Question

What is the role of large bundle sheath cells found around the vascular bundles in \(C_4\) plants?

• A. To provide the site of photorespiratory pathway
• B. To increase the number of chloroplast for the operation of Calvin cycle
• C. To enable the plant to tolerate high temperature
• D. To protect the vascular tissue from high light intensity

Answer 1

The Correct Option is B

Role of Large Bundle Sheath Cells in \(C_4\) Plants:

The large bundle sheath cells found around the vascular bundles in \(C_4\) plants have an essential role in the photosynthesis process. These cells are integral in the Calvin cycle, a series of biochemical redox reactions that convert carbon dioxide and other compounds into glucose.

1. Location: The bundle sheath cells encase the vascular bundles, forming a protective layer around them. This spatial arrangement is critical for the compartmentalization of the photosynthetic processes.

2. Number of Chloroplasts: One of the primary functions of these cells is to house a large number of chloroplasts. The abundance of chloroplasts is crucial because it provides a significant surface area for the Calvin cycle reactions, enhancing the plant's ability to fix carbon efficiently.

3. Biochemical Role: In \(C_4\) plants, carbon fixation is divided into two structurally distinct cell types — mesophyll cells and bundle sheath cells. Initially, carbon dioxide is fixed in the mesophyll cells and converted into a four-carbon compound (malate), which is then transported into bundle sheath cells. Here, carbon dioxide is released for the Calvin cycle.

4. Adaptation: This anatomical and biochemical adaptation allows \(C_4\) plants to photosynthesize more efficiently in high-temperature and low-carbon dioxide environments. The arrangement minimizes photorespiration, a wasteful pathway that competes with photosynthesis, especially under such conditions.

5. Conclusion: Therefore, the correct answer to the question regarding the role of the bundle sheath cells in \(C_4\) plants is: To increase the number of chloroplast for the operation of Calvin cycle.