Question

Name the external factors which affect 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. Although, the rate of photosynthesis can alter with the factors present in the environment.

Factors that affect the rate of photosynthesis:

Effect of light:

1. Photosynthesis cannot take place without the presence of sunlight.
2. The rate of photosynthesis initially increases with a steady increase in the light intensity to an optimum point and then it becomes constant.
3. The high light intensity can damage the chlorophyll and therefore reduce the rate of photosynthesis.

Effect of CO₂:

1. The rate of photosynthesis increases with the increase in the amount of carbon dioxide in the atmosphere.
2. If the concentration of carbon dioxide is exceeded above an optimum level it reduces the rate of photosynthesis.

Effect of H₂O:

1. The amount of water decides the rate of photosynthesis.
2. If the amount of water decreases in the soil then the rate of photosynthesis is adversely affected.

Effect of temperature:

1. When the temperature increases gradually to a certain level the rate of photosynthesis also increases.
2. But at a higher temperature, the enzymes regulating various pathways may cease to exist which will lead to a reduced rate of photosynthesis.
3. At low temperatures, the rate of photosynthesis decreases because enzymes cannot function.