The function of innermost layer of pollen sac, tapetum is

Options

A. Protection
B. Nutrition
C. Dehiscence
D. Mechanical strength.

Answer

**Step-by-Step Solution:**

1. **Identify the Layers of the Pollen Sac**: The pollen sac, also known as the microsporangium, has several layers. The outermost layer is the epidermis, followed by the endothecium, middle layers, and the innermost layer, which is the tapetum.

2. **Understand the Function of Each Layer**:
- **Epidermis**: This outer layer primarily provides protection to the pollen sac.
- **Endothecium**: This layer also offers protection and plays a role in the dehiscence (breaking open) of the anther when it matures.
- **Middle Layers**: These layers serve a protective function as well.

3. **Focus on the Tapetum**: The tapetum is the innermost layer of the pollen sac. Its primary function is to nourish the developing pollen grains. It provides essential nutrients that are crucial for the viability of the pollen grains.

4. **Consequences of Non-Functional Tapetum**: If the tapetum is non-functional, the pollen grains produced may be non-viable due to a lack of proper nutrition. This highlights the importance of the tapetum in pollen development.

5. **Conclusion**: Based on the functions of the layers, the correct answer to the question about the function of the tapetum is that it nourishes the pollen grains.

**Final Answer**: The function of the innermost layer of the pollen sac, the tapetum, is to nourish the pollen grains.

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