Question

Name any four external factors which influence the process of photosynthesis.

Answer 1

Factors affecting the rate of photosynthesis:

1. Plants can synthesize their food with the help of chlorophyll found on leaves in the presence of sunlight by the process of photosynthesis.
2. The rate at which photosynthesis takes place is affected by many factors such as light, carbon dioxide, water, and temperatures.
3. Effect of light:
   • Photosynthesis cannot take place without the presence of sunlight.
   • The rate of photosynthesis initially increases with a steady increase in the light intensity to an optimum rate and then it becomes constant.
   • The high light intensity can damage the chlorophyll and therefore reduce the rate of photosynthesis.
4. Effect of CO₂:
   • The rate of photosynthesis increases with the increase in the amount of carbon dioxide in the atmosphere.
   • If the concentration of carbon dioxide is exceeded above an optimum level it will reduce the rate o photosynthesis.
5. Effect of H₂O:
   • The amount of water decides the rate of photosynthesis.
   • If the amount of water decreases in the soil then the rate of photosynthesis is adversely affected.
6. Effect of temperature:
   • When the temperature increases gradually to a certain level the rate of photosynthesis also increases.
   • But at a higher temperature, the enzymes regulating various pathways may cease to exist which will lead to a reduced rate of photosynthesis.
   • At low temperatures, the rate of photosynthesis decreases because enzymes cannot function.