Guo Xin-Peng, Chen Xi, Tu Chun-Xia, Fan Yu-Meng, Wang Ming-Xuan, Zhao Zheng-Qin, Yang Shi-Yi, Cui Lan-Lan, Wu Guo, Lai Jin-Long, Li Qun
College of Life Science, Sichuan Normal University, Chengdu 610101, China.
College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China.
Plants (Basel). 2025 Sep 1;14(17):2711. doi: 10.3390/plants14172711.
Cadmium (Cd) is a major co-occurring, highly toxic heavy metal in uranium (U) tailings that poses synergistic risks to ecological and human health. This study aimed to investigate the effects of Cd on U accumulation and phytotoxicity in plants using radish ( L.) as a model organism under hydroponic conditions. Treatments included U alone (25 μM and 50 μM), low-concentration Cd alone (10 μM), and U + Cd co-treatments (U25 + Cd and U50 + Cd). Results revealed that exposure exerted minimal phytotoxicity, whereas U treatment induced severe root toxicity, characterized by cell death and an 11.9-63.8% reduction in root biomass compared to the control. Notably, U + Cd co-treatment exacerbated root cell death and biomass loss relative to U alone. Physiologically, elevated U concentrations significantly increased superoxide anion radical (O) production rate, hydrogen peroxide (HO) content, and malondialdehyde (MDA)-a marker of oxidative damage-inducing cellular oxidative stress. Under U + Cd co-treatment, O production, HO content, and MDA levels in radish roots were all significantly higher than under U alone. Concurrently, activities of antioxidant enzymes (superoxide dismutase [SOD], catalase [CAT], and peroxidase [POD]) were lower in U + Cd-treated roots than in U-treated roots, further exacerbating oxidative damage. Regarding heavy metal accumulation, the content of U in radish under U + Cd treatment was significantly higher than that in the U treatment group. However, no significant differences were observed in the expression of uranium (U)-related transport genes (, , and ) between the single U treatment and the U-Cd co-treatment. Notably, the inhibitory effect of -a gene associated with Cd transport-was weakened under the coexistence of U, indicating that U exacerbates toxicity by promoting Cd transport. This study shows that Cd appears to enhance the accumulation of U in radish roots and exacerbate the phytotoxicity of U.
镉（Cd）是铀（U）尾矿中一种主要的伴生剧毒重金属，对生态和人类健康构成协同风险。本研究旨在以萝卜（L.）为模式生物，在水培条件下研究镉对植物中铀积累和植物毒性的影响。处理包括单独的铀（25 μM和50 μM）、单独的低浓度镉（10 μM）以及铀+镉联合处理（U25+Cd和U50+Cd）。结果表明，镉暴露产生的植物毒性最小，而铀处理诱导了严重的根部毒性，其特征是细胞死亡，与对照相比根生物量减少了11.9 - 63.8%。值得注意的是，与单独的铀处理相比，铀+镉联合处理加剧了根细胞死亡和生物量损失。在生理方面，铀浓度升高显著提高了超氧阴离子自由基（O）产生速率、过氧化氢（HO）含量以及丙二醛（MDA，氧化损伤标志物）含量，从而诱导细胞氧化应激。在铀+镉联合处理下，萝卜根中的O产生量、HO含量和MDA水平均显著高于单独铀处理。同时，铀+镉处理的根中抗氧化酶（超氧化物歧化酶[SOD]、过氧化氢酶[CAT]和过氧化物酶[POD]）的活性低于铀处理的根，进一步加剧了氧化损伤。关于重金属积累，铀+镉处理下萝卜中的铀含量显著高于铀处理组。然而，在单一铀处理和铀 - 镉联合处理之间，与铀（U）相关的转运基因（、和）的表达未观察到显著差异。值得注意的是，与镉转运相关的基因-a的抑制作用在铀共存时减弱，表明铀通过促进镉转运加剧毒性。本研究表明，镉似乎增强了铀在萝卜根中的积累并加剧了铀的植物毒性。
