Fusion of male gamete and definitive nucleus results in the formation of

Options

A. Primary endosperm cell
B. Primary endosperm nucleus
C. Zygote
D. Secondary nuclei

Answer

To solve the question regarding the fusion of the male gamete and the definitive nucleus, we can break it down into the following steps:

### Step-by-Step Solution:

1. **Understanding Gametes and Fertilization**:
- In flowering plants, during fertilization, the male gamete (pollen) is involved in the fusion process.

2. **Pollen Tube and Male Gametes**:
- When pollen lands on the stigma of a flower, it germinates and forms a pollen tube that carries two male gametes to the ovule.

3. **Fusion of Male Gametes**:
- One male gamete fuses with the egg cell (female gamete) to form the zygote. This is the first fertilization event.

4. **Fusion with Definitive Nucleus**:
- The second male gamete fuses with the two polar nuclei present in the central cell of the ovule. This fusion is crucial for the formation of the endosperm.

5. **Formation of Primary Endosperm Nucleus**:
- The fusion of the second male gamete with the two polar nuclei results in the formation of a diploid nucleus known as the primary endosperm nucleus (also referred to as the secondary nucleus).

6. **Conclusion**:
- Therefore, the correct answer to the question is that the fusion of the male gamete and the definitive nucleus results in the formation of the primary endosperm nucleus.

### Final Answer:
The fusion of the male gamete and the definitive nucleus results in the formation of the **primary endosperm nucleus**.