NCERT Textbook - Nutrition in Plants Class 7 Notes | EduRev

 Page 1


Nutrition in Plants
1
I
n Class VI you learnt that food is
essential for all living organisms.
You also learnt that carbohydrates,
proteins, fats, vitamins and minerals are
components of food. These components
of food are called nutrients and are
necessary for our body.
All living organisms require food.
Plants can synthesise food for
themselves  but animals including
humans cannot. They get it from plants
or animals that eat plants. Thus,
humans and animals are directly or
indirectly dependent on plants.
1.1 MODE OF NUTRITION IN PLANTS
Plants are the only organisms that can
prepare food for themselves by using
water, carbon dioxide and minerals. The
raw materials are present in their
surroundings.
The nutrients enable living
organisms to build their bodies, to grow,
to repair damaged parts of their bodies
and provide the energy to carry out life
processes. Nutrition is the mode of
taking food by an organism and its
utilisation by the body. The mode of
nutrition in which organisms make food
themselves from simple substances is
called autotrophic (auto = self; trophos
= nourishment) nutrition. Therefore,
plants are called autotrophs. Animals
and most other organisms take in food
prepared by plants. They are called
heterotrophs (heteros = other).
Boojho wants to know
how plants prepare
their own food.
Now we may ask where the food
factories of plants are located: whether
food is made in all parts of a plant or
only in certain parts? How do plants
obtain the raw materials from the
surroundings? How do they transport
them to the food factories of plants?
1.2 PHOTOSYNTHESIS — FOOD
MAKING PROCESS IN PLANTS
Leaves are the food factories of plants.
Therefore, all the raw materials must
reach the leaf. Water and minerals
present in the soil are absorbed by the
roots and transported to the leaves.
Carbon dioxide from air is taken in
Paheli wants to know why
our body cannot make food
from carbon dioxide, water
and minerals like plants do.
2020-21
Page 2


Nutrition in Plants
1
I
n Class VI you learnt that food is
essential for all living organisms.
You also learnt that carbohydrates,
proteins, fats, vitamins and minerals are
components of food. These components
of food are called nutrients and are
necessary for our body.
All living organisms require food.
Plants can synthesise food for
themselves  but animals including
humans cannot. They get it from plants
or animals that eat plants. Thus,
humans and animals are directly or
indirectly dependent on plants.
1.1 MODE OF NUTRITION IN PLANTS
Plants are the only organisms that can
prepare food for themselves by using
water, carbon dioxide and minerals. The
raw materials are present in their
surroundings.
The nutrients enable living
organisms to build their bodies, to grow,
to repair damaged parts of their bodies
and provide the energy to carry out life
processes. Nutrition is the mode of
taking food by an organism and its
utilisation by the body. The mode of
nutrition in which organisms make food
themselves from simple substances is
called autotrophic (auto = self; trophos
= nourishment) nutrition. Therefore,
plants are called autotrophs. Animals
and most other organisms take in food
prepared by plants. They are called
heterotrophs (heteros = other).
Boojho wants to know
how plants prepare
their own food.
Now we may ask where the food
factories of plants are located: whether
food is made in all parts of a plant or
only in certain parts? How do plants
obtain the raw materials from the
surroundings? How do they transport
them to the food factories of plants?
1.2 PHOTOSYNTHESIS — FOOD
MAKING PROCESS IN PLANTS
Leaves are the food factories of plants.
Therefore, all the raw materials must
reach the leaf. Water and minerals
present in the soil are absorbed by the
roots and transported to the leaves.
Carbon dioxide from air is taken in
Paheli wants to know why
our body cannot make food
from carbon dioxide, water
and minerals like plants do.
2020-21
SCIENCE 2
Paheli wants to know what is so
special about the leaves that they
can synthesise food but  other
parts of the plant cannot.
