Visualization of source and sink strength in using CO and a positron-emitting tracer imaging system (PETIS)

Fujimaki, Shu; Koyanagi, Atsushi*; Kawachi, Naoki; Suzui, Nobuo; Yin, Y.-G.; Ishii, Satomi; Shimada, Hiroaki*

We developed an experimental system to evaluate photosynthetic activities of individuals using CO tracer gas and a positron-emitting tracer imaging system (PETIS). Two petri dishes each containing nine Arabidopsis plants (16 days or 20 days after sown) were placed into an airtight cabinet, and approximately 40 MBq of CO was introduced with normal air. The gas in the cabinet was flushed out after 10 minutes of contact, then the dishes were mounted on the center of field of view of the imaging system, and the dynamic image of carbon distribution in the plants was acquired for 1 hour. As a result, the rates of carbon fixation and of carbon translocation in the respective individuals were estimated through quantitative analysis of the image data. Furthermore, the source and sink strength were visualized as a pixel-by-pixel map. Our method is valuable for quantitative analysis of effects of specific genes or substances on photoassimilation and partitioning.