Factors Affecting Photosynthesis – Class 11 | Chapter – 13 | Biology Short Notes Series PDF

Factors Affecting Photosynthesis: Photosynthesis is the process of conversion of light energy (sunlight) into chemical energy (food) by using carbon dioxide, water and chlorophyll as raw materials.

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Various Factors Affecting Photosynthesis

Light intensity

  • When temperature and carbon dioxide concentration remain constant, changes in light intensity affect the rate of photosynthesis
    • The greater the light intensity, the more energy supplied to the plant and therefore the faster the light-dependent stage of photosynthesis can occur
    • This produces more ATP and reduced NADP for the Calvin cycle (light-independent stage), which can then also occur at a greater rate
    • During this stage of the graph below, light intensity is said to be a limiting factor of photosynthesisThe rate of photosynthesis increases as light intensity increases:
  • At some point, if light intensity continues to increase, the relationship above will no longer apply and the rate of photosynthesis will reach a plateau
  • At this point, light intensity is no longer a limiting factor of photosynthesis – another factor is limiting the rate of photosynthesis
  • The factors which could be limiting the rate when the line on the graph is horizontal include temperature being too low or too high, or not enough carbon dioxide

Carbon dioxide concentration

    • Carbon dioxide is one of the raw materials required for photosynthesis
    • It is required for the light-independent stage of photosynthesis, when CO2 is combined with the five-carbon compound ribulose bisphosphate (RuBP)
    • This means the more carbon dioxide that is present, the faster this step of the Calvin cycle can occur and the faster the overall rate of photosynthesisThe rate of photosynthesis increases as carbon dioxide concentration increases:
  • This trend will continue until some other factor required for photosynthesis prevents the rate from increasing further because it is in short supply
  • The factors which could be limiting the rate when the line on the graph is horizontal include temperature being too low or too high, or not enough light

Temperature

  • As temperature increases the rate of photosynthesis increases as the reaction is controlled by enzymes
  • However, as the reaction is controlled by enzymes, this trend only continues up to a certain temperature beyond which the enzymes begin to denature and the rate of reaction decreases

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By Team Learning Mantras