reproduction in plants: a short description

Reproduction – The production of new individuals from their parents is known as reproduction.There are two modes of reproduction in plants as :-1.Asexual reproduction2.Sexual reproduction

Asexual Reproduction – The type of reproduction in which new plants arise without the formation of seeds.It is of following types :-1.Vegetative Propagation2.Budding3.Fragmentation4.Spore Formation

A. Vegetative Propagation :-The type of reproduction in which new plants arise from vegetative parts of the plant is called vegetative propagation.

o In this type of reproduction, new plants arisefrom pre – existing parts of the plant.

o The examples can be as :-•Stem in rose, sugarcane, potato & ginger.•Leaves in bryophyllum.•Roots in sweet potato and dahlia.

Bryophyllum Rose

Potato Ginger

B. Budding :- The reproduction which occurs through the formation of buds is called budding.

o Bud – The small bulb like projection coming outfrom cell is called budding.

o The bud gradually grows and gets detached from the parent cell and forms new cell.

o The process of budding can be seen in yeast.

Budding in Yeast

C. Fragmentation :- The type of reproduction in which a cell breaks up into two or more fragments.

o These fragments grow into new individuals.

o The mode of budding can be seen in algae.

Fragmentation in Spirogyra

D. Spore Formation :- The reproduction through the formation of spores is called spore formation.

o The spores are asexual reproductive bodies.o Under favourable conditions, a spore germinates

and developso into a new individual.o Reproduction through spore formation takes

place in mosses and ferns

Spore Formation in Fern

Sexual Reproduction – The type of reproduction in which new plants arise with the formation of seeds.In this type of reproduction, the reproductive parts of a plants i.e. flowers are involved.Flower consists of two parts as :-A.AttractiveB.Reproductive

Attractive Parts – Those parts which attract insects towards them and which protect the flower are called attractive parts. •There are two attractive parts namely :-1.Petals2.Sepals

Petals – The soft, bright and colourful parts of a flower are called petals.They attract insects towards them for pollination.

Sepals – The harder green parts of a flower below the petals are sepals.They protect the flower from the external dangers.

Petal

Sepal

Reproductive Parts – Those parts of the flower which help in reproduction are called the reproductive parts of a flower.There are two reproductive parts namely :-1)Stamen (Male part)2)Pistil (Female part)

Stamen – The male reproductive part of a flower is called the stamen.A stamen consists of two parts. They are :-I.AntherII.Filament

Stamen

Anther – A small stage like part of the stamen is called anther.It holds the pollen grains on it.

Anther

Filament – A stick like structure below the anther is called filament.

It holds the anther above it.

Filament

Pistil – The female reproductive part of a flower is called pistil.A pistil consists of three parts. They are –

a)Stigmab)Stylec)Ovary

Pistil

Stigma – A small stage like part of pistil is called stigma.It holds the pollen grain which falls on it during pollination.

Stigma

Style – A tube like part connecting the stigma and ovary is style.Pollen tube grows in it during fertilisation.

Style

Ovary – A small ball like structure under the style is called ovary.It consists of ovules.

Ovary

On the basis of presence of reproductive parts, flowers are of two types. They are :-

Unisexual – Consist either stamen or pistil but not both. E.g. Corn, papaya & cucumber.

Bisexual – Consist both stamen and pistil. E.g. Mustard, rose & petunia.

Unisexual Papaya Flower Bisexual Mustard Flower

These are the parts of reproductive parts of a flower.They are of two types :-

i.Male Gametes – These are produced by pollen grains and are found on the anther.ii.Female gametes – These are found in the ovule of the plant. It is also called egg.

In fertilisation the male and female gametes fuse to form the zygote.

The process of transfer of pollen grains from stamen of a flower to pistil of the same or different flower is called pollination.It is of two types as :-

a.Self Pollinationb.Cross Pollination

Self PollinationThe transfer of pollen grain from the anther of a flower to

the pistil of the same flower is called self pollination.In this case, mostly the pollination occurs easily without any

external agency.It takes place only in bisexual flowers.

Cross PollinationThe transfer of pollen grains from the anther of a flower to

the pistil of another flower is called cross pollination.In this case, an external agency such as insects is a must.It can take place in unisexual as well as bisexual flowers.

i. The process of fusion of male and female gametes is called fertilisation.

ii.After fertilisation, a new cell is formed.iii.The cell which results after fusion of the

gametes is called zygote.iv.The zygote further develops to form an

embryo.

Fertilisation (Zygote Formation)

1. Fruit – The ovary, after fertilisation, grows into a fruit.The ripened fruit is ovary.

2. Seed - The ovules, after fertilisation, grows into seed.The seed contains an embryo inside a tough seed coat.

1. A same kind of plant grows in different places. It is due to the process of seed dispersal.

2. The process of carrying of seeds from one place to another is called seed dispersal.

3. Their are many modes of seed dispersal either by wind, by water, by some animals or by blasting.

Through AirSome seeds have wing like structures or are extremely light and hence flow away with wind.Examples of such seeds are Drumstick, Maple

Some seeds have hairy structure which helps in their movement like sunflower.

Seeds of DrumstickSeeds of Maple

Fruit of Sunflower

Through Water1. Some seeds are dispersed through water.2. These fruits or seeds usually develop floating

ability in form of spongy or fibrous outer coat.3. The example of such a way of dispersal is of

coconut.

Seed of Coconut

By Animals1. Some seeds are dispersed by animals.2. These are spiny seeds with hooks.3. They get attached to the body of animals and are carried to distant

places.4. Examples are of seeds of Xanthium and Urena (Caesar’s Weed).

Seed of Xanthium Seed of Urena (Caesar’s Weed)

By Blasting1. Some seeds are dispersed when the fruit bursts with

sudden jerks.2. These seeds are scattered far from the parent plant.3. Examples are of seeds of Castor and Balsam.

Balsam seed and its covering