Why are C4 plants more efficient than C3 plants?

C4 plants use Kranz anatomy and PEP carboxylase to concentrate CO₂ around RuBisCO, which greatly reduces photorespiration and makes them more efficient, especially in hot, dry climates.

What is Kranz anatomy?

Kranz anatomy is the special leaf structure of C4 plants in which bundle-sheath cells with large chloroplasts surround the vascular bundles, allowing CO₂ to be concentrated for the Calvin cycle.

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Difference Between C₃ Plants and C₄ Plants

Plants fix carbon dioxide during photosynthesis by two main pathways - the C3 pathway and the more efficient C4 pathway.

In short

C₃ plants fix CO₂ directly via the Calvin cycle into a 3-carbon compound (3-PGA) and undergo photorespiration; C₄ plants first fix CO₂ into a 4-carbon compound (OAA) using Kranz anatomy, minimising photorespiration.

C₃ Plants vs C₄ Plants - Comparison Table

Basis	C₃ Plants	C₄ Plants
First stable product	3-PGA (3-carbon)	Oxaloacetic acid (4-carbon)
CO₂ acceptor	RuBP	PEP
Primary enzyme	RuBisCO	PEP carboxylase
Kranz anatomy	Absent	Present
Photorespiration	High	Very low / absent
Examples	Rice, wheat, soybean	Maize, sugarcane, sorghum

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Frequently Asked Questions - C₃ Plants vs C₄ Plants

Why are C4 plants more efficient than C3 plants?: C4 plants use Kranz anatomy and PEP carboxylase to concentrate CO₂ around RuBisCO, which greatly reduces photorespiration and makes them more efficient, especially in hot, dry climates.
What is Kranz anatomy?: Kranz anatomy is the special leaf structure of C4 plants in which bundle-sheath cells with large chloroplasts surround the vascular bundles, allowing CO₂ to be concentrated for the Calvin cycle.

Difference Between C₃ Plants and C₄ Plants

C₃ Plants vs C₄ Plants - Comparison Table

Frequently Asked Questions - C₃ Plants vs C₄ Plants

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