First haploid cell of female gameophyte is

Options

A. Functional megaspore
B. Microspore mother cell
C. Megaspore mother cell
D. None of the above.

Answer

To solve the question regarding the first haploid cell of the female gametophyte, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Terms**:
- The female gametophyte develops from a structure called the megasporangium, which contains the megaspore mother cell (also known as the megasporocyte).

2. **Identifying the Megaspore Mother Cell**:
- The megaspore mother cell is diploid (2n) and is located within the nucellus of the ovule.

3. **Meiotic Division**:
- The megaspore mother cell undergoes meiosis, which is a type of cell division that reduces the chromosome number by half. This process results in the formation of four haploid megaspores.

4. **Functional Megaspore**:
- Out of the four haploid megaspores formed, three degenerate, leaving only one functional megaspore. This functional megaspore is the first haploid cell of the female gametophyte.

5. **Further Development**:
- The functional megaspore then undergoes mitotic divisions (specifically three rounds of mitosis) without cytokinesis, resulting in eight nuclei.

6. **Formation of the Embryo Sac**:
- These eight nuclei arrange themselves to form the embryo sac, which is the mature female gametophyte structure.

7. **Conclusion**:
- Therefore, the first haploid cell of the female gametophyte is the functional megaspore.

### Final Answer:
The first haploid cell of the female gametophyte is the **functional megaspore**.

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