Reproduction in Plants Summary Class 7 NCERT Summary Chapter 8

What is reproduction?

It is a process of production of new individuals from their parents is known as reproduction.

Mode of reproduction:

There are two modes of reproduction:

• Sexual reproduction
• Asexual reproduction

Sexual reproduction

• Two parents are involved in this reproduction.
• Fusion of a female and male cells produced gametes.
• Parents and offspring are non-identical
• Variation is present in the same species.

Asexual reproduction

• There is no need for production of seed to obtain new plant.
• Single parents is involved in asexual reproduction.
• There is no gametes produced.
• The parent and offspring are identical.

Different types of Asexual Reproduction

• Vegetative reproduction
• Budding
• Fragmentation
• Spore formation

1. Vegetative reproduction
New plants are produced from vegetative parts of plants like roots, stems, leaves and buds, it is known as vegetative reproduction.

Advantages of vegetative propagation

• Method of propagation for seedless plants.
• Exact copies of parent plant are produced.
• Large numbers of offsprings are produced.
• Disease free plants can be propagated.

2. Budding

• Small bulb-like cellular out growth called bud.
• It is formed on parent cell that develops into an independent organism called yeast.

3. Fragmentation

• Adult organism breaks into two or more pieces and forms a new individuals called fragments.
  Examples: spirogyra, focus

4. Spore formation

• It is an asexual reproductive microscopic single or multi-celled spherical bodies which germinate into new plants during favorable conditions.
  Examples: mosses, ferns

Sexual reproduction in Plants

• A plant reproduces sexually with the help of flowers.
• Stamen and pistil are the reproductive parts of a flower.
• Stamen is the male reproductive part and pistil is the female reproductive part.
  (i) Bisexual flowers: Flowers which contains both pistil and stamens are called bisexual flowers.
  (ii) Unisexual flowers: Flower which contains either pistil of stamens is called unisexual flowers.
• Stamens: It is a male reproductive part.
• Pistil: it is a female reproductive part.

Pollination

• It is a transfer of pollen grains from anther to stigma of a flower is known as pollination.
• Pollination is a first step of seed formation.

Types of pollination

There are two types of pollintaion:

• Self-pollination
• Cross pollination

(i) Self-pollination: In this pollination pollen grains are transferred from anther to stigma of the same flower.
(ii) Cross-pollination: In this pollination pollen grains are transferred from anther of one flower to stigma of another flower.

Fertilization

• It is process of fusion of male gamete and female gamete is called fertilization.
• Fertilization produces zygote.
• Zygote develops into an embryo.

Formation of fruits and seed

• After fertilization process the ovary enlarges to form the fruit.
• Wall of ovary become the fruit wall.
• Ovules become seeds.
• The remaining part of the flower i.e., petals, sepals and other part usually dry up and fall off.
• Embryo enclosed in a protective seed coat.

Seed dispersal

• It is a process by which seeds or fruits are scattered is called dispersal.

Main method of seed dispersal

• Wind dispersal: drumstick, dandelion and maple
• Animal dispersal: Plants having fleshy fruits. Example: apple, strawberries.