HORTICULTURE

Detailed explanation-1: -The enzyme responsible for primary carboxylation in C3 plants is RuBP carboxylase-oxygenase. It stands for Ribulose Bisphosphate Carboxylase-Oxygenase. It is formed of a five-carbon ketose sugar-Ribulose bisphosphate (RuBP). It is the most abundant enzyme on the earth.

Detailed explanation-2: -Final answer: Carboxylation in the C3 plants requires the enzyme RuBisCO.

Detailed explanation-3: -RuBisCO is essential for carbon fixation in C3, C4 and CAM plants. It is present in the mesophyll and bundle sheath cells. It catalyses the carbon fixation reaction in the Calvin cycle, i.e. carboxylation of RuBP.

Detailed explanation-4: -Location: In C3 plants, RuBisCO occurs in mesophyll cells, whereas in C4 plants RuBisCO is present in bundle sheath cells.