Factors affecting the rate of photosynthesis

• The rate of photosynthesis is measured by the volume of O2 produced or the volume of CO2 used.
• Light Intensity: As light intensity increases the rate of photosynthesis increases. More light energy = more photoionisation of chlorophyl. Light causes stomata to open making more CO2 available for photosynthesis.
• Wavelength: Chlorophyll is actually a mixture of different pigments- chlorophyll a, chlorophyll b, carotene, etc.

  On average the pigments absorb more red and blue wavelengths of light, while green is mostly reflected.
• Temperature: Enzymes of Calvin cycle denature ( RUBISCO ) stomata close limiting CO2 uptake.

  Temperature is a limiting factor. As temperature increases, the rate of photosynthesis increases due to kinetic energy/ collisions.
• CO2: more CO2 = more substrate available to combine with RUBP.