A = (CO₂ref − CO₂sample) × Flow Rate / Leaf Area
Net photosynthesis rate (A) is measured using infrared gas analyzers (IRGA) like the LI-6800. Air of known CO₂ concentration flows over a leaf in a chamber; the CO₂ drop indicates carbon fixation. Typical rates: C3 plants 10-25 µmol CO₂/m²/s, C4 plants 20-40, CAM plants 5-15. The light response curve shows A increasing with light intensity until the light saturation point. The CO₂ compensation point is where photosynthesis equals respiration (A=0). Factors affecting rate: light intensity, CO₂ concentration, temperature, water availability, and leaf nitrogen content. Photosynthesis research is critical for crop improvement and understanding global carbon cycling.