Reproduction In Plants Basic 5 Basic Science Lesson Note

LEARNING OBJECTIVES

By the end of this lesson, pupils should be able to:

1. Define reproduction in plants
2. Identify the two main methods of plant reproduction
3. Explain sexual and asexual reproduction in plants
4. Name the parts of a flower and their functions
5. Describe the process of pollination

LESSON CONTENT

What is Reproduction in Plants?

Reproduction is one of the characteristics of living things that enable them to replicate, reproduce or increase their numbers. It allows plants to create new plants that look like their parents.

Plants need to move from one place to another because they are fixed in one position by their roots. This is why they need the help of external factors like wind, water, insects, and animals for reproduction and to avoid pollination.

Reproduction in plants can occur through sexual or asexual means:

• Sexual reproduction involves the fusion of male and female parts, resulting in the formation of seeds
• Asexual reproduction does not involve the fusion of male and female parts and can occur through methods such as vegetative propagation

Methods of Reproduction in Plants

There are two main methods of reproduction in plants:

1. Sexual Reproduction in Plants

This involves the union of male and female parts in plants to form new plants (seedlings). In sexual reproduction, flowering plants make use of seeds. In most plants, the seedlings are developed from their flowers or fruits. Seeds, which are obtained from flowers, contain both male and female parts. From these seeds, new plants grow.

2. Asexual Reproduction in Plants

This type of reproduction in plants involves the production of young seedlings or new plants from parts of the parent plants. This type of reproduction in plants is also known as vegetative propagation.

In vegetative propagation, the offspring contains the exact genetic copy of the parent because no male-female sex gametes are involved. The types of vegetative propagation include:

• Budding – spore formation
• Fragmentation – vegetative propagation

Types of Asexual Reproduction

There are several methods of asexual reproduction in plants, including:

1. Sexual Reproduction by Seeds

This involves the union of male and female gametes, resulting in the formation of a seed. The male gamete is produced in the pollen, which is carried by the wind or insects to the female reproductive structure, the pistil, where fertilization occurs.

2. Asexual Reproduction

This type of reproduction does not involve the fusion of gametes and can occur through methods such as:

Vegetative Reproduction: New plants can grow from a piece of the parent plant, such as:

• A stem cutting or bulb
• Bulbs – small bulbs that form on the leaf axis of plants such as lilies or onion and can develop into new plants
• Runners: A type of stem that grows horizontally along the ground and gives rise to new plants at its tips
• Rhizomes: Underground stems that can give rise to new plants
• Tubers: Underground storage organs that can give rise to new plants
• Spores: Small reproductive cells that can give rise to new plants

3. Binary Fission

A type of asexual reproduction observed in algae and fungi where the organism splits into two identical parts, each of which develops into a new organism.

4. Fragmentation

A type of asexual reproduction observed in some algae, where the organism breaks into smaller parts, each of which develops into a new organism.

PARTS OF A FLOWER

A flower is the organ responsible for producing fruits in flowering plants. The male and the female reproductive parts of a plant are in the flower.

The Main Parts of a Flower Are:

The Stamen (Male Part): It consists of the anther and filament

The Pistil (Female Part): It consists of the ovary, stigma and style

FUNCTIONS OF EACH PART OF A FLOWER

What is Pollination?

Pollination is one of the ways by which plants reproduce. It involves the transfer of pollen grains from the anther to the stigma of flowering plants.

Types of Pollination

1. Self-Pollination

This involves the transfer of pollen grains from the anther to the stigma of the same flower.

2. Cross Pollination

This involves the transfer of pollen grains from the anther of one flower to the stigma of another flower.

What are the Agents of Pollination?

The agents of pollination are those factors that help in the transfer of pollen grains from the anther to the stigma of flowers. These are the agents of pollination:

1. Wind

Pollen can be carried by the wind from the anthers of one flower to the stigma of another. This type of pollination is called anemophily.

2. Water

Pollen can also be carried by water, which can transfer pollen from one plant to another. This type of pollination is called hydrophily.

3. Animals

Animals such as insects, birds, bats, and mammals can act as agents of pollination by transferring pollen from one flower to another. This type of pollination is called zoophily.

4. Self-Pollination

Some plants can self-pollinate, meaning that the pollen from the anther of a flower fertilizes the ovules in the same flower or in another flower on the same plant.

5. Insects

Entomophily: These are the organisms that act as agents of pollination and include insects, birds, bats and mammals. These are the most common agents of pollination. They are attracted to the flowers by the nectar, pollen, fragrance, color, and shape. They pick up the pollen on their bodies as they move from one flower to another.

EVALUATION QUESTIONS

1. What is reproduction in plants?
2. Name the two main methods of plant reproduction
3. What is the difference between sexual and asexual reproduction?
4. List four parts of a flower
5. What is the function of the anther?
6. What is pollination?
7. Name two types of pollination
8. List three agents of pollination
9. What is the function of petals in a flower?
10. Give two examples of asexual reproduction in plants

ASSIGNMENT

1. Draw and label the parts of a flower
2. Explain how wind helps in pollination
3. Give three examples of plants that reproduce through vegetative propagation

CONCLUSION

Plant reproduction is very important for the continuation of plant species. Plants can reproduce through sexual reproduction (using seeds) or asexual reproduction (vegetative propagation). Flowers play a crucial role in sexual reproduction, and pollination helps transfer pollen from one flower to another with the help of agents like wind, water, and animals.