A Noninvasive monitoring system of cadmium uptake by intact plants using the radioisotope Cd

多点型ポジトロン検出器を用いた植物のカドミウム吸収特性の解析

鈴井 伸郎; 中村 進一*; 伊藤 小百合; 河地 有木; 石岡 典子; 藤巻 秀

Suzui, Nobuo; Nakamura, Shinichi*; Ito, Sayuri; Kawachi, Naoki; Ishioka, Noriko; Fujimaki, Shu

we have developed a monitoring system of Cd radioactivity in tracer solution using Positron Multi-Probe System (PMPS) that enables the noninvasive measurement of the amounts of Cd uptake by an intact plant. Two-week old oilseed rape plant was placed into a plastic cylindrical container containing 30 ml of 0.5 mM CaCl solution with approximately 10 MBq of Cd. As a result, we successfully obtained the time-course change in Cd radioactivity in the tracer solution over 24 hours. The time-course data for Cd radioactivity can be fitted to an exponential decreasing curve with a plateau. This indicates that the rate of Cd uptake by the plant was proportional to the Cd remaining in the tracer solution. To date we could simultaneously monitor the uptake amounts in 4 individual oilseed plants by shielding each detector head with lead blocks. The detailed analysis of the kinetics in various experimental conditions would provide valuable information concerning the mechanism of Cd uptake in plant.