This study investigated the dynamic of zinc (Zn) uptake and the root-to-shoot Zn-transport when supplied as ZnSO4 (aq) or Zn-EDTA (aq) in soybean seedlings using in vivo X-ray fluorescence (XRF) and X-ray absorption spectroscopy (XANES). The time-resolved X-ray fluorescence showed that plants absorbed ca. 10-fold more Zn from ZnSO4 (aq) than from Zn-EDTA (aq). However, the uptake velocity did not influence the amount of Zn in the stem. It let furthermore appear that the plants were able to reduce the absorption of Zn from Zn-EDTA (aq) earlier than ZnSO4 (aq). Thus, the entrance of Zn2+ into the roots is not necessarily accompanied by SO42-(aq). Regardless the source, the Zn distribution and its transport in the stem were spatially correlated to the bundles and cortex nearby the epidermal cells. Its chemical speciation showed that Zn is neither transported as ZnSO4(aq) nor as Zn-EDTA(aq), indicating that these compounds are retained in the roots or biotransformed on in the root-solution interface. Zn2+ was long-distance transported complexed by organic molecules such as histidine, malate, and citrate, and the proportion of ligands was affected by the concentration of Zn2+ in the stem rather than by the type of Zn source.

中文翻译：

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时间分辨活体 X 射线光谱法探测 ZnSO4 (aq) 和 Zn-EDTA (aq) 对锌的吸收及其在大豆植物 (Glycine max) 中的根到芽转运

本研究使用体内 X 射线荧光 (XRF) 和 X -射线吸收光谱（XANES）。时间分辨的 X 射线荧光表明植物吸收了大约。来自 ZnSO4 (aq) 的 Zn 是来自 Zn-EDTA (aq) 的 10 倍。然而，吸收速度不影响茎中锌的含量。此外，似乎植物能够比 ZnSO4 (aq) 更早地减少 Zn-EDTA (aq) 对 Zn 的吸收。因此，Zn2+ 进入根部并不一定伴随着 SO42-(aq)。无论来源如何，锌在茎中的分布及其运输在空间上与表皮细胞附近的束和皮层相关。其化学形态表明，Zn 既不以 ZnSO4(aq) 形式运输，也不以 Zn-EDTA(aq) 形式运输，表明这些化合物保留在根中或在根-溶液界面上进行生物转化。Zn2+与组氨酸、苹果酸、柠檬酸等有机分子络合进行长距离转运，配体比例受茎中Zn2+浓度的影响而不是受Zn源类型的影响。