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

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

Radiotracer imaging technologies allow us to know dynamic images of elements in living plants. In particular, a positron-emitting tracer imaging system (PETIS), which was specially designed for plant nutrition studies, has produced various imaging experiments for uptake and translocation of nutrition. In this study, we evaluated individual photosynthetic abilities of the small plant, using CO tracer gas and PETIS. An agar plate including nine Arabidopsis plants (22 days after sown) was placed into an airtight cabinet, and approximately 40 MBq of CO was introduced. The gas in the cabinet was flushed out after 10 minutes of contact, then the agar plate was mounted in the center of field of view of the imaging system, and a dynamic image of carbon distribution in the Arabidopsis plant was acquired for 1 hour. As a result, the average rate of carbon fixation in each Arabidopsis plant was estimated with only a few percent of coefficient of variance through a mathematical analysis. Furthermore, source and sink strength were successfully visualized by quantification of the increase or decrease rate of C-labeled compounds in each pixel of the dynamic image.