Abstract
Using the real-time radioisotope imaging system (RRIS), we present the carbon dioxide gas fixation process of a soybean plant applying the (14)C-labeled gas. When (14)CO(2) gas was supplied to the selected mature leaf, the fixed carbon, photosynthate, was transferred and accumulated to the younger leaves preferentially within 24 h. When (14)CO(2) gas was supplied to the younger leaves, fixed carbon was hardly moved. In the case of the pods, fixed (14)CO(2) gas in the leaf was preferentially transferred to the closest pod.