Real-time imaging of zinc uptake and translocation in an intact plant using Zn
Znを用いた植物体内における亜鉛のリアルタイムイメージング
鈴井 伸郎; 山崎 治明; 河地 有木; 石井 里美; 石岡 典子; 藤巻 秀
Suzui, Nobuo; Yamazaki, Haruaki; Kawachi, Naoki; Ishii, Satomi; Ishioka, Noriko; Fujimaki, Shu
Zinc is an essential element for plants. Real-time imaging of zinc dynamics has been a powerful tool for elucidating how plants regulate zinc uptake and translocation. In the past decade, we have employed a positron-emitting tracer imaging system (PETIS), which provides serial time-course images of the two-dimensional distribution of a radioisotope (e.g. C, N, Fe, Cu, Cd) in an intact plant without contact. Real-time imaging of zinc by PETIS has been conducted using Zn (half-life: 9.2 hours), which was produced by ourselves in the facility with a cyclotron. In this study, we demonstrate that real-time imaging of zinc is also possible using commercially available radioisotope, Zn (half-life: 244 days). The tracer solution containing Zn was fed to a rice plant and serial images of Zn distribution were successfully obtained by PETIS. Uptake kinetics (Km/V) and translocation velocity of zinc were determined from the image data. Furthermore, we observed zinc translocation for several weeks by taking advantage of the long half-life. These results indicate that Zn is widely useful for the analysis of zinc dynamics in plants.