Affecting Photosynthesis

• Plants make their own food using photosynthesis, which is important not only for the plants themselves, but for the other organisms that feed on the plants.
• Water is often the main limiting factor for photosynthesis in the UK.
• Water plays a crucial role in photosynthesis as a solvent for all the chemical reactions in cells.
• Light intensity affects the rate of photosynthesis.
• The light intensity fluctuates during the day and will also be affected by the weather.
• The rate of photosynthesis will vary with the time of day and the season in countries like the UK.
• Carbon dioxide levels in the atmosphere are rising due to greenhouse gas emissions.
• The gases responsible for global warming are carbon dioxide, methane, nitrous oxide and CFCs (chlorofluorocarbons).
• Carbon dioxide concentration is a crucial limiting factor for photosynthesis.
• Climate change is expected to negatively affect crop production as temperatures rise.
• The optimum temperature for most plants is 15°C to around 40°C.
• For shade-adapted plants, the compensation point is lower, meaning their rate of photosynthesis will exceed the rate of respiration at lower light intensities than the plants adapted to sun.
• Temperature is a significant factor in photosynthesis, with plants able to photosynthesise over a wide range of temperatures from 0°C to around 50°C.
• The position of the compensation point is different in plants grown in brighter conditions.
• Temperature affects the rate of photosynthesis in crop plants and affects where certain crops can be grown.
• The optimum and maximum temperatures for the growth of some crops are listed in the table.