Question

Certain plants growing in tropical region suffer from photorespiratory loss. How do they overcome it? Mention the anatomical adaptation. Mention the first stable CO₂ fixation product and the enzyme responsible for it.

Answer 1

Plants like sugarcane, maize shows C₄ pathway for the CO₂ fixation during the photosynthesis to overcome the problem of photorespiration which is energy consuming process. These plants have kranz anatomy. In kranz anatomy, the mesophyll is undifferentiated and its cells occur in concentric layers around vascular bundles. Vascular bundles are surrounded by large sized bundle sheath cells. The choloroplast of mesophyll cells are smaller and perform light reaction of photosynthesis and also possess PEPcase for the CO₂ fixation. 

The first stable product of C₄ pathway is oxalo-acetic acid. 

The enzyme responsible for the fixation of atmospheric CO₂ is PEP Carboxylase (Phosphoenol Pyruvate Carboxylase).