Date of Birth


Research Fields, Keywords

Plant science, Environmental science, Research Ethics

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Degree 【 display / non-display

  • Doctor (Bioscience)  Nara Institute of Science and Technology  2001.03

Campus Career 【 display / non-display

  • University of Shiga Prefecture  School of Environmental Science  Department of Biological Resources Management  Professor   2019.04 - Now

  • University of Shiga Prefecture  School of Environmental Science  Department of Biological Resources Management  Associate Professor   2010.10 - 2019.03


Papers 【 display / non-display

  • Comparison of radioactive and stable cesium uptake in aquatic macrophytes affected by the Fukushima Dai-ichi Nuclear Power Plant accident

    Yoshiyasu Nagakawa, Michihisa Uemoto, Takahide Kurosawa, Kohtaroh Shutoh, Hiroshi Hasegawa, Noboru Sakurai & Emiko Harada

     Journal of Radioanalytical and Nuclear Chemistry  319   185 - 196  2018.12

    10.1007/s10967-018-6304-4  Joint Work  Joint(The vice charge)

  • Mn accumulation in a submerged plant Egeria densa (Hydrocharitaceae) is mediated by epiphytic bacteria

    Tsuji K., Asayama T., Shiraki N., Inoue S., Okuda E., Hayashi C., Nishida K., Hasegawa H., Harada E.

    Plant Cell and Environment  Plant Cell and Environment  40 (7)   1163 - 1173  2017.07

    10.1111/pce.12910  Joint Work  


    © 2017 John Wiley & Sons Ltd Many aquatic plants act as biosorbents, removing and recovering metals from the environment. To assess the biosorbent activity of Egeria densa, a submerged freshwater macrophyte, plants were collected monthly from a circular drainage area in Lake Biwa basin and the Mn concentrations of the plants were analysed. Mn concentrations in these plants were generally above those of terrestrial hyperaccumulators, and were markedly higher in spring and summer than in autumn. Mn concentrations were much lower in plants incubated in hydroponic medium at various pH levels with and without Mn supplementation than in field-collected plants. The precipitation of Mn oxides on the leaves was determined by variable pressure scanning electron microscopy-energy dispersive X-ray analysis and Leucoberbelin blue staining. Several strains of epiphytic bacteria were isolated from the field-collected E. densa plants, with many of these strains, including those of the genera Acidovorax, Comamonas, Pseudomonas and Rhizobium, found to have Mn-oxidizing activity. High Mn concentrations in E. densa were mediated by the production of biogenic Mn oxide in biofilms on leaf surfaces. These findings provide new insights into plant epidermal bacterial flora that affect metal accumulation in plants and suggest that these aquatic plants may have use in Mn phytomining.

  • Mn accumulation in a submerged plant Egeria densa (Hydrocharitaceae) is mediated by epiphytic bacteria.

    Tsuji K, Asayama T, Shiraki N, Inoue S, Okuda E, Hayashi C, Nishida K, Hasegawa H, Harada E.

     Plant, Cell and Environment  40   1163 - 1173  2017.05

    Joint Work  Joint(The main charge)

  • Synchrotron radiation X-Ray analysis of metal-accumulating plants

    Hokura A., Harada E.

    Metallomics: Recent Analytical Techniques and Applications  Metallomics: Recent Analytical Techniques and Applications   125 - 145  2017.01

    10.1007/978-4-431-56463-8_6  Joint Work  


    © Springer Japan KK 2017. X-ray microanalyses have been utilized to determine mechanisms of metal detoxification and homeostasis in plants and are powerful tools, especially for target plants unsuitable for genetic analyses. This chapter describes several synchrotron-based research methods to determine metal element distribution and speciation of metal-accumulating plants. The procedures are described, to show how micro-X-ray techniques are applicable to various biological materials, including those that are solid or liquid, soft or hard, or wet or dry. Combination of X-ray microanalysis with other methodologies, including TEM (transmission electron microscope), SEM (scanning electron microscope), and techniques of biochemistry and molecular biology, is described. Overall, this chapter attempts to encourage cross-disciplinary work in metallomics.

  • Zinc accumulation and vegetation ecology in the allotetraploid, Arabidopsis kamchatica ssp. kawasakiana.

    Kosugi A, Nishizawa C, Kawabe A, Harada E.

    Japanese Society for Plant Cell and Molecular Biology  Plant Biotechnology  33 (1)   33 - 37  2016

    10.5511/plantbiotechnology.15.1214a  Joint Work  Joint(The main charge)

  • Accumulation and distribution of cesium in Egeria densa, a submerged plant.

    Harada E., Nagakawa Y., Hokura A.

     SPring-8 /SACLA Research Frontiers  2015   96 - 97  2016

    Joint Work  Joint(The main charge)

  • Arabidopsis halleri ssp. gemmifera and its relatives as a model of metal accumulating plants.

    Kosugi A, Harada E.

     Journal of Crop Research  60   1 - 12  2015

    Single Work  

  • Metal accumulation by Arabidopsis halleri subsp. gemmifera at a limestone mining site.

    Kosugi A,Tamaru J, Gotou K, Furihata HY, Shimizu A, Kawabe A, Harada E.

