Differences between C3, C4 and CAM plants.

C3 PLANTS:

• Typical Species : Wheat, Rice
• Carboxylating enzyme: Rubisco
• First product of CO2 fixation: 3PGA (Phosphoglycerate)
• Leaf anatomy: Photosynthesis occurs in mesophyll. Bundle sheath may present.
• Present in: in temperate region, in all photosynthetic plants
• Initial CO2 acceptor: RuBP
• Photorespiration: High

C4 PLANTS:

• Typical Species : Maize, Sugarcane
• Carboxylating enzyme: Rubisco and PEP carboxylase (both active in dark, but at different compartments)
• First product of CO2 fixation: OAA (oxaloacetic acid)
• Leaf anatomy: Photosynthesis occurs in mesophyll and bundle sheath (Kranz anatomy)
• Present in: tropical plants
• Initial CO2 acceptor: PEP (phosphoenolpyruvate)
• Photorespiration: less

CAM PLANTS:

• Typical Species : Cactus, Pineapple
• Carboxylating enzyme: Rubisco in light and PEP carboxylase in dark
• First product of CO2 fixation: 3 PGA in light and OAA in dark.
• Leaf anatomy: Photosynthesis occurs in mesophyll contain large vacuoles for malic acid storage
• Present in: Semi-arid condition or in tropical rainforest
• Initial CO2 acceptor: PEP
• Photorespiration: least