In leaves of C4 plants malic acid synthesis during CO2 fixation occurs in
- bundle sheath
- guard cells
- epidermal cells
- mesophyll cells
Answer
(4) mesophyll cells
Solution
As per NCERT, the primary CO2 acceptor in C4 plants is phosphoenol pyruvate (PEP), present in the mesophyll cells, where the enzyme PEP carboxylase (PEPcase) is also present.
PEP combines with CO2 to give oxaloacetic acid (OAA), a 4-carbon acid (PEP + CO2 OAA).
In the mesophyll cells OAA then forms other 4-carbon acids such as malic acid or aspartic acid, which are transported to the bundle sheath cells.
Answer: (4)