Visualization of how light changes affect ion movement in rice plants using a real-time radioisotope imaging system

Abstract

We developed a real-time radioisotope imaging system (RRIS) technique that can nondestructively visualize the element absorption and transport process in plants, using not only positron emitters but also commercially available radioisotopes. In this study, we applied RRIS to analyze light effects on ion movement in rice plants. As tracers, 28Mg, 32P, and 45Ca were used. During the first 5 h, dark/light cycle of 3/7 min were set up; the RRIS needs dark conditions during capturing. When the light was ceased 5 h after supplying each tracer, 32P transport from root to shoot decreased immediately. In contrast, 28Mg and 45Ca transport did not change with light conditions. These results suggest that the P transport is dependent on water flow, whereas Mg and Ca transport are independent of water flow.