If the male plant is tetraploid and female plant is diploid, what will be the ploidy level of endosperm after fertilization ?

Options

A. 3n
B. 4n
C. 5n
D. 6n

Answer

To determine the ploidy level of the endosperm after fertilization when the male plant is tetraploid (4n) and the female plant is diploid (2n), we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Ploidy Levels**:
- The male plant is tetraploid, which means it has 4 sets of chromosomes (4n).
- The female plant is diploid, meaning it has 2 sets of chromosomes (2n).

2. **Gametogenesis**:
- During gametogenesis (the formation of gametes), the tetraploid male plant will produce haploid gametes. Since the male plant is 4n, the gametes produced will have half the chromosome number, which is 2n.
- The diploid female plant will also produce haploid gametes, which will have 1n (n represents the haploid number).

3. **Double Fertilization**:
- In angiosperms, double fertilization occurs. This involves two fertilization events:
- **Syngamy**: The fusion of one male gamete (1n) with the female gamete (1n) to form the zygote (2n).
- **Triple Fusion**: The fusion of the second male gamete (1n) with the diploid secondary nucleus (2n) in the ovule to form the endosperm.

4. **Formation of Endosperm**:
- The endosperm is formed by the fusion of the second male gamete (1n) and the diploid secondary nucleus (2n).
- Therefore, the ploidy level of the endosperm can be calculated as:
\[ \text{Endosperm ploidy} = 1n + 2n = 3n \]

5. **Conclusion**:
- The ploidy level of the endosperm after fertilization will be triploid (3n).

### Final Answer:
The ploidy level of the endosperm after fertilization is **3n**.

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