In maize , a meiocyte has 20 chromosomes . What will be the number of chromosomes in its vegetative of pollen grain and nucellus cell of ovule respectively?

Options

A. 20,40
B. 20,10
C. 10,20
D. 40,20

Answer

To solve the question regarding the number of chromosomes in the vegetative cell of the pollen grain and the nucellus cell of the ovule in maize, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Chromosome Number in Meiocyte**:
- The question states that a meiocyte in maize has 20 chromosomes. This meiocyte is diploid (2n), meaning it contains two sets of chromosomes.

2. **Determine the Chromosome Number in Gametes**:
- During meiosis, the meiocyte undergoes two rounds of cell division to produce four haploid (n) gametes. Since the meiocyte is diploid with 20 chromosomes, each gamete will have half the number of chromosomes.
- Therefore, the number of chromosomes in each gamete = 20 chromosomes (meiocyte) / 2 = 10 chromosomes.

3. **Identify the Chromosome Number in the Vegetative Cell of Pollen Grain**:
- The vegetative cell of the pollen grain is derived from the haploid gamete. Thus, it also contains 10 chromosomes (haploid).

4. **Determine the Chromosome Number in the Nucellus Cell of the Ovule**:
- The nucellus is part of the ovule and is diploid. Since the meiocyte is diploid with 20 chromosomes, the nucellus cell will also have 20 chromosomes.

5. **Summarize the Findings**:
- The number of chromosomes in the vegetative cell of the pollen grain = 10 chromosomes.
- The number of chromosomes in the nucellus cell of the ovule = 20 chromosomes.

### Final Answer:
- The number of chromosomes in the vegetative cell of the pollen grain is 10, and in the nucellus cell of the ovule, it is 20.