Question

Define photo-oxidation and photorespiration.

Answer 1

In general, an increase in light intensity will accelerate the rate of photosynthesis, provided that no other factor is limiting. Sometimes, high light intensities oxidise the chlorophyll, hence inhibits the rate of photosynthesis. This phenomenon is known as photo-oxidation. On the contrary, the process of uptake of oxygen and production of carbon dioxide in light by photosynthesizing tissue is called photorespiration. A large proportion of $C{O}_2$ assimilated by photosynthesis is lost through photorespiration.