In Angiosperm, if number of chromosomes in endosperm is 30, what will be the no. of chromosomes in nucellus :-

Options

A. 15
B. 30
C. 20
D. 40

Answer

To solve the question regarding the number of chromosomes in the nucellus when the number of chromosomes in the endosperm is given as 30, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Structure of Endosperm**:
- In angiosperms (flowering plants), the endosperm is a triploid structure. This means that it has three sets of chromosomes.

2. **Identify the Ploidy of Endosperm**:
- The endosperm is formed by the fusion of one male gamete with the diploid secondary nucleus (which is formed from the fusion of two polar nuclei). Therefore, the endosperm has a ploidy level of 3n.

3. **Set Up the Equation**:
- According to the question, the number of chromosomes in the endosperm is 30. Thus, we can write:
\[ 3n = 30 \]

4. **Calculate the Value of n**:
- To find the value of n (the haploid number of chromosomes), we divide both sides of the equation by 3:
\[ n = \frac{30}{3} = 10 \]

5. **Determine the Ploidy of Nucellus**:
- The nucellus is a diploid structure, which means it has a ploidy level of 2n. Since we have already determined that n = 10, we can calculate:
\[ 2n = 2 \times 10 = 20 \]

6. **Conclusion**:
- Therefore, the number of chromosomes in the nucellus is 20.

### Final Answer:
The number of chromosomes in the nucellus is **20**.

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