Question

In $C_4$ plants, initial $C{O}_2$ fixation takes place in the chloroplasts of

• A. guard cells
• B. spongy mesophyll
• C. palisade tissue
• D. bundle sheath

Answer 1

Answer: (B)

In the leaves of $C_4$-plants the vascular bundles are surrounded by bundle sheath of large parenchymatous cells, which in turn are surrounded by mesophyll cells. Chloroplast in bundle sheath cells are larger and always contain grana. Whereas, chloroplast in mesophyll cells are smaller. In maize and sugarcane plasmodesmata are present, which connect cells of bundle sheath with mesophyll cells.