What is the role of large bundle sheath cells found around the vascular bundles in C4 plants?
Answer: (B) To increase the number of chloroplast for the operation of Calvin cycle. In C4 plants the large bundle sheath cells around the vascular bundles (Kranz anatomy) are packed with a large number of chloroplasts.
- 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
Correct Answer
(B) To increase the number of chloroplast for the operation of Calvin cycle
Solution & Explanation
In C4 plants the large bundle sheath cells around the vascular bundles (Kranz anatomy) are packed with a large number of chloroplasts. The CO2 released here from the breakdown of C4 acids enters the Calvin (C3) cycle, which in C4 plants operates only in the bundle sheath cells. Hence their role is to provide the chloroplast-rich site for the operation of the Calvin cycle. Option A is wrong because C4 plants avoid photorespiration. NCERT: Class 11 Ch 11, p.145 [145:038-039]: "they are characterised by having a large number of chloroplasts"