Nucleus of megaspore divides mitotically from two nuclei which move to opposite poles and leter from an embryo sac which is

Options

A. 2- nucleate
B. 4- nucleate
C. 6- nucleate
D. 8- nucleate.

Answer

To solve the question regarding the formation of the embryo sac from the nucleus of the megaspore, we can break it down into the following steps:

### Step-by-Step Solution:

1. **Understanding Megasporogenesis**:
- The process begins with a megaspore mother cell (megaspore MMC) which undergoes meiosis. This results in the formation of four haploid megaspores.

2. **Degeneration of Megaspores**:
- Out of the four megaspores formed, three degenerate, leaving only one functional megaspore.

3. **Mitotic Division of the Functional Megaspore**:
- The remaining functional megaspore undergoes mitotic divisions. This is an equational division, meaning it maintains the haploid chromosome number.

4. **Formation of Nuclei**:
- The functional megaspore divides mitotically to produce two nuclei, which then divide again to form four nuclei, and finally, these nuclei divide once more to yield a total of eight nuclei.

5. **Arrangement of Nuclei**:
- The eight nuclei are arranged with four at each pole of the embryo sac. Two of these nuclei migrate to the center of the sac to form the central cell, which contains two polar nuclei.

6. **Final Structure of the Embryo Sac**:
- The final structure of the embryo sac consists of eight nuclei, leading to a total of seven cells (the central cell with two polar nuclei and the other five nuclei each forming individual cells).

7. **Conclusion**:
- Therefore, the embryo sac formed from the nucleus of the megaspore is **eight-nucleate**.

### Final Answer:
The embryo sac is **eight-nucleate**.

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