How do C3 plants deal with photorespiration?
They don’t really and have to cope with areduced rate of photosunthesis. The conditions that result in photorespiration are in today’s world found in two particular conditions** — hot, arid climates and in climates that may not be that arid, but have a very high degree of solar radiation. Both of these situations are causally linked to leaf airspaces with especially low levels of CO2 (in comparison with plants living in cooler, more mesic climates). The “desert” plants have the problem of needing to keep their stomata closed during the day to prevent excessive water loss. The CO2 levels inside the leaf are driven downward by photosynthesis and with closed stomata, gas exchange with the ambient air is effectively turned off. This is how we end up with the especially low levels of CO2 that put the plant in a position where photorespiration might occur. Plants living in areas where intense solar radiation would “kick up” the rate of photosynthesis to extremely high levels may reach the p
