Biofertilizer organism which occurs both on rhizoplane as well as in the rhizosphere of cereal crops

Options

A. Rhizobium
B. Azospirillum
C. Azotobacter
D. Glomus

Answer

**Step-by-Step Solution:**

1. **Understand the Question**: The question asks for a biofertilizer organism that is found both on the rhizoplane and in the rhizosphere of cereal crops.

2. **Define Key Terms**:
- **Rhizoplane**: This is the surface of the root where microorganisms can attach.
- **Rhizosphere**: This is the region of soil that is influenced by the roots of the plant, where a high concentration of microorganisms exists.

3. **Analyze the Options**: The options given are:
- **Rhizobium**: A nitrogen-fixing bacteria typically associated with leguminous plants.
- **Azospirillum**: A nitrogen-fixing bacteria that is known to associate with cereal crops.
- **Acetobacter**: A nitrogen-fixing bacteria that is more common in non-leguminous plants.
- **Glomus**: A type of mycorrhizal fungi that forms symbiotic relationships with many plants.

4. **Evaluate Each Option**:
- **Rhizobium**: Primarily found in leguminous plants, not cereal crops.
- **Azospirillum**: Known to inhabit both the rhizoplane and rhizosphere of cereal crops, making it a strong candidate.
- **Acetobacter**: Typically associated with non-leguminous plants, not specifically with cereal crops.
- **Glomus**: While it forms symbiotic relationships, it is not specifically a biofertilizer for cereal crops.

5. **Select the Correct Answer**: Based on the analysis, **Azospirillum** is the biofertilizer organism that occurs both on the rhizoplane and in the rhizosphere of cereal crops.

6. **Final Answer**: The correct answer is **Azospirillum** (Option B).

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