
The leaves of plants give out water constantly
in the form of water vapour (which goes into
air). This process is called transpiration.
Take a well-watered potted plant having big
leaves.
Enclose a leafy stem (or branch) of the plant
in a clean polythene bag and seal the mouth
of polythene bag properly with cellotape.
Keep this potted plant in the sunshine for 2 to
3 hours
We will see a number of water droplets on
the inner side of the polythene
15. This can be explained as follows:
The leaves of plant give out water
vapour. Since the leaves are enclosed in
polythene bag, the water vapour cannot
escape into air. The water vapour given
out by the covered leaves keeps on
collecting inside the polythene bag.
Some of this water vapour condenses to
form tiny drops of water. It is these
droplets of water which we see sticking
to the inner sides of the polythene bag.
This activity shows that the leaves of a
plant lose water through transpiration.
16. Venation :It is arrangement of veins in the lamina
Reticulate venation : The veins in a leaf
occur in an irregular way forming a net-
like design. The veins spread out from the
mid-vein haphazardly.
Eg. Neem, mango, peas, orange, guava,
rose etc
Parallel venation : The veins in the leaf
run parallel to one another on both the
sides of the mid-rib.
Eg . Wheat, rice, sugarcane, bamboo, lily,
banana etc.
17. If you want the know what kind of roots
a plant has, you need not pull out . You
can easily find out by looking at its
leaves.
Plants having leaves with
reticulate venation have
tap roots
Plants having leaves with
parallel venation have
fibrous roots
