記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Plant Cell and Environment  

Phosphorus (P) is an essential macronutrient for plant growth. In deciduous trees, P is remobilized from senescing leaves and stored in perennial tissues during winter for further growth. Annual internal recycling and accumulation of P are considered an important strategy to support the vigorous growth of trees. However, the pathways of seasonal re-translocation of P and the molecular mechanisms of this transport have not been clarified. Here we show the seasonal P re-translocation route visualized using real-time radioisotope imaging and the macro- and micro-autoradiography. We analysed the seasonal re-translocation P in poplar (Populus alba. L) cultivated under ‘a shortened annual cycle system’, which mimicked seasonal phenology in a laboratory. From growing to senescing season, sink tissues of 32P and/or 33P shifted from young leaves and the apex to the lower stem and roots. The radioisotope P re-translocated from a leaf was stored in phloem and xylem parenchyma cells and redistributed to new shoots after dormancy. Seasonal expression profile of phosphate transporters (PHT1, PHT5 and PHO1 family) was obtained in the same system. Our results reveal the seasonal P re-translocation routes at the organ and tissue levels and provide a foothold for elucidating its molecular mechanisms.

DOI： 10.1111/pce.14319

Web of Science

Scopus

PubMed

その他リンク： https://onlinelibrary.wiley.com/doi/full-xml/10.1111/pce.14319

記述言語：英語   出版者・発行元：日本育種学会  

Wild species in the genus Vigna are a great resource of tolerance to various stresses including salinity. We have previously screened the genetic resources of the genus Vigna and identified several accessions that have independently evolved salt tolerance. However, many aspects of such tolerance have remained unknown. Thus, we used autoradiography with radioactive sodium (22Na+) and Inductively Coupled Plasma Mass Spec-trometry (ICP-MS) to visualize and compare Na+ allocation in Vigna angularis (Willd.) Ohwi & H.Ohashi (azuki bean), Vigna nakashimae (Ohwi) Ohwi & H.Ohashi, Vigna riukiuensis (Ohwi) Ohwi & H.Ohashi, Vigna luteola (Jacq.) Benth. and Vigna marina (Burm.) Merr.. The results indicated: 1) Tolerant accessions suppress Na+ accumulation compared to azuki bean. 2) V. nakashimae and V. marina does so by accumulating higher amount of K+, whereas V. riukiuensis and V. luteola does so by other mechanisms. 3) V. luteola avoids salt-shedding by allocating excess Na+ to newly expanded leaves. As the mechanisms of the tolerant species were different, they could be piled up in a single crop via classical breeding or by genetic engineering or genome editing.

DOI： 10.1270/jsbbs.22012

Web of Science

Scopus

PubMed

CiNii Research

記述言語：日本語   出版者・発行元：Japanese Journal of Applied Physics  

Radioisotope tracer imaging is useful for studying plant physiological phenomena. In this study, we developed an autoradiography system with phosphor powder (ZnS:Ag), "Live-autoradiography", for imaging radioisotope dynamics in a living plant. This system visualizes the element migration and accumulation in intact plants continuously under a light environment. An imaging test was performed on point sources of 137Cs, with radioactivity of 10-100 kBq of being observed; this indicates satisfactory system linearity between the image intensity and the radioactivity of 137Cs. Moreover, dynamics imaging of 137Cs was performed on an intact soybean plant for four days. The serial images indicated 137Cs accumulation in the node, vein, and growing point of the plant. The developed system can be used for studying plant physiological phenomena and can be employed for the quantitative measurement of radionuclides.

DOI： 10.35848/1347-4065/ac2b50

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Scopus

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.molp.2021.02.002

PubMed

担当区分：筆頭著者,　責任著者   記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：日本植物形態学会  

<p>生きたままの植物を用いて植物体内を動く放射性トレーサーを可視化することで，刻々と変化する体内元素の動態を定量的に解析できるシステムを筆者らは構築してきた．本システムは様々な種類の放射性トレーサーの可視化が可能であり，多種多様な元素の動態を追跡できる．視野範囲に応じて二種類のシステムを開発した．広視野撮影システムは視野範囲；20 x 10 cm，解像度；ミリオーダーであり，顕微鏡撮影システムは視野範囲；600 x 600 μm，解像度；100 μmである．この二つのシステムは生きた植物を解析の対象とすることから，撮影中に植物の生育環境に変化を与え，環境変化に対する植物応答を解析することが可能である．本システムによる可視化は，植物栄養学分野のみならずバイオサイエンスの幅広い分野への適用が期待される．</p>

