. In Pinus, endosperm cells have 30 chromosomes then how many chromosomes are present in sieve cells :-

Options

A. 30
B. 60
C. 10
D. 15

Answer

To solve the question regarding the number of chromosomes present in sieve cells of Pinus when the endosperm cells have 30 chromosomes, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Organism**: Pinus is a genus of gymnosperms, which are non-flowering plants that produce seeds without a fruit.

2. **Identify the Chromosome Count in Endosperm**: The question states that the endosperm cells in Pinus have 30 chromosomes.

3. **Determine the Nature of Endosperm**: In gymnosperms like Pinus, the endosperm is not a true endosperm as seen in angiosperms. It is formed before fertilization and is typically haploid (1n).

4. **Chromosome Count in Sieve Cells**: Sieve cells are part of the phloem and are responsible for the transport of nutrients. In gymnosperms, sieve cells are diploid (2n), meaning they contain two sets of chromosomes.

5. **Calculate the Chromosome Number in Sieve Cells**: Since the endosperm is haploid with 30 chromosomes (1n), the corresponding diploid sieve cells would have double that number. Therefore, the number of chromosomes in sieve cells would be:
\[ \text{Number of chromosomes in sieve cells} = 2 \times 30 = 60 \]

6. **Conclusion**: The number of chromosomes present in sieve cells of Pinus is 60.

### Final Answer:
The number of chromosomes present in sieve cells is **60**.

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