Which is not a modification of stem ?

Options

A. Tuber of potato
B. Pitcher of Nepenthes
C. Corm of Colocasia
D. Rhizome of ginger

Answer

To solve the question "Which is not a modification of stem?", we need to analyze the given options one by one to identify which one does not represent a modification of the stem.

### Step-by-Step Solution:

1. **Understand the Concept of Stem Modifications**:
- Stem modifications are adaptations of the stem that serve various functions such as storage, support, or reproduction. Examples include tubers, rhizomes, and corms.

2. **Analyze the First Option - Tuber of Potato**:
- The tuber of potato is a swollen part of the stem that stores nutrients. It is indeed a modification of the stem.
- **Conclusion**: This option is incorrect as it is a modification of the stem.

3. **Analyze the Second Option - Pitcher of Nepenthes Khaziana**:
- The pitcher plant (Nepenthes Khaziana) has leaves that are modified into pitcher-shaped structures to trap insects. This is a modification of the leaf, not the stem.
- **Conclusion**: This option is correct as it is not a modification of the stem.

4. **Analyze the Third Option - Corm of Colocasia**:
- The corm of Colocasia is a swollen underground stem that stores nutrients and can give rise to new plants. This is a modification of the stem.
- **Conclusion**: This option is incorrect as it is a modification of the stem.

5. **Analyze the Fourth Option - Rhizome of Ginger**:
- The rhizome of ginger is a horizontal stem that grows underground and can produce new plants. This is also a modification of the stem.
- **Conclusion**: This option is incorrect as it is a modification of the stem.

### Final Answer:
The correct answer is the **second option - Pitcher of Nepenthes Khaziana**, as it is not a modification of the stem.

---