Consider the following organisms :
- Agaricus
- Nostoc
- Spirogyra
Which of the above is/are used as biofertilizer/biofertilizers?
Smart Elimination
When you see biofertilizer, pick organisms that: Live in soil, Interact symbiotically with plants and Contribute nutrients.
Biofertilizers mostly involve Nitrogen Fixation. Cyanobacteria (Nostoc, Anabaena) are famous for this.
Agaricus is a Mushroom. Mushrooms are fungi that eat dead decaying matter; they don't capture energy/nutrients from the air to ""fertilize"" soil like algae do. Eliminate 1.
Spirogyra is a common pond algae (green silk) without this ability. Eliminate 3.
Potential Trap
Agaricus is a mushroom (fungi), Spirogyra is an algae, but are they biofertilizers?
Answer Key & Explanation
Answer: BThe correct answer is Option B.
Analysis:
- Agaricus: It is a genus of mushrooms (Fungi). It is edible but not used as a biofertilizer to fix nitrogen. (Incorrect)
- Nostoc: It is a Cyanobacteria (Blue-Green Algae) capable of fixing atmospheric nitrogen. It is widely used as a biofertilizer. (Correct)
- Spirogyra: It is a free-floating green algae. It does not fix nitrogen and is not used as a biofertilizer. (Incorrect)
Value Addition
- Other Biofertilizers: Rhizobium, Azotobacter, Azospirillum, Anabaena.
- Mycorrhiza: Fungal association aiding phosphorus absorption.
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Foundational question based on core concepts.