What is Reproduction in Plants Class 7: Complete Guide for NCERT Students

Definition: What is Reproduction in Plants?

Reproduction in plants is the process through which plants produce new plants or offspring. This process ensures the survival and continuation of plant species. In Class 7 NCERT Science, reproduction is broadly classified into two types:

• Sexual Reproduction: Involves the fusion of male and female gametes.
• Asexual Reproduction: New plants grow from parts of the parent plant without the involvement of gametes.

Both types are important for different plants depending on their species and environment.

Sexual Reproduction in Plants Explained

Sexual reproduction in plants occurs through flowers, which are the reproductive organs. Key steps include:

• Pollination: Transfer of pollen grains from anther (male part) to stigma (female part).
• Fertilisation: Fusion of male and female gametes forming a zygote.
• Seed Formation: The fertilised ovule develops into a seed.
• Fruit Development: The ovary becomes the fruit that protects seeds.

Example: In pea plants, flowers produce seeds after fertilisation, which grow into new plants.

Pollination Types:

• Self-pollination: Pollen from the same flower fertilises the ovule.
• Cross-pollination: Pollen from one flower fertilises another flower.

Asexual Reproduction in Plants: Methods and Examples

Asexual reproduction does not involve seeds or fertilisation. New plants grow from parts of the parent plant. Common methods include:

• Vegetative Propagation: New plants grow from stems, roots, or leaves. Example: Potato tubers, ginger rhizomes.
• Budding: A new plant grows from a bud on the parent. Example: Yeast (fungus).
• Fragmentation: Plant breaks into parts, each grows into a new plant. Example: Spirogyra.
• Spore Formation: Spores grow into new plants. Example: Ferns and mosses.

This method is faster and produces genetically identical plants.

Comparing Sexual and Asexual Reproduction in Plants

Here is a comparison between sexual and asexual reproduction:

Understanding these differences helps Class 7 students grasp how plants adapt and survive.

Pollination and Fertilisation: Key Processes in Plant Reproduction

Pollination and fertilisation are crucial for sexual reproduction:

• Pollination: Pollen grains land on the stigma. This can happen via wind, water, or animals like bees.
• Fertilisation: After pollination, pollen tube grows to ovule, allowing sperm cells to fuse with egg cells.

This results in seed formation. Without pollination and fertilisation, plants cannot produce seeds or fruits.

Worked Example: If a flower has 5 ovules and all get fertilised, it can produce 5 seeds. If only 3 ovules are fertilised, only 3 seeds will form.

Importance of Reproduction in Plants for Class 7 Students

Reproduction is vital for plants to:

• Continue their species.
• Adapt to changing environments.
• Provide food, oxygen, and raw materials for humans.

For Class 7 NCERT exams, understanding reproduction helps in answering questions on plant life cycles, seed formation, and methods of propagation. It also builds a foundation for higher classes in biology.