Factors that can Affect the Pathways in Photosynthesis

Factors that can Affect the Pathways in Photosynthesis

Light Intensity

  • Photosynthesis requires light energy to convert carbon dioxide and water into glucose, through a process known as light-dependent reactions.
  • Therefore, the intensity of light is a major factor affecting photosynthesis; higher light intensity generally increases the rate of photosynthesis.
  • However, beyond a certain light intensity, the rate of photosynthesis does not increase. This is because all the photosynthetic pigments present in the chloroplasts are already fully engaged in the photosynthesis process.

Carbon Dioxide Concentration

  • Carbon dioxide concentration is another significant factor, as it is one of the main components required for photosynthesis.
  • Low carbon dioxide levels can limit the rate of photosynthesis, as less carbon dioxide is available for the production of glucose.
  • Similarly to light intensity, increasing the carbon dioxide concentration beyond a certain point does not increase the photosynthesis rate as all available enzyme sites are already utilised.


  • As with most biochemical processes, temperature plays a crucial role in photosynthesis by affecting enzyme activity.
  • Within a reasonable range, increasing the temperature up to an optimum point enhances the rate of photosynthesis, as kinetic energy boosts enzyme reactions.
  • Above the optimum temperature, enzyme activity slows down because enzymes – proteins – denature and lose their ability to catalyse reactions.

Water Availability

  • Water is a key component in photosynthesis, and its availability can greatly affect photosynthetic processes.
  • Inadequate water supply can reduce the efficiency of photosynthesis and stunt plant growth.
  • Some plants have adapted to survive in dry conditions by implementing mechanisms to preserve water, such as closing stomata during the day and opening them at night.

Chlorophyll Concentration

  • Chlorophyll molecules are responsible for the absorption of light energy during photosynthesis.
  • A greater concentration of chlorophyll results in enhanced light absorption and, consequently, a higher rate of photosynthesis.
  • Lack of nutrients, particularly magnesium which is a component of chlorophyll, can limit chlorophyll production and photosynthesis.

In conclusion, several factors can affect photosynthetic pathways, including light intensity, carbon dioxide concentration, temperature, water availability, and chlorophyll concentration. Understanding these factors allows us to unlock the potential of crop yield and manage plant growth more efficiently.