A diploid female plant and a tetraploid male plant are crossed. The ploidy of endosperm shall be

Options

A. Pentaploidy
B. Diploidy
C. Triploidy
D. Tetraploidy

Answer

To determine the ploidy of the endosperm resulting from the cross between a diploid female plant and a tetraploid male plant, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Ploidy of the Parent Plants:**
- The female plant is diploid (2n).
- The male plant is tetraploid (4n).

2. **Determine the Ploidy of the Gametes:**
- The female plant (2n) will produce haploid gametes (n) through meiosis.
- The male plant (4n) will produce diploid gametes (2n) through meiosis.

3. **Understand the Formation of the Endosperm:**
- The endosperm is formed by the fusion of two polar nuclei and one male gamete.
- The two polar nuclei (from the female) contribute a total of 2n (since each polar nucleus is n).

4. **Calculate the Ploidy of the Endosperm:**
- The endosperm is formed by the fusion of:
- 2 polar nuclei (2n) + 1 male gamete (2n).
- Therefore, the total ploidy of the endosperm will be:
- 2n (from polar nuclei) + 2n (from male gamete) = 4n.

5. **Conclusion:**
- The ploidy of the endosperm resulting from the cross between a diploid female plant and a tetraploid male plant is tetraploid (4n).

### Final Answer:
The ploidy of the endosperm shall be tetraploidy (4n).

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