放射光マイクロビーム蛍光X線分析とX線吸収微細構造解析を用いたイネのカドミウムの蓄積機構に関する研究  [in Japanese] Study on Accumulation Mechanism of Cadmium in Rice (Oriza sativa L.) by Micro-XRF Imaging and X-ray Absorption Fine Structure Analysis Utilizing Synchrotron Radiation  [in Japanese]

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Abstract

イネにおけるCdの蓄積機構に関する新しい知見を得ることを目的として,植物体組織を非破壊で2次元多元素同時分析が可能な放射光マイクロビーム蛍光X線(SR-μ-XRF)分析とX線吸収微細構造(XAFS)解析を応用した.その結果,Cdを添加して栽培した二品種のイネ(日本晴,密陽23号)について,茎におけるCd及び植物必須元素の蓄積部位と,各器官(根,茎,葉)に蓄積されたCd化学形態が明らかになった.定量結果から,地下部では密陽23号より日本晴のCdの濃度が高いのに対し,地上部では二品種とも同程度のCdの濃度であった.またCdは維管束に多く分布し,品種間差は見られなかった.Cdの化学形態に関しては,根ではCd-Sの形態で存在し,品種間差は見られなかった.一方,日本晴の茎では,添加期間が長くなるにつれてCd-Sの割合が1.5倍になっているのに対し,密陽23号におけるCd-Sの割合は大きく変化しなかった.また,日本晴の葉では添加期間が長くなるにつれてCd-Sの割合が減少するのに対し,密陽23号ではCd-Sの割合が増加していた.このことから,地上部へ輸送する際の化学形態の差がCdの蓄積挙動の違いに影響を与えている可能性が示唆された.

This paper reports on the distribution of Cd and essential elements in the stems of rice plants, 'Nipponbare' and 'Milyang 23', measured by synchrotron radiation micro-XRF imaging. X-ray absorption near edge structure (XANES) analysis was applied to estimate the chemical forms of Cd in the roots, stems and leaves, aiming to reveal the mechanisms of Cd transport in rice. The results show that the Cd concentration of 'Nipponbare' was found to be higher than that of 'Milyang 23' at the root, although there was no significant difference between these two cultivars at the shoot. In addition, the distribution of Cd and the essential elements inside the plant were clearly revealed by micro-XRF imaging. It was found that Cd was also localized to the bundle. The Cd K-edge XANES analysis indicated that Cd was bound to sulfur in the root for both rice plants. Furthermore, the content of Cd combining with S (Cd−S) in the stem of 'Nipponbare' became 1.5 times higher after exposing to Cd for a long time, while only a slight change in the stem of 'Milyang 23' was found. In contrast with the stem, the leaf of 'Nipponbare' contained a lower Cd−S content than that of the control after a long-term exposure, while that of 'Milyang 23' became higher. In conclusion, the difference in the chemical form of Cd at the shoots affected the different accumulation behaviors of Cd between 'Nipponbare' and 'Milyang 23'.

Journal

  • BUNSEKI KAGAKU

    BUNSEKI KAGAKU 59(6), 463-475, 2010-06-05

    The Japan Society for Analytical Chemistry

References:  36

Codes

  • NII Article ID (NAID)
    10026476316
  • NII NACSIS-CAT ID (NCID)
    AN00222633
  • Text Lang
    JPN
  • Article Type
    ART
  • ISSN
    05251931
  • NDL Article ID
    10734772
  • NDL Source Classification
    ZP4(科学技術--化学・化学工業--分析化学)
  • NDL Call No.
    Z17-9
  • Data Source
    CJP  NDL  J-STAGE 
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