Interacting factors in limiting the rate of photosynthesis – Higher

If we look in more detail at the law of limiting factors, for instance, for the relationship between light intensity and the rate of photosynthesis:

Graph demonstrating the relationship between light intensity and the rate of photosynthesis

Or for carbon dioxide concentration:

Graph demonstrating how several factors may work to limit photosynthesis

With the law of limiting factors, each factor does not work in isolation. Several factors may interact, and it may be any one of them that is limiting photosynthesis.

One example of how factors might interact:

The graph shows how carbon dioxide concentration and temperature interact with the effect of light intensity on photosynthesis:

  • the rate of photosynthesis increases until factors becoming limiting
  • if carbon dioxide concentration is increased, the rate increases further, and then another factor becomes limiting
  • the rate can be increased further if the temperature is increased
  • the rate increases again until another factor becomes limiting
Graph showing how carbon dioxide concentration and temperature interact with the effect of light intensity on photosynthesis

This graph shows the effect of temperature as a limiting factor at two different carbon dioxide concentrations:

Graph showing the effect of temperature as a limiting factor at two different carbon dioxide concentrations of carbon dioxide