Main photosynthetic organ of Nepenthes.

Options

A. Upper petiole
B. Lower petiole
C. Modified lamina
D. Leaf apex

Answer

### Step-by-Step Solution:

1. **Understanding Nepenthes**: Nepenthes, commonly known as pitcher plants, are carnivorous plants that have adapted to nutrient-poor environments. They trap and digest insects to obtain nutrients, which supplement their photosynthetic capabilities.

2. **Identifying the Photosynthetic Organ**: In Nepenthes, the main organ responsible for photosynthesis is crucial for the plant's survival. While the plant has various structures, we need to identify which one primarily carries out photosynthesis.

3. **Examining the Structures**:
- **Upper Petiole**: This part of the plant forms tendrils that help the plant climb. It is not primarily responsible for photosynthesis.
- **Lower Petiole**: This structure has small leaf-like appendages that contribute to photosynthesis. It plays a significant role in the plant's ability to convert sunlight into energy.
- **Modified Lamina**: This part produces the pitcher-like structure that traps insects but does not carry out photosynthesis.
- **Leaf Apex**: This structure forms the covering of the pitcher and is not involved in photosynthesis.

4. **Conclusion**: After analyzing the functions of each part, the lower petiole is identified as the main photosynthetic organ of Nepenthes due to its leaf-like structures that facilitate photosynthesis.

5. **Final Answer**: The main photosynthetic organ of Nepenthes is the **lower petiole**.