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in a greenhouse for tomato cultivation石井 里美; 山崎 治明*; 鈴井 伸郎; 尹 永根; 河地 有木; 島田 浩章*; 藤巻 秀
JAEA-Review 2015-022, JAEA Takasaki Annual Report 2014, P. 93, 2016/02
Tomato is popularly grown in environmentally controlled system such as a greenhouse for improvement of bioproduction. It is important to control the condition in the greenhouse for increasing the translocation of fixed carbon from the leaves to the growing fruits. Elevation of COconcentration is widely employed for that purpose; however, it is difficult to estimate its effect quantitatively because tomato plants have too large inter-individual variations with developing fruits. In this study, we employed a PETIS which is a live-imaging system of nutrients in plant body using short-lived radioisotopes including 
C. We also established a closed cultivation system to feed a test plant with CO at set concentrations of 400, 1,500 and 3,000 ppm and a pulse of CO.
concentration in a closed cultivation system for the improvement of bioproduction in tomato fruits山崎 治明*; 鈴井 伸郎; 尹 永根; 河地 有木; 石井 里美; 島田 浩章*; 藤巻 秀
Plant Biotechnology, 32(1), p.31 - 37, 2015/04
被引用回数：14 パーセンタイル：52.11(Biotechnology & Applied Microbiology)To maximize fruit yield of tomatoes cultivated in a controlled, closed system such as a greenhouse or a plant factory at a limited cost, it is important to raise the translocation rate of fixed carbon to fruits by tuning the cultivation conditions. Elevation of atmospheric CO concentration is a good candidate. In this study, we employed a positron-emitting tracer imaging system (PETIS), which is a live-imaging technology for plant studies, and a short-lived radioisotope C to quantitatively analyze immediate responses of carbon fixation and translocation in tomatoes in elevated CO conditions. We also developed a closed cultivation system to feed a test plant with CO at concentrations of 400, 1500 and 3000 ppm and a pulse of CO. As a result, we obtained serial images of C fixation by leaves and subsequent translocation into fruits. Carbon fixation was enhanced steadily by increasing the CO concentration, but the amount translocated into fruits saturated at 1500 ppm on average. The translocation rate had larger inter-individual variation and showed less consistent responses to external CO conditions compared with carbon fixation.
and tobacco plants吉原 利一*; 鈴井 伸郎; 石井 里美; 北崎 真由*; 山崎 治明*; 北崎 一義*; 河地 有木; 尹 永根; 七夕 小百合*; 橋田 慎之介*; et al.
Plant, Cell & Environment, 37(5), p.1086 - 1096, 2014/05
被引用回数：23 パーセンタイル：67.03(Plant Sciences)Cadmium (Cd) accumulations in a Cd hyper-accumulator fern, (
), and tobacco, 
(
), were kinetically analysed using the positron-emitting tracer imaging system under two medium conditions (basal and no-nutrient). In , maximumly 50% and 15% of the total Cd accumulated in the distal roots and the shoots under the basal condition, respectively. Interestingly, a portion of the Cd in the distal roots returned to the medium. In comparison with , a little fewer Cd accumulations in the distal roots and clearly higher Cd migration to the shoots were observed in under the basal condition (maximumly 40% and 70% of the total Cd, respectively). The no-nutrient condition down-regulated the Cd migration in both species, although the regulation was highly stricter in than in (almost no migration in and around 20% migration in ). In addition, the present work enabled to estimate physical and physiological Cd accumulation capacities in the distal roots, and demonstrated condition-dependent changes especially in . These results clearly suggested occurrences of species-/condition-specific regulations in each observed parts. It is probable that integration of these properties govern the specific Cd tolerance/accumulation in and .
尹 永根; 鈴井 伸郎; 河地 有木; 石井 里美; 山崎 治明; 小柳 淳*; 藤巻 秀
JAEA-Review 2012-046, JAEA Takasaki Annual Report 2011, P. 92, 2013/01
The root of higher plant has important role in absorb essential nutrients critical to life. On the other hand, the root evolved special abilities to uptake of nutrients from the rhizosphere environment because that is fixed in the soil. As one example, the roots secrete organic acids to surrounding of rhizosphere for solubilization of the insoluble mineral in soil and absorb directly or indirectly of the nutrition. Previously, our group has reported that imaging of cadmium (Cd) uptake from hydroponic culture solution to root for study the mechanism of mineral metabolism by using a positron-emitting tracer imaging system (PETIS) in plant. In this study, we performed the imaging of organic matter which is exudate from root to soil cultivation by using carbon-11-labeled carbon dioxide (CO) gas tracer with PETIS.
