What is the ploidy of primary endosperm nucleus is ____

Answer

To determine the ploidy of the primary endosperm nucleus, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Double Fertilization**:
- In angiosperms, double fertilization is a unique process that involves two fertilization events.

2. **First Fertilization Event**:
- The first male gamete (haploid, N) fuses with the egg cell (haploid, N) in the embryo sac.
- This fusion results in the formation of a zygote, which is diploid (2N).

3. **Second Fertilization Event (Triple Fusion)**:
- The second male gamete (haploid, N) fuses with the central cell, which is a diploid structure (2N) formed by the fusion of two polar nuclei (N + N).
- This fusion results in the formation of the primary endosperm cell.

4. **Determining the Ploidy of the Primary Endosperm Cell**:
- The primary endosperm cell is formed by the fusion of one haploid male gamete (N) with a diploid central cell (2N).
- Therefore, the ploidy of the primary endosperm cell is 3N (triploid).

5. **Conclusion**:
- The ploidy of the primary endosperm nucleus is triploid (3N).

### Final Answer:
The ploidy of the primary endosperm nucleus is **triploid (3N)**.

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