Question

If the temperature is increased above 35${}^{\circ }$C

• A. Rate of decline of respiration will be earlier than of photosynthesis.
• B. Rate of decline of photosynthesis will be earlier than decline of respiration.
• C. Both decline simultaneously.
• D. Both do not show any fixed pattern.

Answer 1

The correct option is B Rate of decline of photosynthesis will be earlier than decline of respiration.

Factors that affect photosynthesis are the intensity of light, carbon dioxide concentration, and temperature.
The rate of photosynthesis is optimum at the optimum temperature ranging from 25^oC to 35^oC this is so because at temperatures around 0^oC the enzymes stop working and at very high temperatures the enzymes get denatured. Hence if the temperature is increased to more than 35^oC there will be a decline in the rate of photosynthesis due to denaturation of carbon fixing enzymes. Similarly, at very high temperatures, the rate of respiration also falls significantly. So, the correct answer is option B.