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.
Cd for direct imaging of Cd uptake from culture to root鈴井 伸郎; 河地 有木; 石井 里美; 山崎 治明; 藤巻 秀
JAEA-Review 2011-043, JAEA Takasaki Annual Report 2010, P. 95, 2012/01
In an effort to understand the mechanism of cadmium (Cd) accumulation in grains, we have conducted noninvasive imaging of Cd in intact rice plants using a positron-emitting tracer imaging system (PETIS) and Cd. Recently, we attempt to obtain the serial images of Cd in underground parts, i.e., roots and culture solutions. In this case, the dosage of Cd should be optimized because the presence of high radioactivity in the field of view (FOV) of PETIS induces the counting loss of annihilation 
-rays, resulting the underestimation of radioactivity. Thus, in this study, we determined the optimal dosage of Cd for direct imaging of Cd uptake. Cd solution was infused into a flat "phantom" container. This phantom was measured by PETIS for 24 hours while the radioactivity of Cd in FOV decayed to 1/13 of its initial value. In the Cd phantom, the counting loss was diminished after the radioactivity of Cd in FOV decayed to below 8 MBq. On the other hand, we should allow some degree of counting loss at the initial period of imaging in order to obtain the images for kinetic analyses over the longer time period. When 5% of counting loss was allowed, the optimal dosage of Cd for the purpose was determined to be 15 MBq.
山崎 治明; 鈴井 伸郎; 河地 有木; 石井 里美; 島田 浩章*; 藤巻 秀
JAEA-Review 2011-043, JAEA Takasaki Annual Report 2010, P. 98, 2012/01
Improvement in crop yield is expected by understanding "source-sink regulation system" of higher plants. In this study, we analyzed the photoassimilate distribution system to two sink organs, the root and the shoot apex, using positron-emitting tracer imaging system (PETIS) and cold-girdling technique, which is known as a method to inhibit photoassimilate translocation. CO exposure and PETIS imaging were conducted two times with the same test plant. Cold-girdling was treated only in the second run by cooling the boundary region on the stem between shoot and root. Time-activity curves were generated from the regions of the root, shoot apex and source leaf in the PETIS data. Then, three indices were analyzed; the influx rates of photoassimilate into the two sink organs, the root and the shoot apex, and the efflux rate from the source leaf. As the results, the influx rate was decreased drastically into the root. On the other hand, influx into the shoot apex hardly changed. And the efflux rate from the leaf was decreased. These results suggest that the "source supply" is adjusted so as to keep influx rate of photoassimilate into the untreated sink.
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.
C translocation using positron-emitting tracer imaging system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
Nuclear Instruments and Methods in Physics Research A, 648(Suppl.1), p.S317 - S320, 2011/08
被引用回数：17 パーセンタイル：78.75(Instruments & Instrumentation)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 articular 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). Carbon-11-labeled carbon dioxide (CO) and PETIS enable video imaging of tracer dynamics of carbon fixation, photosynthesis, and translocation. Because of a large field of view (FOV) provided by the PETIS and the sufficiently small size of soybeans (
cultive Jack) that fit in the FOV, dynamic quantitative PETIS data of gradual changing in C activity and C distribution throughout the entire intact plant body after pulse-chase CO treatment is acquired. This indicates the successful imaging of CO photoassimilate translocation from the time of infusion into leafs to that of distribution of the whole plant body; further, carbon kinetics is analyzable to understand plant physiology and nutrition.
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; 藤巻 秀
JAEA-Review 2010-065, JAEA Takasaki Annual Report 2009, P. 106, 2011/01
We have performed phantom experiments for the quarterly maintenance of the uniformity and sensitivity correction of the PETIS to assess the performance of its newly installed detector head and maintain a sufficiently high image quality for plant study. In order to quantitatively acquire the analyzable dynamic data of PETIS images, it is mandatory to begin a scheduled work for constant quality control. We prepared a flat uniform phantom containing a radioactive solution of Na-22. Newly installed PETIS No. 4 acquired for 5 min to image the phantom in this maintenance experiment. All images were corrected for detector geometry and counting rate losses. To analyze the image quality of the phantom data, we estimated the mean value, standard deviation, and the root mean square uncertainty of a selected region of interest in the images. These works on the maintenance of PETIS quality control ensure quantitative kinetic analysis and support many other plant physiological experiments of PETIS studies.