DOI： 10.5685/plmorphol.33.9

CiNii Research

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.3389/fpls.2020.00563

PubMed

記述言語：日本語   出版者・発行元：一般社団法人 日本土壌肥料学会  

DOI： 10.20710/dohikouen.66.0_149_1

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：公益社団法人 日本アイソトープ協会  

<p>リアルタイムRIイメージングシステム（RRIS）は放射性同位体の非破壊イメージングに用いられており，その視野範囲はシンチレータの大きさと同等である。従来のRRISにおけるシンチレータ（fiber optic plate with scintillator; FOS）は高価で扱いにも注意を要し大型化が困難であったため，RRISの視野範囲は100×200 mmに限られてきた。本研究では，5種類の低価格で大型のプラスチックシンチレータの定量範囲などを評価し，プラスチックシンチレータを導入したRRISによって大型植物中の³²P動態を解析できることを示した。</p>

DOI： 10.3769/radioisotopes.68.73

CiNii Books

掲載種別：論文集(書籍)内論文  

© The Author(s) 2019. We have developed a real-time radioisotope imaging system (RRIS) to visualize ion transport in plants, and to measure radioactivity in living plants. To know the mechanisms of ion transport in plants, the use of living plants allows us to visualize ion movement in real time. In addition, the RRIS can analyze how a change to the plant environment affects ion transport. In this chapter, we will introduce some of the applications of the RRIS. We analyzed the effect of light on cesium, potassium, magnesium, phosphate, and calcium transport in plants using the RRIS. The results show that magnesium, potassium, and calcium transport in plants were not influenced by light. On the other hand, the amount of cesium and phosphate absorption in roots decreased after light-off. Moreover, the amount of phosphate transport from root to shoot also decreased after light-off.

DOI： 10.1007/978-981-13-3218-0_19

Scopus

J-GLOBAL

掲載種別：研究論文（学術雑誌）   出版者・発行元：Springer Science and Business Media LLC  

DOI： 10.1007/s10967-018-6102-z

その他リンク： http://link.springer.com/content/pdf/10.1007/s10967-018-6102-z.pdf

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Springer Science and Business Media LLC  

Magnesium deficiency can cause starch accumulation, photosynthesis inhibition and senescence particularly in young mature leaves. This study was performed to identify the initial process leading to leaf senescence under Mg deficiency.Gene expression in the young leaf was analyzed at days 2, 4, 5 of Mg deficiency using microarray analysis, and several Fe responsive genes were identified. Therefore, the effect of lowering Fe supply on gene expression and oxidative stress under Mg deficiency was evaluated.Transcriptome analysis revealed that 7 of the 30 most upregulated genes and 11 of the 30 most downregulated genes were Fe-responsive. Particularly, the upregulation of OsFER2 and downregulation of OsMIR and OsIRO2 hinted at the induction of excess Fe stress under Mg deficiency. Both lowering of Fe concentration in Mg-free solutions and resupply of Mg without modifying Fe concentrations at day 4 rescued leaves from senescence by inhibiting oxidative stress and normalising the expression of Fe-responsive genes. Meanwhile, Fe content was equal between control, Mg-deficient and Mg-resupplied plants.Mg shortage can induce excess Fe stress, which in turn causes oxidative stress before inhibition of photosynthesis. It is proposed that Mg deficiency disrupts a mechanism for storing toxic Fe ions into the vacuole in the expanding young leaf cells.

DOI： 10.1007/s11104-018-3658-x

Web of Science

その他リンク： http://link.springer.com/content/pdf/10.1007/s11104-018-3658-x.pdf

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1007/s10967-018-6119-3

PubMed

記述言語：日本語   出版者・発行元：一般社団法人 日本土壌肥料学会  

DOI： 10.20710/dohikouen.64.0_57_1

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Springer Science and Business Media LLC  

We developed a real-time radioisotope imaging system (RRIS) technique that can nondestructively visualize the element absorption and transport process in plants, using not only positron emitters but also commercially available radioisotopes. In this study, we applied RRIS to analyze light effects on ion movement in rice plants. As tracers, Mg-28, P-32, and Ca-45 were used. During the first 5 h, dark/light cycle of 3/7 min were set up; the RRIS needs dark conditions during capturing. When the light was ceased 5 h after supplying each tracer, P-32 transport from root to shoot decreased immediately. In contrast, Mg-28 and Ca-45 transport did not change with light conditions. These results suggest that the P transport is dependent on water flow, whereas Mg and Ca transport are independent of water flow.

