Assertion : Under conditions of high light intensity and limited CO ₂ supply, photorespiration has a useful role in protecting the plants from photo-oxidative damage. Reason : If enough CO ₂ is not available to utilize light energy for carboxylation to proceed, the excess energy may not cause damage to plants.

Step-by-step solution

Photorespiration protects the plants from photoxidative damage by dissipating excess of excitation energy. When the CO ₂ supply is limited and under high light intensity photorespiration takes place thus protecting the plants. If enough CO ₂ is not available to utilize light energy for carboxylation to proced, the excess energy will cause photoxidative damage to the plants. The energy liberated should be used in photophosphorylation in presence of CO ₂ . If CO ₂ is less then in C ₃ plants O ₂ combines with RuBP to