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C-photoassimilate flow using positron-emitting tracer imaging system鈴井 伸郎; 河地 有木; 石井 里美; 尹 永根; 岩崎 郁*; 小川 健一*; 藤巻 秀
JAEA-Review 2014-050, JAEA Takasaki Annual Report 2013, P. 105, 2015/03
In this study, we developed an analytical method to evaluate velocity of photoassimilate flow using C-tracer and the positron-emitting tracer imaging system (PETIS). CO
gas tracer was fed to the compound leaves of the soybean plant, and serial images of C distribution were obtained by PETIS. Regions of interests (ROIs) were set in the node of the first compound leaf (ROI-1) and the stem base (ROI-2). Time course of C-radioactivity (Time-Activity Curve: TAC) in each ROI was generated from the serial images. Initial slope of the rising C-radioactivity was estimated by a linear least-square method using the TAC data. The value of the intercept of approximated line to the background line (X-intercept) was defined as "C-arrival time" to the ROIs. In order to determine X-intercept with a fair criterion, we developed an analytical program. The velocities of C-photoassimilate flows of 18 individual soybean plants were estimated by the values of C-arrival time and the distance between ROI-1 and ROI-2. As a result, the average value of the velocity was 113 cm h
and the standard deviation was 20 cm h. This result indicates the newly developed method is a reliable tool for the quantitative analysis of photoassimilate flow through the phloem.
河地 有木; 小柳 淳*; 鈴井 伸郎; 石井 里美; 尹 永根; 山崎 治明; 岩崎 郁*; 小川 健一*; 藤巻 秀
JAEA-Review 2012-046, JAEA Takasaki Annual Report 2011, P. 93, 2013/01
We had employed the positron emitting tracer imaging system (PETIS) in combination with carbon-11- labeled carbon dioxide (CO) as the tracer gas. In the present study, we have developed a new method based on PETIS and CO to evaluate individual photosynthetic abilities of young seedlings planted collectively on a petri dish with agar culture medium and thus investigate the effect of genetic modification or treatment on plant biomass enhancement. We report for the first time a method based on the use of PETIS and tracer gas of CO for the quantitative and statistical evaluation of carbon fixation by small plant individuals. We plan to extend this method to the analysis of the relationship between the individual carbon fixation ability and gene expression, which is probably related to photosynthesis.
河地 有木; 鈴井 伸郎; 石井 里美; 山崎 治明; 岩崎 郁*; 小川 健一*; 藤巻 秀
JAEA-Review 2011-043, JAEA Takasaki Annual Report 2010, P. 93, 2012/01
Elucidation of carbon kinetics in a higher plant, in particular photosynthetic carbon dioxide (CO) fixation and photoassimilate translocation, is important from viewpoint of environmental reduction in the amounts of atmospheric CO and from an agricultural viewpoint of the growth and development of the plant body. Previously, we have reported that whole-plant imaging for studying the complete carbon kinetics involved in photosynthesis and subsequent photoassimilate translocation and unloading. It was achieved using a positron emitting tracer imaging system (PETIS) in combination with carbon-11-labeled carbon dioxide (CO) gas tracer. In this study, real-time carbon kinetics in leaves, roots and other organs of a soybean was analyzed by using the newly developed method.
CO)河地 有木; 鈴井 伸郎; 石井 里美; 伊藤 小百合; 石岡 典子; 山崎 治明; 岩崎 郁*; 小川 健一*; 藤巻 秀
JAEA-Review 2010-065, JAEA Takasaki Annual Report 2009, P. 101, 2011/01
Elucidation of carbon kinetics in a plant is important from viewpoint of environmental reduction in the amounts of atmospheric carbon dioxide (CO) and from an agricultural viewpoint in terms of the growth and development of the plant body. In particular photosynthetic CO fixation and photoassimilate translocation are important topics for understanding the mechanisms underlying carbon kinetics. In this study, we have developed a method to investigate the carbon kinetics by using one of the most powerful radionuclide-based imaging techniques for plant study, that is, the Positron Emitting Tracer Imaging System (PETIS) and carbon-11-labeled carbon dioxide (CO).
河地 有木; 鈴井 伸郎; 石井 里美; 山崎 治明; 岩崎 郁*; 小川 健一*; 藤巻 秀
no journal, ,
植物中の炭素動態を理解することは、植物の生長を理解することに他ならない。本発表では、炭素-11標識二酸化炭素とポジトロンイメージング技術を用いたダイズ中の炭素動態のイメージング手法の開発について発表する。この方法によって、光合成によって葉で固定された炭素が各シンク器官へと転流する様子を定量的に可視化することができる。さらに、今回は視野内に個体全体を収めた状態で撮像することを可能にするための改良を加えた。その結果、固定された標識炭素の総量が一定に保たれ、シンク・ソース間における分配の定量的な解析が可能となった。本手法を用いたフィージビリティスタディを実施し、ダイズ個体内の炭素動態画像の経時変化を元に、各器官における炭素濃度時間変化データが得られた。取得した画像データ及び炭素濃度時間変化データの解析結果から、本手法の有用性を議論する。
河地 有木; 小柳 淳*; 鈴井 伸郎; 石井 里美; 尹 永根; 岩崎 郁*; 小川 健一*; 藤巻 秀
no journal, ,
We have developed a method based on CO
tracer gas and the positron-emitting tracer imaging system (PETIS) to evaluate individual photosynthetic abilities of young plant seedlings planted collectively on a petri dish with agar medium, for analysis studies on effects of genetic modification or treatment of chemical agents on enhancing plant biomass. As a result of evaluation experiments, C-images with little variation among the plants were obtained, and the average rate of carbon fixation by wild-type plants was estimated only with approximately 6% of standard error through a mathematical analysis, which proved the good quantitative capability of this experimental system and analysis method for evaluation of a genetically homogenous line. Then, eight plants of ch1-1 mutant, which lacks chlorophyll b and has lower carbon fixation activity, were also subjected to this method together with eight wild-type plants. It was estimated that ch1-1 mutants has a carbon fixation rate approximately 52.6 
4.1% lower than that of wild-type in average. In conclusion, we realized a method of quantitative and statistical evaluation of carbon fixation for small plant individuals, by using PETIS.
藤巻 秀
no journal, ,
本講演では、RIイメージング技術を用いてこれまでに行ってきた植物研究のうち、炭素固定・転流・蓄積の画像化および定量的解析に関する研究例を挙げて、植物の生産性を高める上で光合成産物の輸送を最適化することがいかに重要であるかを解説する。さらに、今後期待される、RIイメージング技術と遺伝学的アプローチとの融合、例えば、食料などの生産性に関する植物の生理機能の向上を目指し、遺伝子工学によって当該機能を変化させ、その変化をRIイメージングによって定量的に解析する、といった展望についても議論する。
藤巻 秀
no journal, ,
RIイメージング技術を用いてこれまでに行ってきた植物研究のうち、炭素固定・転流・蓄積の画像化および定量的解析に関する研究例を挙げて、植物の生産性を高める上で光合成産物の輸送を最適化することがいかに重要であるかを解説する。特に、5年半にわたり行ってきたCREST「CO排出抑制に資する革新的技術の創出」における研究成果について重点的に発表する。