Zn鈴井 伸郎; 山崎 治明*; 河地 有木; 石井 里美; 石岡 典子; 藤巻 秀
JAEA-Review 2010-065, JAEA Takasaki Annual Report 2009, P. 105, 2011/01
Zn (half-life: 244 days) is commercially available and frequently used as a zinc tracer in plants. Zn decays with 98.6% by electron capture and 1.4% by positron emission to stable 65Cu. Because of its weak positron emission, Zn was thought to be unsuitable for positron imaging, but there has been no verification of the possibility. In this study, we examined whether positron imaging of zinc is possible using Zn and a positron-emitting tracer imaging system (PETIS). The tracer solution containing 400 kBq Zn was fed to a rice plant (
L.) and the dynamics of Zn in plant was monitored by PETIS. As a result, serial images of Zn distribution were successfully obtained every 5 minutes for 48 hours. In addition, the uptake kinetics (
m/
max) and the translocation velocity of zinc in plant were determined from the image data. These results indicate that Zn is a suitable radioisotope for noninvasive imaging by PETIS. By taking advantage of the long half-life, Zn translocation can be visualized all through the life of plants. Furthermore, the commercial availability of Zn makes it possible to conduct noninvasive imaging of zinc in facilities without cyclotron, accelerating the research of zinc dynamics in plants.
石川 覚*; 鈴井 伸郎; 伊藤 小百合*; 石井 里美; 山崎 治明*; 河地 有木; 石岡 典子; 藤巻 秀
JAEA-Review 2010-065, JAEA Takasaki Annual Report 2009, P. 102, 2011/01
In this study, we evaluated the activities on Cd translocation of a few candidate varieties and analyzed the biological mechanisms using a positron-emitting tracer imaging system (PETIS). Three common rice cultivars, Nipponbare, Koshihikari and Sasanishiki and three candidate varieties were subjected. We equally fed the hydroponic culture solution including Cd to the six test plants and obtained the serial images of the Cd distribution in the aerial parts for 36 h using PETIS. As a result, It was found that the three candidate plants accumulated Cd in their aerial parts approximately two times as common cultivars. It was also found that almost all Cd in the culture solution was absorbed by all the tested plants. Therefore, this result indicates that the difference was due to greater activities of the candidates in the process to export Cd from the root tissue to the aerial parts, but not in the process of absorption from the culture.
Cを用いた光合成産物のイメージング; ソース・シンクバランスと転流速度の解析鈴井 伸郎; 河地 有木; 石井 里美; 伊藤 小百合; 山崎 治明*; 中村 進一*; 石岡 典子; 藤巻 秀
no journal, ,
Cトレーサー及びPositron Imaging Tracer Imaging System (PETIS)を用い、人為的にソース・シンク器官の機能を阻害した植物の糖転流の速度変化を解析した。供試植物として播種後約4週間のイネ( L.)を用いた。葉に100MBqのCOを含む空気を供給し、Cで標識された糖が葉から根へと転流する過程をPETISにより撮像した。ソース・シンク器官の機能阻害処理は、ショ糖トランスポーターの阻害剤である