Cells
through the tiny pores present on the
surface of leaves. These pores are
surrounded by ‘guard cells’. Such pores
are called stomata [Fig. 1.2 (c)].
Water and minerals are transported
to the leaves by the vessels which run
like pipes throughout the root, the stem,
the branches and the leaves. They form
a continuous path or passage for the
nutrients to reach the leaf. They are
called vessels. You will learn more about
transport of materials in plants in
Chapter 11.
The leaves have a green pigment
called chlorophyll. It helps leaves to
capture the energy of the sunlight. This
energy is used to synthesise (prepare)
food from carbon dioxide and water.
Since the synthesis of food occurs in the
presence of sunlight, it is called
photosynthesis (Photo: light; synthesis :
to combine). So we find that chlorophyll,
sunlight, carbon dioxide and water are
necessary to carry out the process of
photosynthesis. It is a unique process
on the earth. The solar energy is
captured by the leaves and stored in the
plant in the form of food. Thus, sun is
the ultimate source of energy for all
living organisms.
Can you imagine life on earth in the
absence of photosynthesis!
In the absence of photosynthesis
there would not be any food. The
survival of almost all living organisms
directly or indirectly depends upon the
food made by the plants. Besides,
oxygen which is essential for the survival
You have seen that buildings are made of bricks.
Similarly, the bodies of living organisms are
made of tiny units called cells. Cells can be seen
only under the microscope. Some organisms
are made of only one cell. The cell is enclosed by
a thin outer boundary, called the cell membrane.
Most cells have a distinct, centrally located
spherical structure called the nucleus (Fig. 1.1).
The nucleus is surrounded by a jelly-like
substance called cytoplasm.
Cell membrane
Cytoplasm
Nucleus
Fig. 1.1 Cell
Boojho wants to know how water
and minerals absorbed by roots
reach the leaves.
2020-21
Page 3


Nutrition in Plants
1
I
n Class VI you learnt that food is
essential for all living organisms.
You also learnt that carbohydrates,
proteins, fats, vitamins and minerals are
components of food. These components
of food are called nutrients and are
necessary for our body.
All living organisms require food.
Plants can synthesise food for
themselves  but animals including
humans cannot. They get it from plants
or animals that eat plants. Thus,
humans and animals are directly or
indirectly dependent on plants.
1.1 MODE OF NUTRITION IN PLANTS
Plants are the only organisms that can
prepare food for themselves by using
water, carbon dioxide and minerals. The
raw materials are present in their
surroundings.
The nutrients enable living
organisms to build their bodies, to grow,
to repair damaged parts of their bodies
and provide the energy to carry out life
processes. Nutrition is the mode of
taking food by an organism and its
utilisation by the body. The mode of
nutrition in which organisms make food
themselves from simple substances is
called autotrophic (auto = self; trophos
= nourishment) nutrition. Therefore,
plants are called autotrophs. Animals
and most other organisms take in food
prepared by plants. They are called
heterotrophs (heteros = other).
Boojho wants to know
how plants prepare
their own food.
Now we may ask where the food
factories of plants are located: whether
food is made in all parts of a plant or
only in certain parts? How do plants
obtain the raw materials from the
surroundings? How do they transport
them to the food factories of plants?
1.2 PHOTOSYNTHESIS — FOOD
MAKING PROCESS IN PLANTS
Leaves are the food factories of plants.
Therefore, all the raw materials must
reach the leaf. Water and minerals
present in the soil are absorbed by the
roots and transported to the leaves.
Carbon dioxide from air is taken in
Paheli wants to know why
our body cannot make food
from carbon dioxide, water
and minerals like plants do.
2020-21
SCIENCE 2
Paheli wants to know what is so
special about the leaves that they
can synthesise food but  other
parts of the plant cannot.
Cells
through the tiny pores present on the
surface of leaves. These pores are
surrounded by ‘guard cells’. Such pores
are called stomata [Fig. 1.2 (c)].
