Carbon dioxide compensation concentration in relation to photorespiratory enzymes in pea (C₃) and sorghum (C₄) as influenced by stress and nitrogen

Carbon dioxide compensation concentration (CO₂CC) in relation to photorespiratory enzymes viz., glycolale oxidase (GO) and catalase at various growth stages of Pea (C₃) and Sorghum (C₄) was studied. Attempt was made to relate nitrate reductase (NR) enzyme as marker to photo-respiration. Further, these investigations include study of CO₃CC in changed environments like moisture stress and nitrogen fertilization. A positive relationship between CO₂CC and NRA in pea was observed when nitrate was given as a sole source of nitrogen. In sorghum, CO₂CC was related more to GO, whereas stress reversed these relationships.