    CSIRO  Australian Journal of Botany  63 (2)   134 - 140  2015

    10.1071/BT14242  Joint Work  


    Arabidopsis halleri subsp. gemmifera, a close wild relative of A. thaliana in eastern Asia, is an important model species of Brassicaceae used to study cadmium (Cd) and zinc (Zn) tolerance and hyperaccumulation in plants. To investigate the effects of soil factors on metal accumulation in this plant, we collected plants and rhizosphere soil samples from a limestone mining site on Mount Ibuki, and compared them with those collected from non-calcareous soil in Japan. Irrespective of the sampling site, all the plants efficiently accumulated Cd in shoot tissues. The plants growing on non-calcareous soil also accumulated Zn in shoot tissues, but shoot Zn concentration in plants growing on calcareous soils was below the level required for hyperaccumulators. The pH of calcareous soil samples was between 7.68 and 8.21. Total Zn contents were similar in calcareous and non-calcareous soils, but the amounts of Zn extractable by 0.1M HCl were lower in calcareous than in non-calcareous soil. These results indicate that the properties of calcareous soil affect metal accumulation in plants.

  • Radiocesium accumulation in Egeria densa, a submerged plant-possible mechanism of cesium absorption

    Kowata H., Nagakawa Y., Sakurai N., Hokura A., Terada Y., Hasegawa H., Harada E.

    Journal of Analytical Atomic Spectrometry  Journal of Analytical Atomic Spectrometry  29 (5)   868 - 874  2014.01

    10.1039/c3ja50346a  Joint Work  


    Radioactive cesium (Cs) was discharged into the environment in the northeast region of Japan after destruction of the nuclear power station in March 2011. In this work, we study the uptake and accumulation of Cs in a freshly submerged vascular plant, Egeria densa (Brazilian waterweed, Hydrocharitaceae), to investigate the behavior of Cs in the aquatic ecosystem and to predict the movement of the radionuclide to remove this Cs from the environment. We collected plants, waters, and sediments that had been contaminated by radioactive fallout in Fukushima Prefecture in September 2012. The activities of 134Cs, 137Cs, and 40K were measured using a germanium semiconductor detector. We found that the endogenous radioactive Cs concentrations in plants were correlated with those in the sediments. To discuss the uptake mechanism of Cs, stable 133Cs was applied separately to shoots and roots in a two-compartment bath. The results showed that the environmental Cs transferred to both shoot and root parts in plants. To analyze the detailed localization of Cs in plants, synchrotron radiation-based micro X-ray fluorescence (SR-μ-XRF) analysis was performed for the plants cultivated in a hydroponic medium containing 133Cs. The two-dimensional metal distribution of leaves was determined by μ-XRF with approximately 0.7 μm X-ray beams. The distribution showed the predominant localization of Cs, K as well as several divalent metals in the cell wall or apoplastic regions, suggesting the possible absorption mechanism of Cs in the plants. We concluded that E. densa plays an important role in the deposition of radioactive Cs in fresh water. © 2014 The Partner Organisations.

  • Assessment of willow (Salix sp.) as a woody heavy metal accumulator: Field survey and in vivo X-ray analyses

    Harada E., Hokura A., Nakai I., Terada Y., Baba K., Yazaki K., Shiono M., Mizuno N., Mizuno T.

    Metallomics  Metallomics  3 (12)   1340 - 1346  2011.12

    10.1039/c1mt00102g  Joint Work  


    Trees that accumulate metals are important plants for restoring contaminated soil because of their high biomass. In our previous study, we discovered that Salix miyabeana has the capability to take up high levels of Cd, and identified the several accumulation sites of the endogenous metals in the leaf parts of plants. To analyze the detailed localization of Cd in apoplastic and symplastic compartments in S. miyabeana, synchrotron radiation-based micro X-ray fluorescence (SR-μ-XRF) analysis and micro X-ray absorption near edge structure (μ-XANES) measurements were performed on beam line 37XU of the SPring-8 (Hyogo, Japan). The two-dimensional metal distribution of segments of young stems was obtained by μ-XRF with approximately 2 μm 2 X-ray beams and showed the predominant localization of Cd in the apoplastic region. μ-XANES analyses suggest that the apoplastic detoxification of Cd in willow depends on Cd-oxygen, but not on Cd-sulfur, interaction. S. miyabeana growing near an old mining site in Japan was then examined to evaluate the metal accumulating ability of this plant in the field. The metal concentration in the leaves of the plants was compared to that in the soil and enrichment factors (EFs) were calculated for Cu, Zn, Cd and Pb. Results showed efficient removal of Cd and Zn from the contaminated sites by the willow plants. In order to discuss the combined and long-term effect of multiple heavy metals on S. miyabeana grown in soil, variable-pressure scanning electron microscopy fitted with energy dispersive X-ray analysis (VPSEM-EDX) and SR-μ-XRF was used to characterize the serration of leaves. The combination of 2D elemental images revealed metal accumulation in the tip cells in serrations without any exudation of heavy metals from the hydathodes. © 2011 The Royal Society of Chemistry.

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Books 【 display / non-display

  • Synchrotron radiation X-ray analysis of metal accumulating plants.

    Hokura A., Harada E.

    Springer Japan  21p  2017

    Scholarly Book  Joint Work

Conferences 【 display / non-display

  • Establishment of remote training course on cultivation

    4th UST-USP Symposium  2021.03