Introduction

All living organisms reproduce. What it means in simple terms is that living organisms produce
young ones of their own kind. For example, a cat produces kittens which grow into adult cats. In
plants too, seeds grow into young seedlings. The seedlings in due course of time develop into
mature plants, as in a mango tree.
Reproduction is one of the most important properties of living organisms. It means creating new
life, producing young ones of their own kind.
Why living organisms need to reproduce?
All living organisms have a fixed life span. During their life span, the organisms perform various
life functions including reproduction. In an annual plant, the life span is about one year, and in a
perennial plant, it goes up to many years. Then the organisms die leaving behind individuals of
their own kind. Thus, they ensure by reproducing during their life span. If they would not
reproduce, then after their death, there would be no organisms left. The species would thus
perish. Reproduction is, thus, the means of perpetuation of species.
Modes of reproduction in plants
Flowers produce seeds which are formed by the fusion of a male
gamete with a female gamete. We sow these seeds and grow
more plants of the same type. This is the most common method
of growing new plants. This type of reproduction is called sexual
reproduction.

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Can we grow new plants without seeds? Yes. There are some plants which do grow without
seeds. These plants give rise to new plants from a part of stem, root, leaf or bud. These parts of
the plant are called vegetative parts and hence the process, vegetative propagation. For example,
a new plant of rose is produced by growing a cutting from one of its branches.
This type of reproduction, which takes place without seeds, is called asexual reproduction.
Sexual reproduction is characterized by the fusion of two cells (gametes) usually coming from
two parents. New plants are produced from seeds. On the other hand, asexual reproduction does
not involve the union of gametes. New individual is produced from a single parent.
Methods of Asexual Reproduction
1. Budding: Asexual mode of reproduction in which a small outgrowth (bud) appears on
the body of the organism. Budding is commonly observed in yeast. A bulb-like projection,
called the bud, is formed on the body. The nucleus of the body divides into two. Then, one
of the two nuclei passes into the bud. The bud detaches itself from the parent body. It
grows to full size and becomes a new individual.

Aim
To observe budding in yeast.
Method
Take about 10 grams of yeast powder and put it in a glass beaker containing warm water in
which a spoonful of sugar has been dissolved. Yeast powder can be obtained from a bakery or a
chemist shop. Keep the beaker in a warm place (at about 35° to 40°C). After an hour, take a drop
of solution from the beaker on a glass slide and observe the slide under the microscope. Make a
sketch of what you observe.
Observation
You will observe budding in yeast.
2. Fragmentation: In some filamentous organisms such as algae (slimy green patches in
ponds or in stagnant water bodies), the filaments break up into two or more fragments.

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 Each fragment or piece grows into a new individual. This process continues and cover a
large area in a short period of time.

3. Spore formation: In non-flowering plants (the plants

which do not produce seeds- ferns, mosses), fungi
(dung mould), formation of spores is a common
method of reproduction. Spores are very small in size.
They have thick walls. The thick walls help the spores
to survive in adverse conditions like high
temperature, low humidity scarcity of water and lack
of food. The spores give rise to new organisms under
favourable conditions.

Aim
To grow fungi like bread mould.
Materials required
Take a small piece of bread, a paper napkin, a small jar or bottle with cap and water.
Method
(a) Cut a piece of the napkin to fit in the bottom of the jar.
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(b) Pour small amount of water into the jar just enough to wet the paper napkin completely.
(c) Place a piece of bread on the moist paper napkin.
(d) Cap the jar loosely. This is very important.
(e) Place the jar in a dark place where it is not cold.
(f) Look at it everyday for a week and draw pictures showing how the mould looked during
its growth stages.
Observation
You will observe colourful growth on the bread. This is bread mould (fungi).

One must place the cap loosely to allow entry of air and hence, fungi can respire.
4. Vegetative Propagation:
This is an asexual method of reproduction in plants where vegetative parts namely the
root, stem, leaf or buds give rise to new plants. No reproductive organs take part in this
method of reproduction and therefore, no seeds are produced.
(i) Natural vegetative propagation
(a) Vegetative propagation by roots - In sweet potato, dahlia etc., the swollen roots are
present. New plants arise from these swollen roots buried in the soil.

(b) Vegetative propagation by stems - A number of plants like potato,

ginger and turmeric show vegetative propagation by stems. The
potato which you eat is in fact an underground swollen stem
(tuber) which contains stored food material. If you observe a potato
with a magnifying glass, you will find “scars”. These scars are called
‘eyes’. The ‘eyes’ on the potato tuber sprout (germinate) and give
rise to new plants.

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(c) Vegetative propagation by leaves - In bryophyllum, plantlets develop from the margins
of intact leaves. These plantlets on being detached, develop into independent plants. Buds
present in individual notches along the margin of a bryophyllum leaf are capable of
forming new plants.

