Cell Imaging and Ultrastructure Research, University of Vienna, Althanstraße 14, 1090, Vienna, Austria.
Cell Imaging and Ultrastructure Research, University of Vienna, Althanstraße 14, 1090, Vienna, Austria.
J Environ Radioact. 2021 Apr;229-230:106544. doi: 10.1016/j.jenvrad.2021.106544. Epub 2021 Feb 5.
Uranium (U) is a naturally occurring metal; its environmental levels can be increased due to processes in the nuclear industry and fertilizer production. The transfer of U in the food chain from plants is associated with deleterious chemical and radiation effects. To date, limited information is available about U toxicity on plant physiology. This study investigates the responses of metal-accumulating plants to different concentrations of U. The plants Noccaea caerulescens and Noccaea goesingense are known as metal hyperaccumulators and therefore could serve as candidates for the phytoremediation of radioactive hotspots; Plantago major is a widely used pharmaceutical plant that pioneers polluted grounds and therefore should not contain high concentrations of toxic elements. The experimental plants were grown hydroponically at U concentrations between 1 μM and 10 mM. The content of U and essential elements was analyzed in roots and leaves by ICP-MS. The amount of accumulated U was influenced by its concentration in the hydroponics. Roots contained most of the metal, whereas less was transported up to the leaves, with the exception of N. goesingense in a medium concentration of U. U also influenced the nutrient profile of the plants. We localized the U in plant tissues using EDX in the SEM. U was evenly distributed in roots and leaves of Noccaea species, with one exception in the roots of N. goesingense, where the central cylinder contained more U than the cortex. The toxicity of U was assessed by measuring growth and photosynthetic parameters. While root biomass of N. caerulescens was not affected by U, root biomass of N. goesingense decreased significantly at high U concentrations of 0.1 and 10 mM and root biomass of P. major decreased at 10 mM U. Dry weight of leaves was decreased at different U concentrations in the three plant species; a promotive effect was observed in N. caerulescens at lowest concentration offered. Chlorophyll a fluorescence was not affected or negatively affected by U in both Noccaea species, whereas in Plantago also positive effects were observed. Our results show that the impact of U on Plantago and Noccaea relates to its external concentration and to the plant species. When growing in contaminated areas, P. major should not be used for medicinal purpose. Noccaea species and P. major could immobilize U in their rhizosphere in hotspots contaminated by U, and they could extract limited amounts of U into their leaves.
铀（U）是一种天然存在的金属；其环境水平可能因核工业和肥料生产过程而增加。铀在食物链中的转移与有害的化学和辐射效应有关。迄今为止，关于铀对植物生理学的毒性的信息有限。本研究调查了金属积累植物对不同浓度铀的反应。众所周知，Noccaea caerulescens 和 Noccaea goesingense 是金属超积累植物，因此可以作为放射性热点植物修复的候选者；车前草是一种广泛使用的药用植物，它可以在污染的土地上开拓先驱，因此不应含有高浓度的有毒元素。实验植物在浓度为 1μM 至 10mM 的水培条件下生长。通过 ICP-MS 分析根和叶中的 U 和必需元素含量。根系中积累的 U 量受水培中 U 浓度的影响。大多数金属存在于根部，而向叶片中的运输较少，除了 N. goesingense 在中等浓度的 U 中。U 还影响植物的营养状况。我们使用 SEM 中的 EDX 定位植物组织中的 U。U 在 Noccaea 物种的根和叶中均匀分布，除了 N. goesingense 的根中有一个例外，其中中央柱含有比皮层更多的 U。通过测量生长和光合作用参数来评估 U 的毒性。虽然 N. caerulescens 的根生物量不受 U 的影响，但 N. goesingense 的根生物量在 0.1 和 10mM 的高 U 浓度下显著下降，而 P. major 的根生物量在 10mM U 下下降。三种植物物种的叶片干重均在不同的 U 浓度下下降；在最低浓度下观察到 N. caerulescens 的促进作用。在两种 Noccaea 物种中，叶绿素 a 荧光均未受 U 影响或受到负面影响，而在 Plantago 中也观察到了积极影响。我们的结果表明，U 对 Plantago 和 Noccaea 的影响与其外部浓度和植物物种有关。当在污染地区生长时，不应将 P. major 用于药用目的。Noccaea 物种和 P. major 可以将 U 固定在其根际中，从而在 U 污染的热点地区固定 U，并且可以将有限量的 U 提取到叶片中。