Water and minerals are transported
to the leaves by the vessels which run
like pipes throughout the root, the stem,
the branches and the leaves. They form
a continuous path or passage for the
nutrients to reach the leaf. They are
called vessels. You will learn more about
transport of materials in plants in
Chapter 11.
The leaves have a green pigment
called chlorophyll. It helps leaves to
capture the energy of the sunlight. This
energy is used to synthesise (prepare)
food from carbon dioxide and water.
Since the synthesis of food occurs in the
presence of sunlight, it is called
photosynthesis (Photo: light; synthesis :
to combine). So we find that chlorophyll,
sunlight, carbon dioxide and water are
necessary to carry out the process of
photosynthesis. It is a unique process
on the earth. The solar energy is
captured by the leaves and stored in the
plant in the form of food. Thus, sun is
the ultimate source of energy for all
living organisms.
Can you imagine life on earth in the
absence of photosynthesis!
In the absence of photosynthesis
there would not be any food. The
survival of almost all living organisms
directly or indirectly depends upon the
food made by the plants. Besides,
oxygen which is essential for the survival
You have seen that buildings are made of bricks.
Similarly, the bodies of living organisms are
made of tiny units called cells. Cells can be seen
only under the microscope. Some organisms
are made of only one cell. The cell is enclosed by
a thin outer boundary, called the cell membrane.
Most cells have a distinct, centrally located
spherical structure called the nucleus (Fig. 1.1).
The nucleus is surrounded by a jelly-like
substance called cytoplasm.
Cell membrane
Cytoplasm
Nucleus
Fig. 1.1 Cell
Boojho wants to know how water
and minerals absorbed by roots
reach the leaves.
2020-21
NUTRITION IN PLANTS 3
Besides leaves, photosynthesis also takes place in other green parts of the
plant — in green stems and green branches. The desert plants have scale- or
spine-like leaves to reduce loss of water by transpiration. These plants have
green stems which carry out photosynthesis.
of all organisms is produced during
photosynthesis. In the absence of
photosynthesis, life would be impossible
on the earth.
During photosynthesis, chlorophyll
containing cells of leaves (Fig. 1.2), in
the presence of sunlight, use carbon
dioxide and water to synthesise
carbohydrates (Fig. 1.3). The process
can be represented in an equation:
During the process oxygen is
released. The presence of starch in
leaves indicates the occurrence of
photosynthesis. Starch is also a
carbohydrate.
+ ?????? ?
+
sunlight
chlorophyll
Carbon dioxide water 
Carbohydrate oxygen
Boojho has observed some
plants with deep red, violet or
brown leaves. He wants to
know whether these leaves
also carry out photosynthesis.
Activity 1.1
Take two potted plants of the same kind.
Keep one in the dark (or in a black box)
for 72 hours and the other in sunlight.
Fig. 1.2
(a) Leaf
Guard cells
(c) Stoma
Stomatal opening
(b) Section of a leaf
Fig. 1.3   Diagram showing
photosynthesis
Light energy
Carbon
dioxide
Oxygen
Chlorophyll
in leaf
Water and
minerals
Stoma
Guard Cells
Chlorophyll
2020-21
Page 4


Nutrition in Plants
1
I
n Class VI you learnt that food is
essential for all living organisms.
You also learnt that carbohydrates,
proteins, fats, vitamins and minerals are
components of food. These components
of food are called nutrients and are
necessary for our body.
All living organisms require food.
Plants can synthesise food for
themselves  but animals including
humans cannot. They get it from plants
or animals that eat plants. Thus,
humans and animals are directly or
indirectly dependent on plants.
1.1 MODE OF NUTRITION IN PLANTS
Plants are the only organisms that can
prepare food for themselves by using
water, carbon dioxide and minerals. The
raw materials are present in their
surroundings.
