Photosynthesis: Factors Affecting the Rate

Introduction

• Photosynthesis is a fundamental chemical reaction essential for life.
• Focus on factors that affect the rate of photosynthesis.

Main Limiting Factors

1. Light Intensity

   • Provides energy to split water, enabling carbon dioxide and water to react.
   • No light, no photosynthesis.
   • Increasing light intensity boosts the rate until it reaches a maximum.
   • Plants maximize light absorption by spreading leaves and avoiding shading.
   • Shade plants can photosynthesize efficiently in dim light.

2. Carbon Dioxide Concentration

   • Essential for photosynthesis to occur at maximum rate.
   • Insufficient CO2 limits the process.

3. Temperature

   • Enzymes involved in photosynthesis are temperature-sensitive.
   • Above 40°C: Enzymes start to denature, slowing down the rate.
   • Too Cold: Enzymes move slowly, decreasing the reaction rate.
   • Different plants have different optimum temperatures for photosynthesis based on their climate.

Other Factors

• Chlorophyll Concentration: Impacts photosynthesis rate.
• Water and Pollution: Additional factors that can limit the process.

Practical Applications

• Greenhouse Farming:
  • Use of artificial lights to extend daylight and increase light intensity.
  • Increase CO2 concentration by burning paraffin lamps.
  • Temperature control to optimize growth conditions.
  • Higher yields achieved in greenhouses (e.g., tomatoes, lettuce).
• Environmental Benefit:
  • Waste CO2 from factories can be utilized in greenhouses, turning waste into a valuable resource for plants.

Conclusion

• Key limiting factors: CO2 concentration, light intensity, and temperature.
• There is a maximum rate of photosynthesis that can be achieved.