Chapter Notes - Reproduction in Plants Class 7 Notes | EduRev

Science Class 7

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Class 7 : Chapter Notes - Reproduction in Plants Class 7 Notes | EduRev

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Reproduction in Plants - Chapter Notes

Sexual Reproduction in Plants

The process of producing young ones that look like the parents is called reproduction.

The process of producing young ones that look like the parents is called reproduction. Plants reproduce either sexually or asexually. Plants reproduce sexually by the most attractive part, called the flower.

Chapter Notes - Reproduction in Plants Class 7 Notes | EduRev

The stalk of a flower is called the pedicel.
All floral parts are arranged on its flattened tip, called the receptacle.
The stamens and the pistil are the reproductive parts of a flower.
The anther contains pollen sacs that produce pollen grains.
Pollens are the male reproductive unit of the flower.
Pistil is the female reproductive part of the flower.
Bisexual flowers contain both - the stamens and the pistil. For example, mustard and rose.
Unisexual flowers have either the stamens or the pistil. For example, cucumber, maize and watermelon.

The transfer of pollen grains from one flower to another is called pollination. Pollen grains transfer from one flower to another by pollinating agents

The transfer of pollen grains from the anther of one flower, to the stigma of another flower on another plant of the same type, is known as cross-pollination. The transfer of pollen grains from the anther to the stigma of the same flower or to the stigma of another flower on the same plant, it is termed self-pollination. The zygote is formed by the fusion of the male and female gametes.

Chapter Notes - Reproduction in Plants Class 7 Notes | EduRev

This process is called fertilisation. After fertilisation, the ovary changes into a fruit. It may be either fleshy or dry. Seeds and fruits are dispersed by agents like wind, water, animals and humans. The pods present in these seeds dry up in the sun. This causes the pod to split with great force, thereby dispersing the seeds away from the parent plant. Some seeds are dispersed by a special method called explosion. Examples are mustard, ladies finger, peas, bean, pod and castor.

The process by which all living things produce young ones that look like themselves is called reproduction. Plants reproduce either sexually or asexually.

Flowers are the most attractive and the reproductive parts of a plant. A flower may have a stalk-like structure, called the pedicel. The sepals, petals, stamens and the pistil are arranged on its flattened tip, called the receptacle.

The stamens are the male reproductive parts.

The pistil is the female reproductive part.

The pistil produces gametes. Gametes are the reproductive cells.

The anther is a knob-like structure of the stamen.

The filament is the long part of the stamen.

The anther contains pollen sacs, which produce pollen grains. Pollen grains are yellow powdery particles containing the male gametes or the male reproductive cells.

The number of stamens in a flower are three or five, or in multiples of three of five.

The ovary contains numerous ovules.

Each ovule contains a female gamete or egg cell.

The basal swollen part of the pistil is the ovary.
The pistil is the centrally located female reproductive part of a flower.

The stigma and the style are major parts of the pistil.

A flower with a stamen and a pistil is a bisexual flower.

A flower that has either a stamen or a pistil is a unisexual flower.

Pollen grains from the stamen fall on the stigma for reproduction to take place.

The transfer of pollen from the stamen to the stigma is known as pollination.

The transfer of pollen from the stamen to the stigma of the same flower is called self-pollination.

The transfer of pollen from the stamen of one flower to the stigma of another is called cross-pollination.

A zygote is formed by the fusion of a male gamete and a female gamete.

After fertilisation, the zygote develops into an embryo.

The ovule develops into a seed.

The seeds of the coconut tree fall into water when they ripen.

The pond iris is adapted for seed dispersal through water.

