photorespiration poses a threat to plants yet it occurs in angiosperms,why?
Photorespiration is a process in which there is no formation of ATP or NADPH, but there is utilization of ATP with release of CO2. It is also considered a wasteful process. It takes place by involving an interaction of three organelles – chloroplast, peroxisome and mitochondria. It is also known as photosynthetic carbon oxidation cycle. In the presence of high light and limited supply of CO2 , photorespiration has a useful role in protecting the plants from photo-oxidative damage. This means that if there is no enough CO2 available to utilize light energy for carboxylation to proceed, the excess light energy causes damage to plants. But photorespiration, that is oxygenation of RuBP, utilizes part of the light energy and saves the plant from the photo-oxidative damage. Thus, it is a wasteful process but has also useful role in plants also.