STUDIES ON THE RE-ASSIMILATION OF RESPIRATORY CO2 IN ILLUMINATED LEAVES

Experiments were performed, using rice, barley and Hydrangealeaves, to examine the re-assimilation of respiratory ¹⁴CO₂while photosynthesis is going on in an open air flow system. It was found that the leaves which had assimilated ¹⁴CO₂ beforehandevolved, when kept under photosynthesizing conditions, threeto four tenths (variable according to plant species and externalconditions) of the amount of ¹⁴CO₂ to be produced in the dark.Such an incomplete re-utilization of ¹⁴CO₂ was observed alsoin spinach leaf homogenate as well as in the leaves which hadpreviously absorbed ¹⁴C-glucose. The ¹⁴CO₂ output in rice leaves was found to be acceleratedby the light of high intensity. A possibility of light stimulationon the respiration was suggested. (Received October 7, 1961; )