(d) Vegetative propagation by buds – Flower buds which

develop into flowers are called floral buds. There are
buds in the axil (point of attachment of the leaf at the
node) of leaves which develop into shoots. These buds
are called vegetative buds. A bud has immature
overlapping leaves around and such vegetative buds
can also give rise to new plants.
Bud in the axil
Note:
Plants such as cacti produce new plants when their parts get detached from the main plant body.
Each detached part can grow into a new plant.
Advantages of vegetative reproduction
(i) It is an easier, rapid and less expensive method of propagation. Plants can be grown in
much less time.
(ii) Seedless plants can be raised.
(iii) Plants produced by this method are identical copies of the parent plant and show no
variations.

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(iv) Plants like banana, sugarcane, sweet potato, rose and jasmine do not produce viable
seeds. Such plants can be easily grown by this method.

1. What happens when a leaf of bryophyllum (sprout leaf plant) falls on a moist soil?
2. Write two examples of plants whose roots can also give rise to new plants.
3. What is bread mould?
(ii) Artificial vegetative propagation
Because of the advantages offered by vegetative propagation, humans have used this
method for artificial multiplication of useful plants. For this reason, such multiplication
methods are called artificial methods of vegetative propagation.
Some of these methods are as follows:
(a) Cutting: Artificial method of vegetative propagation in which short lengths of plant stem
or root with node are used for growing new plants.
• Stem cutting: Stem cuttings when put in the damp soil give rise to roots and shoots and
form new plants. E.g. Rose, money plant and sugarcane.

• Root cuttings: In certain plants like lemon, tamarind, etc. root cuttings when put in the
damp soil give rise to roots and shoots and form new plants.

1. When a leaf of bryophyllum falls on a moist soil, each bud can give rise to a new plant.
2. Sweet potato and dahlia are two examples of plants whose roots can also give rise to new
plants.
3. Bread mould is a type of fungi which reproduce by producing spores.
Sexual Reproduction
In nature, sexual reproduction occurs in plants as well as in animals. It is the most common
method of reproduction.

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As stated earlier, two parents, one male and the other female are required for sexual
reproduction. Two types of reproductive cells called gametes are produced from the
reproductive organs of two parents. Male parent produces the male gamete and the female
parent produces the female gamete. The fusion of the two gametes is called fertilization. The
product of fusion of the two gametes is called zygote. The male gamete in a flowering plant is
formed by the pollen grain whereas in animals, it is the sperm. The female gamete in plants is a
large egg-cell in the ovule, while in animals, it is the ovum. After fertilization, the zygote
undergoes cell division and growth. Ultimately, it forms the new individual.
Embryo: A ball-like structure formed after divisions in the fertilized egg (zygote).

Why do we need sexual reproduction?

Explanation
Sexual reproduction brings about the fusion of gametes from both the parents. The zygote
formed possesses characters of both parents.
This also helps to bring variations among new individuals. You can now understand why
children of the same parents show variations.
Sexual reproduction in plants
A flower has commonly four parts. These parts,
in order, from the outside to inside are sepals,
petals, stamens and pistil. Out of these four
parts; stamens and pistil are the important
parts, as these take part in sexual reproduction.
The stamens are the male reproductive part
while the pistil (or carpel) is the female part.
(i) Sepals: The outermost whorl of the
flower consists of sepals. These are the green, leaf like structures at the base of flower.
Sepals protect flower during its development and support the flower when flower
blooms.
(ii) Petals: The second whorl consists of petals. These are colourful structures that surround
the inner parts of flower. Its function is to attract the pollinators.
(iii) Stamen: The third whorl of flower consists of stamen. It consists of an anther and a
filament. An anther is a swollen structure present on the tip of the filament. The anther
produces a powdery substance called the pollen grains. Pollen grains contain the male sex
cell or male gamete. Pollen grains are light and can be carried by wind, water or insects.

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(iv) Pistil: It is a single elongated structure in the centre of the flower. It consists of a basal
swollen portion called the ovary. The ovary continues into a long style and ends in to
knob-like part, the stigma. The ovary contains one or many ovules. The female sex cell or
gamete (egg) is present inside the ovule.

Bisexual Flower: Flowers which contain both stamen and pistil are called bisexual flower.
Examples - Rose, mustard and petunia.
Unisexual Flower: Flowers which contain either pistil or stamen are called unisexual flowers.
Examples- papaya, corn and cucumber.

