Factors affecting photosynthesis

• Plants need to carry out photosynthesis to survive
• Four main factors that affect photosynthesis:

  • Light intensity
  • Temperature
  • Concentration of carbon dioxide in the air
  • Amount of chlorophyll in the plants
• Chlorophyll is the pigment within chloroplasts that absorbs light energy needed for photosynthesis
• Factors affecting chlorophyll levels in plants:

  • Different plants naturally have different amounts of chlorophyll
  • Levels can vary within an individual plant due to disease, infection with tobacco mosaic virus, environmental stress, or lack of nutrients like water
• Limiting factors for photosynthesis:

  • Light
  • Carbon dioxide
  • Temperature
• Graphs used to show the relationship between light intensity, carbon dioxide concentration, temperature, and rate of photosynthesis
• Light intensity graph:

  • As light intensity increases, the rate of photosynthesis increases
  • Plateaus when another factor becomes limiting
• Carbon dioxide graph:

  • The more carbon dioxide, the higher the rate of photosynthesis
  • Plateaus when another factor becomes limiting
• Temperature graph:

  • Rate of photosynthesis initially rises with temperature
  • Rate drops as enzymes denature, fully denatured at around 45 degrees
• Comparison of experiments:

  • Two curves on a graph show how light intensity affects photosynthesis at different temperatures
  • Higher temperature leads to a higher maximum rate of photosynthesis
• Creating optimal conditions for photosynthesis:

  • Farmers use greenhouses to increase temperature and provide artificial light
  • Pumping carbon dioxide or using heaters can increase carbon dioxide levels
  • Enclosed greenhouses protect plants from pests and pathogens
  • Fertilizers and pesticides are used to provide essential minerals and protect plants