-chlorobenzenesulfonic acid (PCMBS)を葉面塗布及び経根投与することで行った。PCMBS処理後数時間に渡り、PETISによる撮像を行った。得られた画像データから各器官におけるCの放射能量の経時変化のグラフを作成し、Cトレーサーの到達時間を推定する解析方法を用いて、各区での糖転流の速度を算出したところ、ソース器官にPCMBS処理を行った植物の糖転流速度の低下が確認できた。
鈴井 伸郎; 河地 有木; 石井 里美; 伊藤 小百合; 山崎 治明*; 中村 進一*; 石岡 典子; 藤巻 秀
no journal, ,
高等植物は葉(ソース器官)で合成した糖を、根や生長点などの器官(シンク器官)に転流させ、個体維持に必要なエネルギー源を全身に行き渡らせている。さらに、シンク器官とソース器官との間で情報をやり取りし、糖の転流量を必要に応じてダイナミックに変化させることで、自らの生育段階や外的環境の変化に対応している。このソース-シンク器官間に存在する情報伝達の機構を明らかにするうえで、環境に応じた糖の転流量の変化を経時的かつ非侵襲的に測定することができるPositron Emitting Tracer Imaging System (PETIS)は非常に強力な研究ツールである。われわれは、PETISで得られた炭素動態の動画像データから糖の転流速度を算出するプログラムを開発した。本発表では、ダイズ()及びイネ()を供試植物として用い、ソース葉及び隣接する葉の光強度を変化させた植物の炭素動態をPETISにより撮像することで、植物個体のシンク・ソースバランスに対する糖転流速度の応答を解析した結果を報告する。
藤巻 秀; 河地 有木; 鈴井 伸郎; 石井 里美; 伊藤 小百合; 山崎 治明; 石岡 典子
no journal, ,
安全な食糧の安定供給は、言うまでもなく、人類共通の目標である。しかしながら、不良環境の増大など、今後の農業をとりまく状況は厳しい。「吸収」「同化」「移行」「蓄積」などから成る植物の物質輸送機能を人為的に制御し、利用することが農業の本質であり、これらの機能の研究は食糧生産上の諸問題の解決に対して重要な役割を担っている。われわれはこれまで10年以上に渡り、ポジトロン放出核種で標識したさまざまなトレーサを製造し、光合成産物,硝酸イオン,鉄,亜鉛,マンガンなどの栄養、またカドミウム,バナジウムなどの有害物質が生きた植物体内を移行する様子を撮像し、その挙動を解析してきた。さらに、実用的な知見を得るために「炭素固定速度」などの定量的情報を数理的解析によって動画像データから導くアルゴリズムの開発を進めてきており、環境応答に関する研究を行っている。本発表では代表的な研究例を紹介し、今後の展望について述べる。
鈴井 伸郎; 山口 充孝; 河地 有木; 山崎 治明; 石岡 典子; 藤巻 秀
no journal, ,
本発表では、「生きた植物体」における「複数元素」の吸収活性を測定するために開発した、線スペクトロメーターを用いたモニタリングシステムについて報告する。線スペクトロメーターとして高エネルギー分解能を持つCdTe半導体検出器を用い、異なる線を放出する植物栄養元素のRIトレーサーを植物体に投与し、水耕液中の線スペクトルを連続的に取得するシステムを構築した。次に播種後4週間のイネに
Cd(80kBq)及びZn(650kBq)を経根投与し、得られた線スペクトルの経時データから88keV及び1116keVのピークカウントを抽出した。その結果、イネにおけるCd及びZnの吸収量の経時変化を12時間に渡り追跡することに成功した。現在、
Mnと
Feを加えた計4核種の同時モニタリングを検討しており、「植物栄養学」の研究分野において高いインパクトを持つRIトレーサー実験系の確立を目指している。
Znを用いた植物体内における亜鉛のポジトロンイメージング鈴井 伸郎; 山崎 治明; 河地 有木; 石井 里美; 伊藤 小百合; 石岡 典子; 藤巻 秀
no journal, ,
植物体内における亜鉛の動態をポジトロンイメージング技術により可視化する際に、これまでは
Znを自ら製造して用いてきたが、娘核種のCuがポジトロン放出核種である問題があった。そこで本研究では、購入可能なRIであるZn(娘核種Cuは安定同位体)をトレーサーに用いることで、亜鉛のポジトロンイメージングが可能であるかを検証した。par400kBqのZnを含むトレーサー溶液をイネに投与し、PETISで撮像したところ、Znが根から吸収され、地上部へ輸送され、蓄積される動画像を得ることができた。さらに、異なるキャリア濃度(基質濃度)のトレーサー溶液を投与した際の動画像から、Znの吸収速度を算出し、ミカエリス・メンテン式を用いることで、イネにおける亜鉛の吸収特性(Km, Vmax)を評価することに成功した。
Cを用いた光合成産物のイメージングによる植物の節の機能解析山崎 治明; 鈴井 伸郎; 河地 有木; 石井 里美; 伊藤 小百合; 島田 浩章*; 石岡 典子; 藤巻 秀
no journal, ,
本研究では植物の節における元素分配メカニズムの解明を目的とし、まず節の機能を人為的に阻害する実験系の確立を目指した。今回、その候補として植物の一部を局所的に冷やす試みを行った。ダイズの葉柄、及びイネの茎基部に局所冷却を施し、それぞれの葉にCOを投与した。次に、植物がCOを吸収・固定し、C-光合成産物として体内を移行・蓄積する様子を、PETISを用いてそれぞれ2時間撮像した。実験終了後、得られた動画像からダイズの節及びイネの茎基部におけるC放射活性の経時変化を算出し、局所冷却を行わなかった場合と比較した。その結果、局所冷却を行ったダイズ、イネでは、ともに節でのC-光合成産物の蓄積量に減少傾向が見られた。また、ダイズではC-光合成産物の節への到達時間に遅延が認められた。これらの結果より、局所冷却によって篩管内及び節での光合成産物の移行量が減少することが明らかとなり、節の機能を阻害する手段として局所冷却が有効である可能性が示された。
Zn鈴井 伸郎; 山崎 治明; 河地 有木; 石井 里美; 石岡 典子; 藤巻 秀
no journal, ,
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.
