Abstract
The Positron Emitting Tracer Imaging System (PETIS) is a non-invasive tool to capture a serial image of distribution of positron-emitting radioactive tracers in an intact plant body. This technique has been employed in studies of transportation of nutrients in living plants. In this study, we focused on cadmium which contamination of crops is one of the most important problems in the world.
107Cd (half-life: 6.5 hours) was prepared as the radiotracer, with ion beam bombardment and chemical purification. The tracer was fed to four-week-old rice plants from hydroponic culture, and PETIS imaging of aerial part of the plants was performed for 36 hours. A serial image of cadmium transport was obtained, and time-activity curves in some regions of interest were extracted from the data. We analyzed the time-activity curves using kinetic modeling and successfully estimated physiological parameters, e.g. transit times of cadmium transport from the culture to the aerial portion.