Seed dispersal is a method of dispersal of seeds through water, animals, birds, wind or insects.
Bursting is also a method to disperse seeds, found in balsam.
Xanthium fruits have spines to get attached to the fur of animals or clothes.
Drumstick seeds are dispersed by the explosion of fruits.
Asexual Reproduction in Plants

Reproduction is mainly of two types - sexual and asexual.
Reproduction is mainly of two types - sexual and asexual. In sexual reproduction, the male and the female gametes fuse to form seeds that eventually develop into new plants. The seeds are formed inside the fruit. On the other hand, in asexual reproduction, a new plant is grown from any part of a plant other than the seeds. There are different methods by which plants reproduce asexually. They are vegetative propagation, budding, fragmentation and spore formation. The vegetative parts of a plant are the roots, stems and leaves. When new plants are produced from these parts, the process is called vegetative propagation.

  • A new rose plant can be grown by cutting off a part of the stem of an existing plant, with two or more nodes, and planting it in the ground.
  • A node is a part of the stem from where a leaf grows.
  • This stem grows into a new rose plant.

These are the buds of a bryophyllum plant. This plant has buds on the edges of its leaves. When the buds come in contact with moist soil, each bud is capable of growing into a new plant. Plants that use buds for vegetative propagation are potato, ginger and turmeric, amongst others. Roots that store food are known as tubers. Such roots are the food storage tanks for the plants.

When these tubers are detached from the parent plant and planted in the soil, they grow into a new plant.
A plant that grows from a single root tuber, and then branches and rebranches, thereby covering a large area.
A number of root tubers are produced by a single plant.
Another plant that is grown from the tuber is the dahlia plant.

Chapter Notes - Reproduction in Plants Class 7 Notes | EduRev
An ingredient used to bake a cake is a single celled plant known as yeast. Yeast reproduces by a process called budding. The small bulb-like projection coming out from the yeast is known as a bud. It detaches from the parent plant and develops into a new plant. Algae, the simplest green plants, reproduce by an asexual method known as fragmentation. An alga breaks up into smaller fragments. Each of these smaller fragments grows into a new independent alga. The white mass and cottony like structure on the bread is called mould.
It is a type of fungus that grows on moist organic surfaces like leather shoes and moist walls. This fungus reproduces by the means of spores.
They can survive in extreme conditions like high temperature and low humidity.
Ferns and moss are the example of the spore type of asexual reproduction.
Placing seeds on or in the ground for future growth is called sowing.
There are several ways by which plants produce offspring (young ones). These are mainly divided into two types - sexual and asexual. The sexual mode of reproduction involves the fusion of the male and the female gametes to form seeds that eventually develop into new plants. In the asexual mode of reproduction, a new plant is grown from a part of the plant other than the seeds.
There are different methods by which plants reproduce asexually. These are vegetative propagation, budding, fragmentation and spore formation.
Roots, stems and leaves are called the vegetative parts of a plant. When new plants are produced from these vegetative parts, the process is called vegetative propagation.
o Bryophyllum propagates vegetatively by the formation of leaf buds on the margins of a leaf. When the buds come in contact with moist soil, each bud is capable of growing into a new plant.
Sweet potato and dhalia are capable of producing young ones from their roots.
Yeast reproduces by a process called budding. A small bulb-like projection that comes out from the yeast is known as a bud. This bud grows and detaches itself from the parent cell, and then grows independently as a new plant.
Yeast is used to bake a cake and to make dough. During budding, yeast respires and releases carbon dioxide. The carbon dioxide released helps the dough to puff up and become spongy.
Algae are green, thread-like plants and grow in stagnant water, ponds and lakes. They float on the surface of the water.
Algae reproduce by a method known as fragmentation. The breaking down of filaments into fragments that grow into young ones is called fragmentation.
Ferns reproduce by releasing spores that germinate into young ones.
The cotton-like white mass on bread formed by fungus is called a mould. It is a type of fungus that grows on moist organic surfaces like leather shoes, moist walls, etc.
Fungus reproduces by means of spores. Spores are covered by a protective hard coat.
Spores can survive in extreme conditions like high temperature and low humidity because of the protective hard coat.
Moss also reproduces by spores.

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