The Production of N-labeled nitrogen gas for imaging of nitrogen fixation by soybean nodule

Ishii, Satomi; Suzui, Nobuo; Ishioka, Noriko; Kawachi, Naoki; Matsuhashi, Shimpei; Otake, Norikuni*; Oyama, Takuji*; Fujimaki, Shu

The nodule is a symbiotic organ of leguminous plants with rhizobium. Soybean plants utilize nitrogen (N) fixed by nodules from atmospheric N. Until now, N, a stable isotope, has long been used for kinetics of N fixation and dynamics of transport of fixed N. However, because this method is invasive, it has been difficult to analyze an instant response to an environmental (ex. temperature, light conditions) change with these methods because they are invasive. We are planning to image and analyze such kinetics and dynamics quantitatively and noninvasively by using nitrogen gas labeled with N (half life: 10 min), a positron emitting isotope, and PETIS (positron imaging tracer imaging system). In this paper, we report the synthesis and purification of N-labeled nitrogen gas (N).