Question

Both excess light and photorespiration present challenges to plants. How can these be overcome?

Answer 1

Question

This is true that both excess light and photorespiration process damage the plant. Light is very important factor for the process of photosynthesis but excess light could be harmful because it lead to the destruction of photosynthetic apparatus. This phenomeon of destruction of photosynthetic apparatus is known as photoinhibition. In this process, excess light cause destruction to the "PSII" that is more sensitive to the light and lead to the less electron transfer activity by PSII . This further lead to the less efficiency of the light reaction that reduced the glucose fixation in the plant. This can be overcome by PSII repair machinery present in the chloroplast of the leaf.

Photorespiration is the process that occur in C3 plants where plants start taking oxygen and releasing carbon dioxide which is reverse of process of photosynthesis and occur in the presence of high oxygen. This process overcome by the C4 plants where they maintain a high concenteration of carbon dioxide so that enzyme RuBisco bind to the CO2 and not to O2 during dark reaction of photosynthesis.