DOI： 10.1007/s10967-017-5193-2

Web of Science

その他リンク： http://link.springer.com/content/pdf/10.1007/s10967-017-5193-2.pdf

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1093/pcp/pcw056

PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1071/FP15245

PubMed

掲載種別：論文集(書籍)内論文  

© The Author(s) 2016. Various radioisotope imaging techniques have been used at the Graduate School of Agricultural and Life Sciences, University of Tokyo, to analyze samples containing radiocesium (137 Cs and 134 Cs). There are two types of samples: (1) environmental samples contaminated by the fallout from the Fukushima Daiichi nuclear power plant accident, which contain relatively low concentrations of radiocesium and (2) laboratory samples from tracer experiments conducted at the radioisotope institution containing relatively high concentrations of 137 Cs. The first technique used to visualize radiocesium in soil and plants was radioluminography (RLG). RLG, which makes use of an imaging plate, has a dynamic range that is large enough to detect both environmental and tracer-added samples. To quantify radiocesium distributions, the samples were frozen and sliced before contact with the imaging plate. This freezing procedure after sampling is for preventing radiocesium movement during slicing and measurement of 137 Cs distribution. After slicing, two detection methods were employed: RLG and microautoradiography (MAR). MAR is the conventional and older method for imaging radioisotopes based on the daguerreotype process. We applied this method to frozen sections and obtained 137 Cs distributions at a higher resolution than with RLG. Following this, we employed a non-destructive method for imaging 137 Cs movement in a living plant. We developed the visualization technique called real-time radioisotope imaging system and then demonstrated 137 Cs movement from soil to rice plants using a chamber containing paddy soil, water, and rice plants. Lastly, 42 K obtained by 42Ar-42 K generation enabled a comparison between the movement of 137 Cs and 42 K. The mechanism of Cs transport has been reported to have some relationship with the K transport system, so experiments using both 137 Cs and 42 K would be useful for clarifying the mechanism in more detail.

DOI： 10.1007/978-4-431-55828-6_19

Scopus

掲載種別：研究論文（学術雑誌）   出版者・発行元：Springer Science and Business Media LLC  

DOI： 10.1007/s10967-015-4233-z

その他リンク： http://link.springer.com/article/10.1007/s10967-015-4233-z/fulltext.html

J-GLOBAL

掲載種別：研究論文（学術雑誌）   出版者・発行元：Japan Radioisotope Association  

DOI： 10.3769/radioisotopes.64.169

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：SPRINGER  

The mechanisms underlying magnesium (Mg) uptake by plant roots remain to be fully elucidated. In particular, there is little information about the effects of Mg deficiency on Mg uptake activity. A Mg uptake kinetic study is essential for better understanding the Mg uptake system.We performed a Mg uptake tracer experiment in rice plants using (28) Mg.Mg uptake was mediated by high- and low-affinity transport systems. The K (m) value of the high-affinity transport system was approximately 70 mu M under Mg-deficient conditions. The Mg uptake activity was promoted by Mg deficiency, which in turn fell to the basal level after 5- min of Mg resupply. The induced uptake rate was inhibited by ionophore treatment, suggesting that an energy-dependent uptake system is enhanced by Mg deficiency.The Mg uptake changes rapidly with Mg conditions in rice, as revealed by a (28) Mg tracer experiment. This technique is expected to be applicable for Mg uptake analyses, particularly in mutants or other lines.

DOI： 10.1007/s11104-014-2197-3

Web of Science

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1088/0031-9155/59/4/837

PubMed

掲載種別：研究論文（学術雑誌）  

DOI： 10.3769/radioisotopes.63.227

J-GLOBAL

掲載種別：研究論文（学術雑誌）   出版者・発行元：Springer Science and Business Media LLC  

DOI： 10.1007/s10967-013-2462-6

その他リンク： http://link.springer.com/article/10.1007/s10967-013-2462-6/fulltext.html

掲載種別：研究論文（学術雑誌）   出版者・発行元：Springer Science and Business Media LLC  

DOI： 10.1007/s10967-012-2131-1

その他リンク： http://link.springer.com/article/10.1007/s10967-012-2131-1/fulltext.html

掲載種別：研究論文（学術雑誌）   出版者・発行元：Springer Science and Business Media LLC  

DOI： 10.1007/s10967-012-2130-2

その他リンク： http://link.springer.com/article/10.1007/s10967-012-2130-2/fulltext.html