The nutrients enable living
organisms to build their bodies, to grow,
to repair damaged parts of their bodies
and provide the energy to carry out life
processes. Nutrition is the mode of
taking food by an organism and its
utilisation by the body. The mode of
nutrition in which organisms make food
themselves from simple substances is
called autotrophic (auto = self; trophos
= nourishment) nutrition. Therefore,
plants are called autotrophs. Animals
and most other organisms take in food
prepared by plants. They are called
heterotrophs (heteros = other).
Boojho wants to know
how plants prepare
their own food.
Now we may ask where the food
factories of plants are located: whether
food is made in all parts of a plant or
only in certain parts? How do plants
obtain the raw materials from the
surroundings? How do they transport
them to the food factories of plants?
1.2 PHOTOSYNTHESIS — FOOD
MAKING PROCESS IN PLANTS
Leaves are the food factories of plants.
Therefore, all the raw materials must
reach the leaf. Water and minerals
present in the soil are absorbed by the
roots and transported to the leaves.
Carbon dioxide from air is taken in
Paheli wants to know why
our body cannot make food
from carbon dioxide, water
and minerals like plants do.
2020-21
SCIENCE 2
Paheli wants to know what is so
special about the leaves that they
can synthesise food but  other
parts of the plant cannot.
Cells
through the tiny pores present on the
surface of leaves. These pores are
surrounded by ‘guard cells’. Such pores
are called stomata [Fig. 1.2 (c)].
Water and minerals are transported
to the leaves by the vessels which run
like pipes throughout the root, the stem,
the branches and the leaves. They form
a continuous path or passage for the
nutrients to reach the leaf. They are
called vessels. You will learn more about
transport of materials in plants in
Chapter 11.
The leaves have a green pigment
called chlorophyll. It helps leaves to
capture the energy of the sunlight. This
energy is used to synthesise (prepare)
food from carbon dioxide and water.
Since the synthesis of food occurs in the
presence of sunlight, it is called
photosynthesis (Photo: light; synthesis :
to combine). So we find that chlorophyll,
sunlight, carbon dioxide and water are
necessary to carry out the process of
photosynthesis. It is a unique process
on the earth. The solar energy is
captured by the leaves and stored in the
plant in the form of food. Thus, sun is
the ultimate source of energy for all
living organisms.
Can you imagine life on earth in the
absence of photosynthesis!
In the absence of photosynthesis
there would not be any food. The
survival of almost all living organisms
directly or indirectly depends upon the
food made by the plants. Besides,
oxygen which is essential for the survival
You have seen that buildings are made of bricks.
Similarly, the bodies of living organisms are
made of tiny units called cells. Cells can be seen
only under the microscope. Some organisms
are made of only one cell. The cell is enclosed by
a thin outer boundary, called the cell membrane.
Most cells have a distinct, centrally located
spherical structure called the nucleus (Fig. 1.1).
The nucleus is surrounded by a jelly-like
substance called cytoplasm.
Cell membrane
Cytoplasm
Nucleus
Fig. 1.1 Cell
Boojho wants to know how water
and minerals absorbed by roots
reach the leaves.
2020-21
NUTRITION IN PLANTS 3
Besides leaves, photosynthesis also takes place in other green parts of the
plant — in green stems and green branches. The desert plants have scale- or
spine-like leaves to reduce loss of water by transpiration. These plants have
green stems which carry out photosynthesis.
of all organisms is produced during
photosynthesis. In the absence of
photosynthesis, life would be impossible
on the earth.
During photosynthesis, chlorophyll
containing cells of leaves (Fig. 1.2), in
the presence of sunlight, use carbon
dioxide and water to synthesise
carbohydrates (Fig. 1.3). The process
can be represented in an equation:
During the process oxygen is
released. The presence of starch in
leaves indicates the occurrence of
photosynthesis. Starch is also a
carbohydrate.
+ ?????? ?
+
sunlight
chlorophyll
Carbon dioxide water 
Carbohydrate oxygen
Boojho has observed some
plants with deep red, violet or
brown leaves. He wants to
know whether these leaves
also carry out photosynthesis.
