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鈴井 伸郎; 石井 里美; 河地 有木; 伊藤 小百合; 中村 進一*; 石岡 典子; 藤巻 秀
Proceedings of 16th International Plant Nutrition Colloquium (IPNC-16) (Internet), P. 1214, 2009/04
We developed analytical methods for monitoring carbon translocation and nitrogen fixation in intact plants using short-lived radioactive tracer gases and the positron-emitting tracer imaging system (PETIS). In the analysis of carbon translocation, we fed 
C (half life: 20.4 min)-labeled radioactive carbon dioxide gas to leave blades of rice plants, and serial images of C-photoassimilate were obtained non-invasively using PETIS. In order to understand source-sink relations, we manipulated source and sink strength by treating tested rice plants with p-chlorobenzenesulfonic acid (PCMBS), an inhibitor of sucrose transporters. As a result, a decrease in the velocity after the manipulation was successfully detected. In the analysis of nitrogen fixation, we newly developed a rapid method to produce and purify 
N (half life: 10.0 min)-labeled radioactive nitrogen gas and fed the gas to the underground part of nodulated soybean plants. As a result, obvious signal of N was observed at the nodules.
藤巻 秀; 鈴井 伸郎; 石岡 典子; 河地 有木; 伊藤 小百合; 茅野 充男*; 中村 進一*
Proceedings of 16th International Plant Nutrition Colloquium (IPNC-16) (Internet), 1 Pages, 2009/04
カドミウム107トレーサの製造法を開発し、ポジトロンイメージングを用いて、栄養成長期及び生殖成長期のイネにおけるカドミウムの輸送動態を定量的に解析した。その結果、土壌から玄米に至る過程において導管から篩管への乗り換えが重要なステップであり、それが節で行われていることを推定した。
中村 進一*; 鈴井 伸郎; 石岡 典子; 河地 有木; 伊藤 小百合; 頼 泰樹*; 服部 浩之*; 茅野 充男*; 藤巻 秀
Proceedings of 16th International Plant Nutrition Colloquium (IPNC-16) (Internet), p.1181_1 - 1181_2, 2009/04
Reduction of cadmium (Cd) accumulation in farm products has become more and more important in order to produce them in a safe and sustainable manner. It is necessary to elucidate mechanisms of Cd distribution in plants. However, these mechanisms are not fully understood. The purpose of our work is to clarify these mechanisms by visualizing Cd absorption, transport and accumulation non-invasively using positron-emitting tracer imaging system (PETIS). 
Cd (half-life: 6.5 hr) was used as a positron-emitting tracer in the PETIS experiments. We succeeded to obtain serial images of cadmium distribution in oilseed rape plants (
L.). Strong Cd signals were observed in the basal region of the shoot. We also could see strong signals in the node of oilseed rape plants. Cd distribution in oilseed rape plants will be discussed quantitatively using the results from PETIS experiments.
石川 覚*; 倉俣 正人*; 阿部 匡*; 鈴井 伸郎; 伊藤 小百合; 河地 有木; 藤巻 秀
Proceedings of 16th International Plant Nutrition Colloquium (IPNC-16) (Internet), P. 1151, 2009/04
We analyzed the real-time translocation of Cd from root to shoot among 6 rice cultivars using a positron-emitting tracer imaging system (PETIS). Cd first accumulated at the basal region of the shoot within 2 h after the exposure and the signals were much stronger in high-Cd-accumulating cultivars (indica) than in low-Cd-accumulating ones (japonica). Cd accumulated increasingly at the upper portion of the shoot with time, and the signals were obviously strong in high-Cd-accumulating cultivars. These results suggest that the different ability of root-to-shoot translocation of Cd is closely related to the genotypic variation in shoot Cd accumulation in rice.
