The innermost wall layer of microsporangia which provides nutrition to the developing pollen grain is

Options

A. Epidermis
B. Endothelium
C. Middle layer
D. Tapetum

Answer

To solve the question regarding the innermost wall layer of microsporangia that provides nutrition to the developing pollen grain, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Microsporangia Structure**:
- Microsporangia, which are the structures where pollen grains develop, have multiple layers in their wall. It is essential to know the names and functions of these layers.

2. **Identifying the Layers**:
- The wall of microsporangia consists of four layers:
- **Epidermis**: This is the outermost layer and serves as a protective covering.
- **Endothesium**: This layer develops fibrous thickening at maturity and is hygroscopic, aiding in the release of pollen.
- **Middle Layer**: This layer primarily stores reserve food material.
- **Tapetum**: This is the innermost layer of the microsporangia.

3. **Determining the Function of Each Layer**:
- **Epidermis**: Protective function, does not provide nutrition.
- **Endothesium**: Aids in pollen release, does not provide nutrition.
- **Middle Layer**: Stores food but does not directly nourish the developing pollen grains.
- **Tapetum**: Provides nutrition to the developing pollen grains, which is its primary function.

4. **Conclusion**:
- Based on the functions of the layers, the innermost wall layer of microsporangia that provides nutrition to the developing pollen grain is the **Tapetum**.

### Final Answer:
The innermost wall layer of microsporangia that provides nutrition to the developing pollen grain is the **Tapetum**.

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