Question

$C_4$ plants are more efficient in photosynthesis at higher temperature due to presence of

• A. Bundle sheath
• B. Pyruvic phasphate dikinase
• C. Well differentiated mesophyll
• D. Agrannel plastids in bundle sheath

Answer 1

The correct option is A Bundle sheath

The C${}_4$ plants show kranz anatomy with their vascular bundles being surrounded by two cellular rings i.e., bundle sheath cells (inner) and mesophyll cells (outer). The main function of this anatomy is to provide a site in which CO${}_2$ can be concentrated around RuBisCO, that is to maintain a higher concentration of CO${}_2$ in the bundle sheath compared to the mesophyll. This happens as the boundary layer of the kranz has a low conductance to CO${}_2$, thereby avoiding photorespiration. Therefore, C${}_4$ plants are able to more efficiently fix carbon in drought, high temperatures, and limitations of nitrogen or CO${}_2$.

So the correct option is 'Bundle sheath'