Primary parietal cells of a young pollen sac form

Options

A. Sporocytes
B. Epidermis
C. Microsporangial wall inner to epidermis
D. Microsporangial wall including the epidermis.

Explanation

To solve the question regarding what the primary parietal cells of a young pollen sac form, we can break down the information step by step:

### Step-by-Step Solution:

1. **Understanding the Young Anther Structure**:
- A young anther consists of four layers. The outermost layer is the epidermis.

2. **Identifying Primary Parietal Cells**:
- Beneath the epidermis, there are cells known as Arcus Aureal Cells, which have prominent nuclei and dense cytoplasm. These cells undergo preclinical division to form a group of cells called primary parietal cells.

3. **Division of Primary Parietal Cells**:
- The primary parietal cells further divide and differentiate into secondary parietal cells.

4. **Formation of the Microsporangial Wall**:
- The outer layer of the secondary parietal cells differentiates to form the endothelium. The inner layer of the secondary parietal cells divides again, leading to the formation of two layers: one forms the middle layer and the other forms the tapetum.

5. **Conclusion**:
- Therefore, the primary parietal cells ultimately contribute to forming the microsporangial wall, which is located inner to the epidermis.

### Final Answer:
The primary parietal cells of a young pollen sac form the microsporangial wall inner to the epidermis.

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