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

Options

A. Trichoderma
B. Azotobacter
C. Aspergillus
D. Glomus

Answer

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

### Step 1: Understand the concept of symbiotic association
Symbiotic association refers to a relationship between two organisms where both benefit from each other. In the context of plants, certain microbes form symbiotic relationships that enhance the plant's ability to absorb nutrients.

### Step 2: Analyze the options provided
1. **Trichoderma**: This is a genus of fungi, specifically Trichoderma polysporum. While it has beneficial uses, it does not form a symbiotic relationship with plants for nutrition.

2. **Azotobacter**: This is a free-living bacterium that fixes nitrogen in the soil. Although it contributes to soil fertility, it does not form a symbiotic relationship with plants.

3. **Aspergillus**: This is another type of fungus, known for causing diseases in plants, such as Black Mold Disease. It does not have a beneficial symbiotic relationship with plants.

4. **Glomus**: This is a genus of fungi that forms mycorrhizal associations with plant roots. In this relationship, the fungus helps the plant absorb water and nutrients (especially phosphorus) from the soil, while the plant provides carbohydrates to the fungus.

### Step 3: Identify the correct answer
Based on the analysis, the correct answer is **Glomus**, as it forms a symbiotic association with plants and aids in their nutrition.

### Final Answer:
**Glomus**

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