Reproduction in Plants Class 7 Science Notes - Chapter 12

Introduction

Reproduction

They are of 2 types :

– Asexual Reproduction

Asexual Reproduction

To know more about Asexual Reproduction, visit here.

– Sexual Reproduction

Asexual Reproduction

To know more about Sexual Reproduction, visit here.

Production of new individuals from their parents is known as reproduction.

To know more about Reproduction, visit here.

The modes of reproduction in plants are:

Asexual Reproduction in Organisms

  • In asexual reproduction, organisms can give rise to new organisms without fusion of gametes.
  • Only one parent is involved.

Fission

  • It is a type of asexual reproduction that takes place in unicellular organisms like amoeba, paramecium etc.
  • A single parent cell divides into two or more daughter cells.
  • There are two types:
  1. Binary Fission: a single parent cell divides into two daughter cells. (e.g. amoeba, paramecium)
  2. Multiple Fission: a single parent cell divides into many daughter cells. (e.g. Plasmodium)

Fragmentation

  • Fragmentation is a form of asexual reproduction or cloning, in which an organism is split into fragments.
  • Each of these fragments develop into a mature fully grown individual that are clones of the original organism.
  • Eg: sponges and lichens reproduce through fragmentation.

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Budding

  • Budding is a form of asexual reproduction in which a new organism develops from an outgrowth or bud due to cell division at one particular site of the parent organism.
  • They eventually break away from the parent. Eg: hydra, yeast

udding in Hydra

For More Information On Reproduction Through Budding, Watch The Below Video:

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Spore Formation

  • The term is also used to refer to the process of reproduction via spores.
  • spores are the reproductive bodies and are microscopic.
  • When these spores are released into the surrounding area, they develop into new plants under favourable conditions.
  • E.g. Fungi, Ferns

Vegetative Propagation

  • It is a type of asexual reproduction in which new plants are produced from roots, stems, leaves and buds. Eg: rose, Bryophyllum

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Reproduction in Plants

Sexual Reproduction in Plants

  • Sexual reproduction in plants occurs through the fusion of gametes, which eventually gives rise to seeds that develop into the new plant.
  • Flowers are the parts of the plant involved in sexual reproduction.
  • The male gamete i.e. pollen grains are produced by anthers while the female gamete i.e. ovule is produced by pistils.
  • The male and female gametes meet due to pollination, fuse by fertilization and give rise to a new plant by fruit and seed formation.

For More Information On Plant Reproduction, Watch The Below Video:

To know more about Sexual Reproduction in Plants, visit here.

Pollination

  • Pollination is the act of transferring pollen grains from the male part of the flower i.e. anthers to the female part of the flower i.e. stigma.

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Types of Pollination

There are two types of pollination:

  1. If the pollen happens to land on the stigma of the same flower it is called self-pollination.
  2. When the pollen of a flower lands on the stigma of another flower of the same plant, or that of a different plant of the same kind, it is called cross-pollination.

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Zygote

  • In sexual reproduction a male and a female gamete fuse to form a zygote.
  • So in case of plants, the male gametes present in the pollen grains fuse with the female gamete i.e. egg.
  • This fusion is called as fertilization and the cell formed out of the fusion is called as a zygote.

To know more about Zygote, visit here.

Fertilisation

Fertilization is the phenomena of fusion of the male gamete with the female gamete cell.

Embryo

  • The zygote further develops to form the embryo.
  • In animals, the embryo grows into an adult.
  • In Plants, the embryo further gives rise to shoot system and root system.

Fruits and Seed Formation

  • In plants, post fertilisation, the ovary develops into a fruit and other parts of the flower fall off.
  • The ripened ovary forms the fruit.
  • The ovules form the seeds.

To know more about Seed Formation, visit here.

Seed Dispersal

  • Seeds and fruits of plants are dispersed away by wind, water and animals.
  • The seeds show different characteristics depending on their dispersing agent.

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Wind

  1. Seeds are winged and light to get carried by the wind. eg: maple and drumstick.
  2. Hairy seeds, eg: aak (Madar) and hairy fruit of sunflower.

Water

  1. These seeds or fruits normally develop the ability of floating in the form of fibrous or spongy outer coat, eg: coconut.

Animals

  • Spiny seeds with hooks that are attached to the animal body and are hence carried to distant places. Eg: Xanthium, Urena

Few of the seeds disperse when the fruits burst out with a sudden jerk, which gets scattered away to a distance far from the parent plant. Eg: Balsam and Castor.

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