Factors Affecting Photosynthesis - At any moment, the factor that stops the reaction going any faster is called the limiting factor. Factors that may affect the rate of photosynthesis include: - Temperature as temperature increases so does the rate, this is because more energy is provided for the reaction, as the temperature approaches 45 degrees he rate of photosynthesis drops to 0 because the enzymes controlling photosynthesis have been destroyed. -Carbon Dioxide Concentration As the concentration of CO2 increases so does the rate, this is because CO2 is needed for the reaction, after reaching a certain point an increase in CO2 has no further affect (CO2 is no longer a limiting factor). -Light Intensity As light intensity increases so does the rate, this is because there is more energy being provided, after reaching a certain point, any increase in light has no further affect, it is no longer a limiting factor. -Chlorophyll Concentration This does not vary in the short term but may change if plants are grown in soil without enough to make chlorophyll.
By looking at a graph it can be possible to say what the limiting factor is at any point. Greenhouses can be used to increase the rate of photosynthesis. By controlling lighting, temperature and carbon dioxide, farmers can increase the growth rate of their crops.
When light intensity is studied, doubling the distance between the lamp and the pondweed will reduce the light intensity by a quarter. This is called the inverse square law.