Activity 1.1
Take two potted plants of the same kind.
Keep one in the dark (or in a black box)
for 72 hours and the other in sunlight.
Fig. 1.2
(a) Leaf
Guard cells
(c) Stoma
Stomatal opening
(b) Section of a leaf
Fig. 1.3   Diagram showing
photosynthesis
Light energy
Carbon
dioxide
Oxygen
Chlorophyll
in leaf
Water and
minerals
Stoma
Guard Cells
Chlorophyll
2020-21
SCIENCE 4
Fig. 1.4  Leaves of various colours
carbohydrates are made of carbon,
hydrogen and oxygen. These are used
to synthesise other components of food
such as proteins and fats. But proteins
are nitrogenous substances which
contain nitrogen. From where do the
plants obtain nitrogen?
Recall that nitrogen is present in
abundance in gaseous form in the air.
However, plants cannot absorb nitrogen
in this form. Soil has certain bacteria that
convert gaseous nitrogen into a usable
form and release it into the soil. These
are absorbed by the plants along with
water. Also, you might have seen farmers
adding fertilisers rich in nitrogen to the
soil. In this way the plants fulfil their
requirements of nitrogen along with the
other constituents. Plants can then
synthesise proteins and vitamins.
1.3 OTHER MODES OF NUTRITION IN
PLANTS
There are some plants which do not have
chlorophyll. They cannot synthesise
food. How do they survive and from
where do they derive nutrition? Like
humans and animals such plants
depend on the food produced by other
plants. They use the heterotrophic
mode of nutrition. Look at Fig. 1.5. Do
you see a yellow wiry branched structure
twining around the stem and branches
of a tree? This is a plant called Cuscuta
(Amarbel). It does not have chlorophyll.
It takes readymade food from the plant
on which it is climbing. The plant on
which it climbs is called the host. Since
it deprives the host of valuable nutrients,
You often see slimy, green patches
in ponds or stagnant water bodies. These
are generally formed by the growth of
organisms called algae. Can you guess
why algae are green in colour? They
contain chlorophyll which gives them
the green colour. Algae can also prepare
their own food by photosynthesis.
Synthesis of plant food other
than carbohydrates
You have just learnt that plants
synthesise carbohydrates through the
process of photosynthesis. The
Perform iodine test with the leaves of
both the plants as you did in Class VI.
Record your results. Now leave the pot
which was earlier kept in the dark, in
the sunlight for 3 – 4 days and perform
the iodine test again on its leaves.
Record your observations in your
notebook.
The leaves other than green also have
chlorophyll. The large amount of red,
brown and other pigments mask the
green colour (Fig. 1.4). Photosynthesis
takes place in these leaves also.
2020-21
Page 5


Nutrition in Plants
1
I
n Class VI you learnt that food is
essential for all living organisms.
You also learnt that carbohydrates,
proteins, fats, vitamins and minerals are
components of food. These components
of food are called nutrients and are
necessary for our body.
All living organisms require food.
Plants can synthesise food for
themselves  but animals including
humans cannot. They get it from plants
or animals that eat plants. Thus,
humans and animals are directly or
indirectly dependent on plants.
1.1 MODE OF NUTRITION IN PLANTS
Plants are the only organisms that can
prepare food for themselves by using
water, carbon dioxide and minerals. The
raw materials are present in their
surroundings.
The nutrients enable living
organisms to build their bodies, to grow,
to repair damaged parts of their bodies
and provide the energy to carry out life
processes. Nutrition is the mode of
taking food by an organism and its
utilisation by the body. The mode of
nutrition in which organisms make food
themselves from simple substances is
called autotrophic (auto = self; trophos
= nourishment) nutrition. Therefore,
plants are called autotrophs. Animals
and most other organisms take in food
prepared by plants. They are called
heterotrophs (heteros = other).
