Sugiura Yuki, Kanasashi Tsutomu, Ogata Yoshimune, Ozawa Hajime, Takenaka Chisato
Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Aichi 464-8601, Japan.
Graduate School of Medicine, Nagoya University, Nagoya, Aichi 461-8673, Japan.
J Environ Radioact. 2016 Jan;151 Pt 1:250-257. doi: 10.1016/j.jenvrad.2015.10.021. Epub 2015 Nov 1.
Through the assessments of radioactive contamination after the Fukushima Dai-ichi Nuclear Power Plant (F1NPP) accident, it has been reported that some sprouts of Chengiopanax sciadophylloides (Franch. et Sav.) at the site contained radiocesium (((134),)(137)Cs) at higher concentrations than the other plants. To assess the phytoremediation properties of C. sciadophylloides for (137)Cs decontamination, we aimed to quantify the (137)Cs accumulation in C. sciadophylloides. We measured the (137)Cs concentrations in various organs of C. sciadophylloides collected from the forest in the town of Kawamata, Fukushima prefecture, together with the concentrations of other elements [potassium (K), rubidium, (133)Cs, calcium, strontium, and manganese] present. In addition, we compared the foliar concentrations of these elements in C. sciadophylloides with those in four different deciduous tree species. The mean of foliar (137)Cs concentration in C. sciadophylloides was 28.1 kBq kg(-1) DW, one order of magnitude higher than that found in the other species. The (137)Cs concentrations were in the order of leaves > bark > wood. The wood of the treetop, leaf scars, and roots contained higher amounts of (137)Cs than that of the trunk. From the distribution of (137)Cs in C. sciadophylloides, we confirmed that (137)Cs tends to accumulate in the young growing parts. The difference in the distribution of (137)Cs and (133)Cs indicated that surface uptake of (137)Cs occurs. A significant correlation between K and (137)Cs concentrations in each organ was found, which suggested that (137)Cs in the plant body is transferred through the same pathway as K. On the other hand, there was no correlation between foliar K and (137)Cs concentrations, implying that the uptake ratio of K to (137)Cs was different for each individual. To determine the factors driving specific (137)Cs accumulation and/or the variability of the ratio between K and (137)Cs, the distribution of (137)Cs and the root in soil, the difference of the expression of transporter, and the existence of mycorrhizal fungi should be considered. However, further research is required.
通过对福岛第一核电站事故后放射性污染的评估，有报道称，该事故现场的一些刺楸幼苗所含放射性铯（（134）、（137）Cs）浓度高于其他植物。为评估刺楸对（137）Cs的植物修复特性，我们旨在量化刺楸中（137）Cs的积累情况。我们测量了从福岛县川俣镇森林采集的刺楸各器官中的（137）Cs浓度，以及其他元素[钾（K）、铷、（133）Cs、钙、锶和锰]的浓度。此外，我们还比较了刺楸与四种不同落叶树种叶片中这些元素的浓度。刺楸叶片中（137）Cs浓度的平均值为28.1 kBq kg-1 DW，比其他树种高出一个数量级。（137）Cs浓度顺序为叶片＞树皮＞木材。树梢、叶痕和根部木材中的（137）Cs含量高于树干。从刺楸中（137）Cs的分布情况来看，我们证实（137）Cs倾向于在生长旺盛的幼嫩部位积累。（137）Cs和（133）Cs分布的差异表明存在（137）Cs的表面吸收。各器官中K和（137）Cs浓度之间存在显著相关性，这表明植物体内的（137）Cs与K通过相同途径转运。另一方面，叶片中K和（137）Cs浓度之间没有相关性，这意味着每个个体K与（137）Cs的吸收比例不同。为确定驱动特定（137）Cs积累和/或K与（137）Cs比例变化的因素，应考虑（137）Cs在土壤中的分布与根系情况、转运体表达差异以及菌根真菌的存在。然而，还需要进一步研究。
