Reproduction in Plants - Asexual Reproduction | CTET Notes based on NCERT

The production of new individuals from their parents is known as reproduction. But, how do plants reproduce?

There are different modes of reproduction in plants. The flowers perform the function of reproduction in plants. Flowers are the reproductive parts of a plant. A flower may have either the male part or the female part or both male and female parts.

There are several ways by which plants produce their offspring. These are categorized into mainly two types: (i) asexual, and (ii) sexual reproduction.

In asexual reproduction plants can give rise to new plants without seeds, whereas in sexual reproduction, new plants are obtained from seeds.

Asexual Reproduction:

In asexual reproduction, new plants are obtained without production of seeds or spores.

Vegetative propagation

It is a type of asexual reproduction in which new plants are produced from roots, stems, leaves and buds. Since reproduction is through the vegetative parts of the plant, it is known as vegetative propagation.

Stem Cutting Of Rose

A node is a part of the stem/branch at which a leaf arises.

Apart from flower 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 consists of a short stem around which immature overlapping leaves are folded. The vegetative buds can also give rise to new plants.

Bryophyllum (sprout leaf plant) has buds in the margins of leaves. If a leaf of this plant falls on a moist soil, each bud can give rise to a new plant.

The roots of some plants can also give rise to new plants. Sweet potato and dahlia are examples. 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.

Plants produced by vegetative propagation take less time to grow and bear flowers and fruits earlier than those produced from seeds. The new plants are exact copies of the parent plant, as they are produced from a single parent.

Plants produced by sexual reproduction have characters of both the parents. Plants produce seeds as a result of sexual reproduction.

Budding

Tiny organism like yeast can be seen only under a microscope. These grow and  multiply every few hours if sufficient nutrients are made available to them. Remember that yeast is a single-celled organism. Let us see how they reproduce?

1. The small bulb-like projection coming out from the yeast cell is called a bud. 
2. The bud gradually grows and gets detached from the parent cell and forms a new yeast cell. 
3. The new yeast cell grows, matures and produces more yeast cells. Sometimes, another bud arises from the bud forming a chain of buds.
4.  If this process continues, a large number of yeast cells are produced in a short time.

Fragmentation

We might have seen slimy green patches in ponds, or in other stagnant water bodies. These are the algae. 

When water and nutrients are available algae grow and multiply rapidly by fragmentation. An alga breaks up into two or more fragments. These fragments or pieces grow into new individuals. This process continues and they cover a large area in a short period of time. 

Fragmentation in spirogyra (an alga)

Spore Formation

Reproduction through spore formation in fungus

We have already learnt that fungi on a bread piece grows from spores which are present in the air. 

When spores are released they keep floating in the air. As they are very light they can cover long distances. 

The spores are asexual reproductive bodies. Each spore is covered by a hard protective coat to withstand unfavorable conditions such as high temperature and low humidity. So they can survive for a long time. 

Under favorable conditions, a spore germinates and develops into a new individual. Plants such as moss and ferns also reproduce by means of spores.

Reproduction in Plants - Sexual Reproduction | CTET Notes based on NCERT