Boojho wants to know
how plants prepare
their own food.
Now we may ask where the food
factories of plants are located: whether
food is made in all parts of a plant or
only in certain parts? How do plants
obtain the raw materials from the
surroundings? How do they transport
them to the food factories of plants?
1.2 PHOTOSYNTHESIS — FOOD
MAKING PROCESS IN PLANTS
Leaves are the food factories of plants.
Therefore, all the raw materials must
reach the leaf. Water and minerals
present in the soil are absorbed by the
roots and transported to the leaves.
Carbon dioxide from air is taken in
Paheli wants to know why
our body cannot make food
from carbon dioxide, water
and minerals like plants do.
2020-21
SCIENCE 2
Paheli wants to know what is so
special about the leaves that they
can synthesise food but  other
parts of the plant cannot.
Cells
through the tiny pores present on the
surface of leaves. These pores are
surrounded by ‘guard cells’. Such pores
are called stomata [Fig. 1.2 (c)].
Water and minerals are transported
to the leaves by the vessels which run
like pipes throughout the root, the stem,
the branches and the leaves. They form
a continuous path or passage for the
nutrients to reach the leaf. They are
called vessels. You will learn more about
transport of materials in plants in
Chapter 11.
The leaves have a green pigment
called chlorophyll. It helps leaves to
capture the energy of the sunlight. This
energy is used to synthesise (prepare)
food from carbon dioxide and water.
Since the synthesis of food occurs in the
presence of sunlight, it is called
photosynthesis (Photo: light; synthesis :
to combine). So we find that chlorophyll,
sunlight, carbon dioxide and water are
necessary to carry out the process of
photosynthesis. It is a unique process
on the earth. The solar energy is
captured by the leaves and stored in the
plant in the form of food. Thus, sun is
the ultimate source of energy for all
living organisms.
Can you imagine life on earth in the
absence of photosynthesis!
In the absence of photosynthesis
there would not be any food. The
survival of almost all living organisms
directly or indirectly depends upon the
food made by the plants. Besides,
oxygen which is essential for the survival
You have seen that buildings are made of bricks.
Similarly, the bodies of living organisms are
made of tiny units called cells. Cells can be seen
only under the microscope. Some organisms
are made of only one cell. The cell is enclosed by
a thin outer boundary, called the cell membrane.
Most cells have a distinct, centrally located
spherical structure called the nucleus (Fig. 1.1).
The nucleus is surrounded by a jelly-like
substance called cytoplasm.
Cell membrane
Cytoplasm
Nucleus
Fig. 1.1 Cell
Boojho wants to know how water
and minerals absorbed by roots
reach the leaves.
2020-21
NUTRITION IN PLANTS 3
Besides leaves, photosynthesis also takes place in other green parts of the
plant — in green stems and green branches. The desert plants have scale- or
spine-like leaves to reduce loss of water by transpiration. These plants have
green stems which carry out photosynthesis.
of all organisms is produced during
photosynthesis. In the absence of
photosynthesis, life would be impossible
on the earth.
During photosynthesis, chlorophyll
containing cells of leaves (Fig. 1.2), in
the presence of sunlight, use carbon
dioxide and water to synthesise
carbohydrates (Fig. 1.3). The process
can be represented in an equation:
During the process oxygen is
released. The presence of starch in
leaves indicates the occurrence of
photosynthesis. Starch is also a
carbohydrate.
+ ?????? ?
+
sunlight
chlorophyll
Carbon dioxide water 
Carbohydrate oxygen
Boojho has observed some
plants with deep red, violet or
brown leaves. He wants to
know whether these leaves
also carry out photosynthesis.
Activity 1.1
Take two potted plants of the same kind.
Keep one in the dark (or in a black box)
for 72 hours and the other in sunlight.
