Which one of the following microorganisms forms symbiotic assocation with plants and helps them in their nutrition?

Options

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

Explanation

To answer the question, "Which one of the following microorganisms forms symbiotic association with plants and helps them in their nutrition?", we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Options**: The question provides four options:
- A) Glomus
- B) Azotobacter
- C) Klebsiella
- D) Azospirillum

2. **Understand Symbiotic Association**: Symbiotic association refers to a close and long-term biological interaction between two different species. This can involve mutualism, where both species benefit.

3. **Analyze Each Option**:
- **Glomus**: This is a genus of arbuscular mycorrhizal fungi that forms symbiotic relationships with plant roots, helping them absorb water and nutrients, particularly phosphorus.
- **Azotobacter**: This is a free-living nitrogen-fixing bacterium, but it does not form a symbiotic relationship with plants.
- **Klebsiella**: This is a genus of bacteria that does not have a known symbiotic relationship with plants.
- **Azospirillum**: This is a nitrogen-fixing bacterium that can associate with plant roots but does not form a true symbiotic relationship like mycorrhizae.

4. **Determine the Correct Answer**: Based on the analysis, Glomus is the only microorganism listed that forms a symbiotic association with plants and aids in their nutrition.

5. **Conclusion**: Therefore, the correct answer is **A) Glomus**.