to Know Plants
Q27. Name the different parts of the plant. Mention main
functions of each part.
Parts of plants and their function
Stem – The main function of the stem is to
support the shoot of the plant. It conducts water and minerals to the leaves
and transport food prepared by the leaves to the other part of the plant.
Roots – It provide support to the plant in
the soil. It absorbs water and other nutrients from
the soil and transports these things to the stem.
Leaves – It prepares food for plants by the
process of photosynthesis. It helps in interchange of gases between the
atmosphere and the plant and evaporation of water.
Flowers – The primary purpose of a flower
is reproduction. It produces seed which produce new plants.
Q28. Explain the following terms.
Transpiration is a process through which
excess water comes out of leaves into the atmosphere in the form of vapor.
Photosynthesis is the process through which
green plants prepare their food in the presence of sunlight, water, carbon
dioxide and green pigment called chlorophyll.
Petiole is a stalk by which leaf blade is
attached to the stem.
The broad, green part of the leaf is called
The thick central vein present in the
middle of the leaf is called midrib.
The pattern made by fine lines of veins in
a leaf is called the leaf venation.
Bud is a compact knob-like structure that
grows on a plant which later develops into a leaf, flower, or shoot.
Q29. Define the following part of a flower.
Sepals are green leaf like structures
forming the outermost part of a flower that surround the petals.
Petals are brightly colored parts of a
flower that surround the reproductive organs.
Stamens are the small, delicate stalks
which grow at the flower’s center and produce pollen. It consists of an anther
and a filament.
Filament is a fine thread like structure
that supports the anther of a flower.
Anther is a part of a stamen that contains the pollens
and occurs at the tip of filament.
Pistil is the part of a flower that comprises of
stigma, style and ovary.
Ovary is the lowermost and swollen part of
It is a long and slender stalk like
structure that connects the stigma and the ovary.
The stigma is the head of the pistil and is a sticky
platform which receives pollen.
Q30. Explain an activity to show that plant transpires.
Take a healthy plant. Enclose a leafy branch of the plant in a polythene bag
and tie up its mouth. Tie up another branch without leaf with a polythene bag. Keep
the plant in the sun. After a few hours, we observe tiny droplets of water on
the inner surface of polythene bag with leaves and no water in the polythene
bag which encloses the empty branch. This shows that plant transpire.
Q31. Write an activity to test the presence of starch in a leaf.
Take a leaf in a test tube and pour spirit to completely cover the leaf. Now
place the test tube in a beaker half filled with water. Heat the beaker till
all the green colour from the leaf comes out into the spirit in the test tube.
Take out the leaf carefully and wash it in water. Put it on a plate and pour
some iodine solution over it. We will see that colour changes to blue black.
This shows the presence of starch in a leaf.
Q32. How do we know that the leaf has prepared the starch and
not received it from another part of the plant?
To test this, place a potted plant with green leaves, in a dark room for a day
or two. Now, cover a portion of a leaf of the plant completely with black paper
and leave the plant in the sun for a day. Remove the leaf covered in black
paper and pour some iodine solution over it. Change of color to blue black
shows presence of starch.