The Effect of Light on the Tricarboxylic Acid Cycle in Green Leaves

摘要: Excised green leaves of mung bean ( Phaseolus aureus L. var. Mungo) were used to determine the effect light on rate endogenous respiration via tricarboxylic acid cycle. Illumination with white at an intensity 0.043 gram calories cm −2 min −1 (approximately 8600 lux) visible radiation (400-700 nm) gave a apparent photosynthesis, measured as net CO 2 uptake, 21 mg dm hr which was about 11-fold greater than dark respiration. The feeding 14 or C-labeled acids cycle in for hours established suitable method labeling mitochondrial pools intermediates. At concentration 0.1 mm 3-(3,4-dichlorophenyl)-1,1-dimethylurea, photosynthesis inhibited 82%, and refixation derived internally from largely prevented. In presence this inhibitor respiration, evolution, continued comparable that dark. Consequently, under these conditions light-induced nonphotosynthetic processes have no significant Inhibitors cycle, malonate fluoroacetate, relative rates carbon flux through by measuring accumulation C either succinate citrate. Results interpreted indicate functions similar except brief initial inhibition transition light. Evidence obtained dehydrogenase well aconitase, fluoroacetate.