Limiting factors of photosynthesis

• Light intensity


  • increased light intensity, more energy
  • only certain wavelengths used
• Temperature - 25, drop at 40


  • enzymes involved may denature
  • higher temps - stomata closure to avoid water loss, prevents carbon dioxide entering the leaf
  • higher temps - damage of thylakoid membranes, reduces sites available for electron transfer
  • higher temps - membranes are damaged, enzymes released into cell, reducing rate
  • high temps - damages chlorophyll, reduced amount of pigment to absorb light
• carbon dioxide - 0.4%


  • 0.04% in the atmosphere
  • limited if stomata close with too high carbon dioxide
• Lower light intensity


  • slow production of NADPH and ATP
  • slow conversion of GP -> TP -> RuBP
  • less TP and RuBP as it is used for GP production
• Lower temperatures


  • slower enzymes
  • all slower rates
  • similar effects with higher temps
  • consider general enzyme effects
• Lower carbon dioxide concentrations


  • RuBP -> GP conversion is slow
  • RuBP concentration rises
  • GP and TP falls as they are used to make RuBP
• Water stress


  • not enough water -> stomata close to preserve water
  • less carbon dioxide, slows carbon dioxide