If the stock contains 48 chromosomes and the scion contains 30 chromosomes , then how many chromosomes are present in the root and egg cell of the resultant plant , respectively ?

Options

A. 48 and 15
B. 15 and 48
C. 30 and 24
D. 24 and 15

Answer

To solve the problem, we need to understand the concepts of plant grafting and how chromosome numbers are affected in different parts of the plant.

### Step-by-Step Solution:

1. **Identify the Chromosome Number in Stock and Scion:**
- The stock (root part) has 48 chromosomes.
- The scion (vegetative part) has 30 chromosomes.

2. **Understand the Process of Grafting:**
- In grafting, the root system (stock) and the upper part (scion) of two different plants are joined together. The root system remains intact and retains its chromosome number.

3. **Determine the Chromosome Number in the Root:**
- Since the root comes from the stock, it retains its chromosome number of 48. There is no meiosis occurring in the root, so the chromosome number remains unchanged.

4. **Determine the Chromosome Number in the Egg Cell:**
- The egg cell is produced from the scion, which undergoes meiosis. Meiosis reduces the chromosome number by half.
- Therefore, the egg cell will have half of the scion's chromosome number:
\[ \text{Egg cell chromosomes} = \frac{30}{2} = 15 \]

5. **Conclusion:**
- The root of the resultant plant has 48 chromosomes.
- The egg cell of the resultant plant has 15 chromosomes.

### Final Answer:
- The number of chromosomes present in the root and egg cell of the resultant plant are **48** and **15**, respectively.