Abstract: | Leaves of the tea plant photosynthesizing in 14CO2 incorporatedmuch radioactivity into intermediates of the glycolate pathwayand little into C4 acids. Increased O2 in the atmosphere decreasedphotosynthesis, stimulated photorespiration, and increased theCO2 compensation point. In air the rate of photorespirationwas 19% of net photosynthesis. These observations indicate aC3 rather than a C4 mechanism of photosynthesis. |