Summary
Light intensity, carbon dioxide concentration and temperature can each limit the rate at any time.
In depth
Blackman's law: rate is limited by the factor in shortest supply. Light intensity limits at low light, CO2 at high light, and temperature affects enzymes (optimum 25 to 35 °C). Greenhouses may add heat, light and CO2.
On a graph, rate rises linearly with light, then plateaus when another factor limits. Raising the limiting factor alone raises the rate. Temperature has a bell-shaped effect because enzymes denature.
Key idea: in a greenhouse, light, CO2 and temperature can be tuned for maximum growth.
Light, carbon dioxide and temperature are the main factors, with water and minerals indirectly. Light response curves rise linearly then plateau at saturation. At about 0.04 percent CO2 in air, carbon dioxide often limits at high light. Temperature affects enzymes, so rate drops above about 35 to 40 degrees for many C3 plants. Glasshouses supply extra CO2, warmth and light to raise yields.
Graphs are interpreted by finding the factor that limits at each stage: if raising light no longer increases the rate, another factor limits. Interaction is shown by plotting curves at different CO2 levels. Photoinhibition can occur at very high light, damaging PSII.
Common mistake: assuming that temperature always speeds up photosynthesis; beyond the optimum enzymes denature.
Frequently asked questions
What is Limiting Factors of Photosynthesis?
Light intensity, carbon dioxide concentration and temperature can each limit the rate at any time.
Which area of biology covers Limiting Factors of Photosynthesis, and how advanced is it?
Limiting Factors of Photosynthesis is one of the 56 topics in Plant Biology. It is rated Intermediate, so it suits learners who already know the core vocabulary. Related topics in this area include C4 Photosynthesis, Photosynthesis Efficiency Engineering, Photosynthesis.
Can you give an example of Limiting Factors of Photosynthesis?
Graphs plateau when another factor becomes limiting.
What should I learn before Limiting Factors of Photosynthesis?
Work through the Beginner topics in Plant Biology first, such as Plant Kingdom, Photosynthesis, Chlorophyll, then return to Limiting Factors of Photosynthesis. Intermediate topics assume the Beginner vocabulary.
What topics are related to Limiting Factors of Photosynthesis?
The closest topics to Limiting Factors of Photosynthesis are C4 Photosynthesis, Photosynthesis Efficiency Engineering, Photosynthesis, Photorespiration. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand Limiting Factors of Photosynthesis?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Limiting Factors of Photosynthesis. To practise the whole of Plant Biology, use the Plant Biology quiz.
How is Limiting Factors of Photosynthesis different from C4 Photosynthesis?
Limiting Factors of Photosynthesis: Light intensity, carbon dioxide concentration and temperature can each limit the rate at any time. C4 Photosynthesis: A pathway that concentrates CO2 in bundle sheath cells to reduce photorespiration in hot climates, as in maize. Read both side by side and note what each one explains.
What is a common mistake about Limiting Factors of Photosynthesis?
Assuming that temperature always speeds up photosynthesis; beyond the optimum enzymes denature.
How should I study Limiting Factors of Photosynthesis step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with C4 Photosynthesis and explain the difference aloud. Finally, take the Plant Biology quiz and come back to this page for any question you miss.