REPRODUCTION
The ability of the living organisms to
produce new living beings similar to
themselves is called Reproduction.
FISSION
Fission means ‘to break’. Thus in this method an organism can divide
into two or more organisms. So it can be of two types:
1. Binary fission
2. Multiple fission
Binary Fission
The term ‘binary fission’ consists of two words ‘binary’ and ‘fission’.
The word ‘binary’ means ‘two’ and the term ‘fission’ means ‘to
break’. It may be defined as the division of an organism into two
offspring's or daughter organisms.
This method of reproduction is found in algae, fungi and bacteria. In
this method under favorable conditions the parent organisms grows to
its full extent and then divides into two parts. Each part of the parent
then separates and grows into a new organism. This process is repeated
further by the new organisms to produce a large number of organisms.
Binary fission
ALGAE
FUNGI
SPORE FORMATION
Spore formation is a method of asexual reproduction which is found
in non flowering plants such as fungi (Rhizopus) and bacteria. In this
method of reproduction, the parent plant produces hundreds of tiny
spores which can grow into new plants. The spores are the
microscopic, tough and resistant bodies which are round in shape
and can grow into a new plant under suitable conditions. We shall
now discuss the formation of new plants by spores by taking the
example of fungi called as bread mould or Rhizopus.
In Rhizopus numerous spores are produced within sacs
called sporangia as shown in the figure. The sporangia are knob like
structures which are present at the top of the thread like structures
called hyphae. When these sporangia bursts, the spores are
scattered by rain, wind or insects and under suitable conditions
develop into a new Rhizopus plant, when they fall on a suitable
substance like bread.
FERNS
MOSSES
FUNGI
LICHENS
FERN
FUNGUS
MUSHROOM
n
HYDRA
BUDDING
YEAST
VEGETATIVE REPRODUCTION
Learning Outcome : 9.1 - Asexual reproduction in plants and animals.
 Some plants have special
underground stems called
rhizomes.
 They resemble roots but
are really stems, indicated
by the presence of scalelike leaves, buds & nodes.
 They grow by branching in
different directions &
forming new plants as they
grow.
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rhizome
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MODIFIED STEM
Vegetative propagation by roots
In some plants vegetative propagation can take
place from roots. For example, in sweet potatoes the
roots bear adventitious buds from which new plants
can develop when it is buried in the moist soil. Such
roots are called reproductive roots.
MODIFIED ROOTS
Learning Outcome : 9.1 - Asexual reproduction in plants and animals.
• Some plants are capable of
producing young plants along their
leaf margin.
• These miniature plants are
called plantlets.
• These little structures grows a
short stem & roots before they
drop to the ground & grow into
independent new plant.
• These plants have meristematic
tissue along the margins of their
leaves capable of producing plantlets
at each notch of the leaf.
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Bryophyllum daigremontianum produces plantlets
along the margins of its leaves. When they are
mature enough, they drop off and root in any
suitable soil beneath.
plantlets
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Vegetative propagation by leaves
Vegetative propagation can also take place from the leaves. This method is found in
plants such as Bryophyllum and Begonia.
Vegetative propagation by leaves in Bryophyllum
In the leaves of Bryophyllum meristamatic marginal notches are present. From
these meristamatic tissues new plants can develop after coming in contact of soil. The
new plants can detach from the leaves and develop into a full plant after falling on the
ground.
Advantages of vegetative propagation
1.The new plants produced by vegetative propagation are exactly like
the parent plant i.e. the new plants possess all characteristics of the
parent plant.
2.The plants produced by vegetative propagation grow rapidly.
3.Desired varieties and qualities of fruits and plants can be produced by
vegetative propagation.
4.Those plants can also be produced by vegetative propagation which do
not produce seeds or which cannot produce viable seeds.
5.The desirable characters of a variety can be preserved indefinitely
through vegetative reproduction.
Grafting to produce desirable traits
TISSUE CULTURE
Sexual Reproduction in Plants
Female Part (GYNOECIUM)
Male Part(ANDROECIUM)
(Pistil)
(Pollen grains)
Male Part(ANDROECIUM)
STAMEN
Female Part (GYNOECIUM)
PISTIL
Dispersal by Wind: Seeds of some plants are light-weight and some hairlike or wing-like structures are present on them. Such seeds float on air
and are thus dispersed by wind. Example: Dandelion, maple, drumstick,
etc.
Dispersal by Water: Dispersal by water takes place in some aquatic
plants and in some which grow near a water body. Seeds of water lily
float and thus dispersed by water. The coconut seed has a tough fibrous
covering which has plenty of air inside. This helps the coconut seeds in
floating on water.
Dispersal by Animals: Some seeds have spine like structures on them.
They get stuck to the fur of animals and thus get spread to different
places. Examples; guava,apple,mango etc. Some seeds are swallowed
by birds and animals along with fruits. These seeds get dispersed with
bird or animal droppings.
Dispersal by Bursting: Some fruits burst open when they mature. The
force of bursting is enough to spread the seeds. Examples; Ladyfinger,
castor, balsam, etc.