asexual mode of reproduction by plant | vegetative propagations | fragmentation | budding | spore

Описание: The method of reproduction which involves only a single parent without the formation of
gametes or seeds is called asexual reproduction.
• It occurs in the vegetative parts of a plant.
• Since new plants arise from a single parent, the offspring are identical to the parent and to
each other as well.
• Plants reproduce asexually by fragmentation, budding, spore formation, and vegetative
propagationFragmentation is a common method of asexual reproduction
in filamentous algae like Spirogyra.
• When water and nutrients are present, the alga’s filament
splits into two or more parts, called fragments, and each
fragment develops into a new individual.
In this process, a small bump or outgrowth called a bud forms on the body of the organism.
• The bud grows bigger and eventually separates from the parent body to become a new
individual.
• Sometimes, a new bud starts forming from the first bud before it detaches, creating a chain
of buds.
• Budding is commonly seen in yeast cells
Plants such as ferns and mosses bear asexual bodies called
spores, which are contained in special structures called
sporangia (singular: sporangium).
• These sporangia burst open to release spores.
• Each spore is covered by a hard outer covering which helps it
withstand harsh conditions like high temperature and lack of
moisture.
• Upon restoration of favourable conditions of the atmosphere
and availability of food, each spore germinates into a new
plant.
• Apart from ferns and mosses, a fungus called bread mould
(Rhizopus), also reproduces by spore formation.
• They contain long thread-like structures called hyphae, each
terminating into a bulb-like structure called sporangium,
which bears spores.

Artificial vegetative propagation is a technique where a
part of the plant (stem, root, or leaf) is cut and planted in the
soil to produce new plants. Cutting, layering, grafting, suckering,
and tissue culturing are the methods used for artificial
vegetative propagation.

Vegetative propagation
• Some plants can grow from other parts of the plant besides
seeds.
• The process of growing a plant from other parts of a plant is
known as vegetative propagation.
• The part of the plant from which the new plant grows is
known as the vegetative part.
• Natural vegetative propagation occurs by a plant’s roots,
stems, or leavesVegetative propagation by stem
• Vegetative propagation by stems can be seen from tubers
(potato), bulbs (onion), and rhizomes (ginger).
Tubers
• Underground stems of some plants store food and become
swollen. They contain buds in a depression called eye, such as
in potatoes. If a potato is cut into several pieces, each
containing an eye, each piece will grow into a new plant.
Bulbs
• Underground stems of
some plants are covered by
scaly leaves.
• These leaves store food and
become thick and fleshy.
• They form a structure called
bulb.
• It is found in onions, tulips,
gladiolus, and lilies.
Rhizomes
• Underground stems of
plants like ginger, turmeric,
and banana have scaly
leaves and buds on them.
• The buds develop
outgrowths which can give
rise to new plants.
Vegetative propagation by root
• Plants like carrots, radishes, and
sweet potatoes reproduce from
their roots.
• These plants store food in their
roots.
• A new plant can grow when a
portion of the root containing a
vegetative bud is planted in the
soil.
Vegetative propagation by leaf
• Plants such as Bryophyllum and Begonia reproduce from
their leaves.
• They have buds on the margins of the leaves.
• Small plants grow from these buds.
• When they fall on the ground, they grow into new plants