When several factors influence the rate of reaction, the factor that is least favourable will determine the rate at which a reaction can proceed. This is the law of limiting factors - the factor that is most unfavourable is the limiting factor.
Limiting Factors in Photosynthesis
- Light intensity
- Concentration of carbon dioxide outside the plant
- Temperature (this affects the activity of enzymes catalysing the light - independent reactions and also the rate of diffusion of carbon dioxide)
- Degree to which stomata are open or closed
- Water supply (influences stomatal aperture)
- Structure of the leaf
- Availability of chlorophyll, carrier molecules and enzymes.
When the light intensity is varied and all other factors remain constant, the rate of photosynthesis increases linearly with increased light intensity over a range of low intensities. The light intensity is the limiting factor. At high light intensities, increasing the intensity has little or no effect. A factor other than light intensity is limiting the rate of reaction: perhaps the available carbon dioxide.
As with increasing the light intensity, increasing the…