Question

High temperatures increase reaction rates but lower rubisco selectivity for co2 versus o2. high leaf temperatures thus:

Answer 1

High temperatures increase reaction rates but lower rubisco selectivity for carbon dioxide versus oxygen. High leave temperature thus INCREASE PHOTORESPIRATION RATES.
Photorespiration rates is the rate at which a plant take up oxygen in the light and give out some carbon dioxide. It is a wasteful pathway which lead to the wasting of some of the energy produced by photosynthesis.