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Reproduction in Plants - Asexual Reproduction: Budding, Fragmentation, and Spore Formation

Grade 7CBSE

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

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Asexual reproduction is a method where new plants are obtained without the production of seeds, involving only a single parent.

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Budding: This process is common in unicellular organisms like Yeast. A small bulb-like projection, called a bud, grows out from the parent cell. The nucleus divides, and one daughter nucleus moves into the bud. Eventually, the bud detaches and matures into a new yeast cell.

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Fragmentation: In certain algae like SpirogyraSpirogyra, the organism breaks up into two or more fragments. Each fragment then grows into a complete new individual. This process allows for rapid multiplication in stagnant water.

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Spore Formation: Fungi (like bread mould) and non-flowering plants (like ferns and mosses) reproduce via spores. Spores are tiny, asexual reproductive bodies covered by a hard protective coat to withstand unfavorable conditions such as high temperature and low humidity.

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Germination of Spores: When conditions become favorable (availability of moisture and nutrients), a spore germinates and develops into a new individual plant.

📐Formulae

Parent Cell→GrowthBud→SeparationNew Organism\text{Parent Cell} \xrightarrow{\text{Growth}} \text{Bud} \xrightarrow{\text{Separation}} \text{New Organism}

Algal Filament→Fragmentationn×New Individuals\text{Algal Filament} \xrightarrow{\text{Fragmentation}} n \times \text{New Individuals}

Spore+Moisture+Nutrients→Germination\text{Spore} + \text{Moisture} + \text{Nutrients} \rightarrow \text{Germination}

💡Examples

Problem 1:

If a single SpirogyraSpirogyra filament breaks into 44 pieces, how many new individuals will be formed?

Solution:

44 new individuals.

Explanation:

In the process of fragmentation, every piece or fragment that breaks off from the parent body has the capability to grow into a complete, independent organism.

Problem 2:

Why can spores survive for a long period in the air even during extreme summer heat?

Solution:

Due to their hard protective coat.

Explanation:

Each spore is surrounded by a thick, resistant wall that protects it from dehydration and high temperatures, allowing it to remain dormant until favorable conditions return.

Problem 3:

Observe a yeast cell under a microscope. You see a chain of small cells attached to a larger one. What is this process called?

Solution:

Budding (specifically, forming a 'chain of buds').

Explanation:

In Yeast, if the supply of nutrients is abundant, the buds may not detach immediately. Instead, new buds grow on top of the first bud, forming a chain of yeast cells within a short time.