True symbiotic association between fungus and seed plant is

Options

A. Endomycorrhiza
B. Ectomycorrhiza
C. Helotism
D. Commensalism

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks for the true symbiotic association between a fungus and a seed plant.

2. **Identifying the Options**: The options provided are:
- Option 1: Endomycorrhiza
- Option 2: Ectomycorrhiza
- Option 3: Helotism
- Option 4: Commensalism

3. **Defining Mycorrhizae**: Mycorrhizae refers to the mutual symbiotic association between fungi and plants. In this relationship, both the fungus and the plant benefit from each other.

4. **Types of Mycorrhizae**:
- **Ectomycorrhizae**: These fungi form an external association with plant roots. They grow around the root cells but do not penetrate the cell walls.
- **Endomycorrhizae**: These fungi penetrate the root cell walls and enter the cells of the host plant, forming a more invasive and intimate relationship.

5. **Analyzing the Options**:
- **Option 1 (Endomycorrhiza)**: This is a true symbiotic association where the fungus enters the plant cells, benefiting both organisms.
- **Option 2 (Ectomycorrhiza)**: While this is also a type of mycorrhiza, it does not represent a true symbiotic relationship as it does not penetrate the cells.
- **Option 3 (Helotism)**: This is a relationship where one organism acts as a slave to another, which is not relevant here.
- **Option 4 (Commensalism)**: This describes a relationship where one organism benefits while the other is neither helped nor harmed, which does not fit the definition of a mutual symbiotic association.

6. **Conclusion**: Based on the definitions and analysis, the correct answer is **Option 1: Endomycorrhiza**. This represents a true symbiotic association between a fungus and a seed plant.