Fig. 1.2
(a) Leaf
Guard cells
(c) Stoma
Stomatal opening
(b) Section of a leaf
Fig. 1.3   Diagram showing
photosynthesis
Light energy
Carbon
dioxide
Oxygen
Chlorophyll
in leaf
Water and
minerals
Stoma
Guard Cells
Chlorophyll
2020-21
SCIENCE 4
Fig. 1.4  Leaves of various colours
carbohydrates are made of carbon,
hydrogen and oxygen. These are used
to synthesise other components of food
such as proteins and fats. But proteins
are nitrogenous substances which
contain nitrogen. From where do the
plants obtain nitrogen?
Recall that nitrogen is present in
abundance in gaseous form in the air.
However, plants cannot absorb nitrogen
in this form. Soil has certain bacteria that
convert gaseous nitrogen into a usable
form and release it into the soil. These
are absorbed by the plants along with
water. Also, you might have seen farmers
adding fertilisers rich in nitrogen to the
soil. In this way the plants fulfil their
requirements of nitrogen along with the
other constituents. Plants can then
synthesise proteins and vitamins.
1.3 OTHER MODES OF NUTRITION IN
PLANTS
There are some plants which do not have
chlorophyll. They cannot synthesise
food. How do they survive and from
where do they derive nutrition? Like
humans and animals such plants
depend on the food produced by other
plants. They use the heterotrophic
mode of nutrition. Look at Fig. 1.5. Do
you see a yellow wiry branched structure
twining around the stem and branches
of a tree? This is a plant called Cuscuta
(Amarbel). It does not have chlorophyll.
It takes readymade food from the plant
on which it is climbing. The plant on
which it climbs is called the host. Since
it deprives the host of valuable nutrients,
You often see slimy, green patches
in ponds or stagnant water bodies. These
are generally formed by the growth of
organisms called algae. Can you guess
why algae are green in colour? They
contain chlorophyll which gives them
the green colour. Algae can also prepare
their own food by photosynthesis.
Synthesis of plant food other
than carbohydrates
You have just learnt that plants
synthesise carbohydrates through the
process of photosynthesis. The
Perform iodine test with the leaves of
both the plants as you did in Class VI.
Record your results. Now leave the pot
which was earlier kept in the dark, in
the sunlight for 3 – 4 days and perform
the iodine test again on its leaves.
Record your observations in your
notebook.
The leaves other than green also have
chlorophyll. The large amount of red,
brown and other pigments mask the
green colour (Fig. 1.4). Photosynthesis
takes place in these leaves also.
2020-21
NUTRITION IN PLANTS 5
Cuscuta is called the parasite. Are we
and other animals also a kind of
parasites? You should think about it
and discuss with your teacher.
hair which are directed downwards.
When an insect lands in the pitcher, the
lid closes and the trapped insect gets
entangled into the hair. The lid closes
and the insect is trapped. The insect is
digested by the digestive juices secreted
in the pitcher and its nutrients are
absorbed. Such insect-eating plants are
called insectivorous plants.
Is it possible that such plants do not
get all the required nutrients from the
soil in which they grow?
Fig. 1.5  Cuscuta (Amarbel) on host plant
Paheli wants to know whether
mosquitoes, bed bugs, lice and
leeches that suck our blood are
also parasites.
Fig. 1.6  Pitcher plant showing lid and pitcher
Leaf modified
into pitcher
Lid
Boojho is confused. If the
pitcher plant is green and
carries out photosynthesis, then
why does it feed on insects?
Have you seen or heard of plants that
can eat animals? There are a few plants
which can trap insects and digest them.
Is it not amazing? Such plants may be
green or of some other colour. Look at
the plant in Fig. 1.6. The pitcher-like or
jug-like structure is the modified part
of leaf. The apex of the leaf forms a lid
which can open and close the mouth of
the pitcher. Inside the pitcher there are
1.4 SAPROTROPHS
You might have seen packets of
mushrooms sold in the vegetable
2020-21