Question

In the leaves of $C_4$ plants, malic acid formed during $C{O}_2$ fixation occurs in the cells of

• A. Epidermis.
• B. Mesophyll.
• C. Bundle sheath.
• D. Phloem.

Answer 1

The correct option is B Mesophyll.

In $C_4$ plants the atmospheric carbon dioxide is temporarily fixed into four carbon organic acids in the mesophyll cells with the help of enzyme PEP carboxylase. The four carbon containing organic acids (malic acid or oxalic acid) are pumped into bundle sheath cells, where they are decarboxylated to release carbon dioxide. The released carbon dioxide is fixed by the enzyme RuBisCO in bundle sheath cells.