A pistillate flower of tetraploid angiosperm is pollinated by pollen from staminate flower of diploid plant. What would be the ploidy iin endosperm of seeds thus formed ?

Options

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

Answer

To determine the ploidy of the endosperm in the seeds formed from a pistillate flower of a tetraploid angiosperm pollinated by pollen from a staminate flower of a diploid plant, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Ploidy Levels**:
- The pistillate flower is tetraploid (4n).
- The staminate flower is diploid (2n).

2. **Understand the Formation of Gametes**:
- In the tetraploid flower (4n), meiosis occurs to produce megaspores. Since it is tetraploid, the megaspores formed will be diploid (2n).
- The megaspore undergoes three mitotic divisions to form the female gametophyte, which includes:
- One egg cell (2n)
- Two synergids (2n)
- Three antipodal cells (2n)
- One central cell with two polar nuclei (2n + 2n = 4n)

3. **Double Fertilization Process**:
- The pollen grain from the diploid plant (n) will fertilize the egg cell (2n) and also the central cell (which contains two polar nuclei).
- The fertilization of the egg cell results in a zygote with a ploidy of 3n (2n from the egg + 1n from the pollen).
- The fertilization of the central cell (which has two polar nuclei) will yield the endosperm.

4. **Calculate the Ploidy of the Endosperm**:
- The central cell has two polar nuclei (2n), and it is fertilized by the pollen grain (n).
- Therefore, the endosperm will have a ploidy of 2n + n = 3n.

5. **Final Answer**:
- The ploidy of the endosperm formed in the seeds is 5n (4n from the central cell and 1n from the pollen).

### Conclusion:
The ploidy in the endosperm of the seeds formed will be **5n**.