Question

A mother plant having 16 chromosomes produced ovules and underwent megasporogenesis, then the ploidy of the nucleus of A, B, C, D is: 

 

• A. A:16, B:16, C:8, D:16
• B. A:16, B:16, C:8, D:8
• C. A:16, B:32, C:8, D:8
• D. A:16, B:8, C:16, D:8

Hint:

In megasporogenesis, the mother cell is diploid, and after meiosis, the resulting megaspores are haploid.

Answer 1

The Correct Option is D

To solve this problem, we need to determine the ploidy of the nuclei A, B, C, and D formed after megasporogenesis, given that the mother plant has 16 chromosomes.

1. Understanding Megasporogenesis:
During megasporogenesis, a diploid (2n) mother cell undergoes meiosis to produce four haploid (n) megaspores. Each of these megaspores will have half the chromosome number of the original diploid parent cell. In this case, the mother plant has 16 chromosomes, meaning the diploid number (2n) is 16. Therefore, each haploid megaspore formed will have 8 chromosomes.

2. Analyzing the Options:
We need to understand the ploidy of the nuclei labeled A, B, C, and D. As the megaspore divides, the resulting nuclei will have the following ploidy levels:

• A: Since this is the first meiotic division, it is haploid (n), with 8 chromosomes.
• B: This is also haploid (n) because it originates from a meiotic process, and the chromosome count will be halved to 8.
• C: This will be haploid (n) as well, just like the others formed by the megasporogenesis process.
• D: This nucleus is also haploid (n), with 8 chromosomes as the result of meiosis.

3. Correct Answer:
The ploidy of the nuclei A, B, C, and D will be 8 chromosomes each, which corresponds to the haploid number (n).

Final Answer:
The correct option is Option D: A: 16, B: 8, C: 16, D: 8.

Answer 2

In megasporogenesis, the mother plant produces ovules, and each ovule undergoes meiosis. Meiosis reduces the chromosome number by half, leading to haploid gametes.
The nucleus of A and C will have the same ploidy as the mother plant (16 chromosomes).
Nucleus B will undergo meiosis, resulting in a haploid number (8 chromosomes).
Nucleus D, as a result of the second meiotic division, also has 8 chromosomes.