A method to quantitate photosynthetic rate constant within leaf using carbon-11-labeled carbon dioxide and positron emitting tracer imaging system

Position emitting tracer imaging system (PETIS) and carbon-11-labeled carbon dioxide (¹¹CO₂) can image photosynthesis process in plant leaf, and ¹¹C kinetics make it possible to estimate physiological function parameters in photosynthesis. With an exposure ¹¹CO₂-gas to a leaf, PETIS experiments were performed under four light conditions on a single leaf. In order to estimate the rate constants of photosynthesis parameters, time activity curves of ¹¹CO₂ gas input and leaf response were fitted to an appropriate compartmental tracer kinetic model, which applies influx and efflux for photo-assimilation and photosynthate delivery rate constants respectively. These results are reasonable response against light environment and important to discuss photosynthesis in plant physiology and agriculture