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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：17 パーセンタイル：51.36(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：27 パーセンタイル：65.90(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.
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.
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.
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.
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：19 パーセンタイル：78.40(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.
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.
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).
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.
河地 有木; 小柳 淳*; 鈴井 伸郎; 石井 里美; 尹 永根; 山崎 治明; 島田 浩章*; 藤巻 秀
no journal, ,
光合成によって、葉で空気中の二酸化炭素から合成された炭素栄養は、根や果実といったシンク器官へと転流される。この炭素動態を解析することで、従来困難であった光合成機能の定量的な評価が可能であると示唆されてきた。そこで本研究では、ポジトロンイメージング技術を用いて、モデル植物であるシロイヌナズナ複数個体の体内の炭素の動きを、生育環境を妨害することなく同時に撮像し、光合成機能を定量することを目的とした。植物の成長に伴う光合成機能の個体差を抑え、またそれを統計的に処理するため、同一シャーレ内で栽培した18個体の幼少期シロイヌナズナを供試植物とした。空気とトレーサガスの流出入を制御できる密閉容器を用いてC-11標識二酸化炭素を均一に投与する工夫を施した。ポジトロンイメージング技術を用いて、植物体内を移動する炭素の動きを1時間撮像し、得られた画像データを用いて数理的な解析を行った。光合成機能に差があると推察される生育段階の異なる2つのシロイヌナズナの集団の炭素固定量と転流率を定量解析した結果、ともに生育段階が進んだ個体の方が向上していることがわかった。さらに、炭素固定量は葉身の新鮮重に比例して増加しており、この妥当な結果から本手法による高い信頼性を示すことができた。多数の幼少期シロイヌナズナの炭素固定と転流を同時に定量評価できる、ポジトロンイメージング技術を用いた手法の開発に成功した。
施用効果の評価; ポジトロンイメージング技術を用いた炭素栄養の動態解析鈴井 伸郎; 山崎 治明*; 尹 永根; 河地 有木; 石井 里美; 島田 浩章*; 藤巻 秀
no journal, ,
炭素栄養の転流率の増加は果実収量の向上に直結するため、温室や植物工場などの閉鎖環境におけるトマト栽培では、転流率を増加させるための様々な条件検討がなされている。特にCO施用濃度の最適化は転流率の増加に最も効果的であると言えるが、CO濃度に対する転流率の応答を正確に評価することは技術的に困難であった。そこで本研究では、炭素11(半減期:20分)で標識したCO(CO)とポジトロンイメージング技術を用いて、トマトの同一個体における異なるCO濃度での炭素動態をそれぞれ可視化し、CO濃度の上昇に対する炭素の固定量と転流率の応答を解析した。まず、異なるCO濃度の環境下でトマト(Micro-Tom)にCOをパルス投与する実験システムを開発した。本実験システムを用いて、400, 1,500, 3,000ppmのCO濃度の環境に曝されたトマトにおけるC-光合成産物の動態画像を取得した。3段階のCO濃度の環境に曝された6個体のトマトにおける動態画像を解析したところ、炭素固定量はCO濃度の上昇と共に単調に増加していたが、果実への炭素移行量は1,500ppmで飽和に達していた。果実への転流率(移行量/固定量)については、個体間で大きなばらつきが見られたものの、CO濃度の上昇に伴って減少する傾向が認められた。
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; 鈴井 伸郎; 石井 里美; 尹 永根; 山崎 治明; 藤巻 秀
no journal, ,
分子イメージングを基盤とする可視化技術は、とりわけ植物栄養学においても大きなアドバンテージをもたらすとわれわれは考え、栄養や環境汚染物質といった植物体内物質の可視化技術の開発を行ってきた。いわゆる、この植物分子イメージング研究とは、多様な生育条件や遺伝的条件に対する元素動態の応答のイメージングによる、輸送メカニズムの解明や最適な栽培条件の探求にある。ここで植物研究におけるイメージング技術の特長は、非接触性と厳密な撮像環境の構築となる。接触による植物個体へのストレスは元素動態に大きな変化をもたらし、温度・湿度・光量等も実験対象植物内の元素動態を大きく左右することをわれわれは明らかにしてきた。これら環境条件を完全に制御し、研究対象の条件のみを変化させることができるイメージング実験環境の構築こそが、植物分子イメージング研究を成立させる必須条件だという結論に至った。
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
no journal, ,
「福島第一原発事故」により、広範囲の農地が放射性物質(おもにCs-134, Cs-137)で汚染された。これに対し、植物が土壌から物質を吸収し、地上部に送って蓄積する能力を利用した「ファイトレメディエーション」技術が注目されている。その効果は植物種,土壌条件や栽培条件に強く依存するため、最適な浄化条件の解明が強く求められている。反面、低汚染地域あるいは除染が行われた後の地域ではセシウム低吸収の作物品種や作られた農産物の安全評価技術が強く求められている。これらに対し、RIイメージング研究グループで開発を行っている、放射性セシウムのイメージング技術は複雑なパラメータを一括して解析できる最適なツールである。ここで本研究では、土壌・植物中の放射性セシウムの挙動を示すかを系統的に解明することを目的とし、土壌,植物根系から地上部への放射性セシウムの分布と移行を連続的に捉える計測技術の開発を行う。
小柳 淳*; 河地 有木; 鈴井 伸郎; 石井 里美; 尹 永根; 山崎 治明*; 島田 浩章*; 藤巻 秀
no journal, ,
ポジトロンイメージング技術を用いて、塩ストレスを与え、ソース葉に障害を受けた植物の光合成機能を定量し、シンク・ソースバランスを制御する機構を解明することを試みた。ナトリウム濃度が1, 5, 10, 20mMとなるように、塩化ナトリウムを添加した栄養培地を作製し、これら栄養培地で多数の野生型シロイヌナズナを20日間栽培した。植物にC-11標識二酸化炭素を投与し、植物体内を移動する炭素の動きを連続して撮像した。得られた画像データに対して数理的な解析を行い、各植物について炭素固定速度と転流率を算出した。その結果、炭素固定速度はナトリウム濃度10, 20mMの条件において低下した。一方、転流率はナトリウム濃度10mMの条件下で最大値を示し、20mMの条件下では顕著に低い値を示した。このことより、植物の炭素固定と転流において、塩ストレスに対する異なる感受性が示唆された。
