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Cd鈴井 伸郎; 中村 進一*; 伊藤 小百合; 河地 有木; 石岡 典子; 藤巻 秀
no journal, ,
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.
Cd and 
Cd伊藤 小百合; 鈴井 伸郎; 河地 有木; 石岡 典子; 藤巻 秀
no journal, ,
In this study, it was characterized that the mechanism of Cd transport in soybean plants using mixed tracer, which included Cd (half-life: 6.5 hr) and Cd (half-life: 453 d). We described the dynamics of Cd transport in the test plants using the positron-emitting tracer imaging system (PETIS). The Cd was used in the experiments with autoradiography and NaI 
-ray detector to study Cd distribution within the same plant individuals. Soybean plants at beginning seed stages were subjected to the experiments. Cd tracer (including Cd and Cd) was added to the culture solution with 0.1 
M non-radioactive Cd. The imaging was performed for 36 hours. The plants were sampled at about 2, 3 and 5 days after the point of Cd feeding. In the field of view of PETIS, Cd appeared in the shoot base about a few hours after Cd feeding and moved upward through the stems. With the autoradiography, weak signal was detected in the seeds and pods at 2 days after Cd feeding, while no signal was detected in the leaves. It indicates that Cd is transferred to the pods and seeds without passing through leaves by this moment. Results with NaI -ray detector revealed that a part of Cd absorbed by the roots moved and accumulated into the seeds, pods, leaves and petioles gradually within 5 days.
中村 進一*; 鈴井 伸郎; 長坂 俊紀*; 伊藤 小百合; 河地 有木; 石岡 典子; 服部 浩之*; 茅野 充男*; 藤巻 秀
no journal, ,
In our previous work, responses of GSH in sieve tubes to Cd treatment were investigated. These results suggested that GSH might be playing important roles in controlling Cd movement in plants. In this work, effects of GSH to Cd transport and accumulation were investigated when GSH was administered to specific organs. Plants were grown hydroponically in a green house and were treated with Cd and GSH. After 2D treatment, Cd content in their shoots and roots were measured. We employed PETIS (Position Emitting Tracer Imaging System) to visualize Cd movement in plants and analyzed the dynamics with the obtained image data. Cd content in the shoots was drastically reduced when their roots were treated with GSH. However, Cd content in the shoots increased slightly when sink-leaves were treated with GSH. Reduction of Cd transport and accumulation by GSH, administered to roots, was also confirmed by serial images of Cd movement, obtained by PETIS. Our results demonstrated that effects of GSH to Cd transport and accumulation in the plants were different in the organs where GSH was administered.