The innermost wall layer of microsporangium is called.

Options

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

Answer

To determine the innermost wall layer of the microsporangium, we can follow these steps:

1. **Understand the Structure of Microsporangium**: The microsporangium is a part of the plant's reproductive system where pollen grains are developed. It has several layers.

2. **Identify the Wall Layers**: The wall layers of the microsporangium are arranged from the outermost to the innermost. The layers are:
- **Epidermis**: This is the outermost layer.
- **Endothecium**: This layer is located just beneath the epidermis.
- **Middle Layers**: There are typically one to three middle layers.
- **Tapetum**: This is the innermost layer.

3. **Eliminate Incorrect Options**:
- **Epidermis** is the outermost layer, so it cannot be the correct answer.
- **Endothecium** is the second layer, which also cannot be the correct answer.
- The **middle layers** are between the endothecium and the tapetum, which means they are not the innermost layer.

4. **Identify the Correct Answer**: The innermost wall layer of the microsporangium is the **tapetum**. The tapetum plays a crucial role in providing nourishment to the developing pollen grains.

5. **Conclusion**: Therefore, the correct answer to the question is **tapetum**.