What is the ploidy of the cells of endosperm

Answer

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

### Step-by-Step Solution:

1. **Understand Double Fertilization**:
- In angiosperms (flowering plants), a unique process called double fertilization occurs. This involves two fertilization events.

2. **Identify the First Fertilization Event (Syngamy)**:
- The first male gamete from the pollen grain fuses with the egg cell, resulting in the formation of a zygote.
- Since both the male gamete and the egg cell are haploid (n), the zygote formed is diploid (2n).

3. **Identify the Second Fertilization Event (Triple Fusion)**:
- The second male gamete fuses with two polar nuclei present in the central cell of the ovule.
- The fusion of the two polar nuclei (n + n) results in a diploid secondary nucleus (2n).

4. **Formation of the Primary Endosperm Cell**:
- The diploid secondary nucleus then fuses with the second haploid male gamete (n), resulting in the formation of a primary endosperm cell.
- This primary endosperm cell is triploid (3n) because it contains one set of chromosomes from the second male gamete and two sets from the polar nuclei.

5. **Mitosis of the Primary Endosperm Cell**:
- The primary endosperm cell (3n) undergoes mitosis to produce the cells of the endosperm, which are also triploid (3n).

### Conclusion:
- Therefore, the ploidy of the cells of the endosperm is triploid (3n).

---