In `C_4` plants , the Calvin pathway takes place in

Options

A. mesophyll cells only
B. both mesophyll and bundle sheath cells
C. bundle sheath cells only
D. cells of the vascular bundles

Answer

To solve the question regarding where the Calvin pathway takes place in C4 plants, we can follow these steps:

### Step-by-Step Solution:

1. **Understand C4 Plants**: C4 plants have a unique photosynthetic pathway that allows them to efficiently fix carbon dioxide, especially in hot and dry environments. Examples include maize and sugarcane.

2. **Identify Key Structures**: In C4 plants, there are two types of cells involved in photosynthesis: Mesophyll cells and Bundle Sheath cells.

3. **Function of Mesophyll Cells**: Mesophyll cells are where the initial carbon fixation occurs. In C4 plants, carbon dioxide is first fixed into a 4-carbon compound (C4 acid) using phosphoenolpyruvate (PEP) as the primary CO2 acceptor.

4. **Function of Bundle Sheath Cells**: The C4 acid produced in the mesophyll cells is then transported to the Bundle Sheath cells, where the Calvin cycle occurs. This is where the actual synthesis of sugars takes place, utilizing ATP and NADPH produced from the light reactions.

5. **Conclusion**: The Calvin cycle, which is the dark reaction of photosynthesis, occurs in the Bundle Sheath cells of C4 plants.

### Final Answer:
The Calvin pathway takes place in **Bundle Sheath cells** of C4 plants.