1. What are the constituents of a pistil?

2. How do pollen grains prevent themselves from drying up?

1. Stigma, style and ovary are the constituents of a pistil.

2. Pollen grains have a tough protective coat to withstand unfavourable conditions such as
high temperature and low humidity, by which it prevents themselves from drying up.
Pollination in Flowering Plants:
Pollination is the transfer of pollen grains from the ripe anther
to the stigma. The transfer of pollen grains to the stigma can
take place in two ways :
(i) Self pollination: Within the same flower or between
flowers of the same plant.
(ii) Cross pollination: Between flowers of different plants
of the same species.
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Cross pollination often involves various external agencies to carry pollen grains from one flower
to another one. These agencies may be air, water, insects or animals. Most flowers are pollinated
by insects.
When you visit a garden during flowering season, you observe many butterflies, bees and moths.
What are the insects doing? Though these insects visit the flowers for nectar or honey, at the
same time, they help in pollination.
When an insect visits a flower, the pollen grains get deposited on the body of the insect. When
this insect visits another flower, the deposited pollen grains now get dusted on the stigma of the
second flower, thus bringing about the transfer of pollen grains from the anther to the stigma
(pollination).
Pollen grains of all flowers are not carried by insects. In some cases, they are carried by wind
(wind pollination). In case of water plants, pollen grains are
carried by water (water pollination).
Fertilization in flowering plants:
Fertilization is a step between pollination and seed formation.
The fusion of the male gamete with the female gamete is called
fertilization.
During fertilization, the following events take place :
1. The pollen grains germinate on the stigma and pollen
tubes develop. The pollen tubes move downwards into the style. These tubes are the
carriers of male gametes.

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2. One pollen tube finally enters the ovule where female gamete is located. Female gamete
or egg cell is present inside the ovule.
3. Finally the male gamete fuses with the female gamete. This completes the process of
fertilization. The fusion product or the cell formed as a result of fusion of the two gametes
is called zygote. The zygote soon develops into an embryo (baby plant).

Formation of fruit and seed:

What happens to the flower after fertilization?

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If you observe carefully, you may see following changes in a flower :
1. The flower loses its bright colour.
2. The sepals, petals and stamens fall off.
3. The ovary increases in size and becomes the fruit. The fruit thus is the ripened ovary.
4. The ovary wall becomes the fruit wall.
5. Inside the ovary, the ovules develop to form the seeds. The seeds develop from the
ovules. The seed contains an embryo enclosed in a protective seed coat.
Some fruits are fleshy and juicy such as mango, apple and orange. Some fruits are hard
like almonds and walnuts.
Functions of fruits
(i) The fruit wall gives protection to the seeds and therefore, to the embryo.
(ii) The fruit is a store house of food material.
(iii) The fruit helps in the dispersal of seeds.
Dispersal of seeds and fruits:
For a seed to give rise to a new plant, certain favourable
conditions are necessary. A seed must fall on a suitable place
where favourable conditions are present.
Let us study the following seeds or fruits to know about the
mechanism of dispersal.
Collect seeds/fruits of drumstick, maple, calotropis (madar),
sunflower, gokhru (tributus), okra (xanthium), urena and
coconut.
Examine these seeds or fruits. What do you find?
You will find different situations :
(i) In some cases like maple, drumstick, winged seeds are present. Light seeds of grass or
hairy seeds of madar (aak) and hairy fruit of sunflower dispersed by wind.
(ii) In urena and xanthium, the seeds are thorny and stick to our clothes as we pass by them.
These seeds also stick to bodies of animals passing nearby. Thus, animals as well as
human beings help in dispersal.
(iii) Some seeds are dispersed by water. These fruits or seeds usually develop floating ability
in the form of spongy or fibrous coat as in coconut.

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(iv) Some seeds are dispersed when the fruits burst with sudden jerks. The seeds are
scattered far from the parent plant. This happens in the case of castor and balsam.
Thus, seeds and fruits may be dispersed to places away from the parent plant by various
means like wind, animals, or water.
Seed dispersal help the plants to
(i) prevent overcrowding.
(ii) avoid competition for water, minerals and sunlight, and
(iii) spread to new habitats.

What will happen if all seeds of a plant were to fall at the same place and grow there?
Explanation

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If all seeds of a plant were to fall at the same place and grow, there would be severe competition
for sunlight, water, minerals and space. As a result, the seeds would not grow into healthy plants.

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 SOME BASIC TERMS
1. Asexual reproduction: The type of reproduction in which seeds do not form.
2. Embryo: A ball-like structure formed after divisions in the fertilized egg.
3. Fertilization: The fusion of male and female gamete is called fertilization.
4. Hypha: Long filamentous structure of fungus.
5. Pollen grain: Structure carrying male gametes.
6. Pollen tube: Hollow tube-like structure formed from pollen.
7. Pollination: Transfer of pollen grains from ripe anther to stigma.
8. Spore: Reproductive cell capable of developing a new individual.
9. Sporangium: An enclosed capsule containing spores.
10. Zygote: Fertilized egg.

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