Van Doan Cong, Mannino Giuseppe, Gatti Noemi, Maghrebi Moez, Vigani Gianpiero, Maffei Massimo E
Department of Life Sciences and Systems Biology, Plant Physiology Unit, University of Turin, Via Quarello15/a, Turin 10135, Italy.
Department of Life Sciences and Systems Biology, Plant Physiology Unit, University of Turin, Via Quarello15/a, Turin 10135, Italy.
Plant Sci. 2025 Sep 5;362:112745. doi: 10.1016/j.plantsci.2025.112745.
Cerium (Ce), the most abundant of the rare Earth elements (REEs), is increasingly recognized as an environmental contaminant due to its growing applications in various industrial and agricultural sectors. This study investigates the physiological, biochemical, and molecular responses of Brassica rapa L. plants to varying concentrations of Ce exposure to elucidate its effects on plant growth, metabolism, and stress responses. Through chemical analytical, biochemical, and gene expression methods, we revealed a biphasic (hormetic) effect of Ce on B. rapa. Low-level Ce exposure (1 µM) stimulated plant growth, evidenced by increased leaf area and fresh biomass. Conversely, elevated Ce concentrations (1 mM and 10 mM) induced significant photosynthetic dysfunction, characterized by diminished chlorophyll a and b content, impaired photosystem II (PSII) efficiency, and altered chlorophyll fluorescence. Ce exposure also modulated oxidative stress responses, exhibiting a hormetic pattern in reactive oxygen species (ROS) accumulation, alongside a general increase in proline. Secondary metabolism was selectively impacted, with higher Ce levels specifically promoting the accumulation of kaempferol derivatives. Mineral nutrient analysis revealed substantial Ce accumulation in leaves and a concomitant decrease in essential elements (Al, Se, Na). Gene expression analysis further elucidated that Ce exposure triggered differential expression of genes involved in carotenoid and flavonoid biosynthesis, chlorophyll metabolism, and ion transport. These comprehensive findings offer novel insights into the multifaceted physiological, biochemical, and molecular responses of B. rapa to Ce, underscoring both the potential ecological risks of Ce contamination and the intricate adaptive strategies employed by plants under REE stress.
铈（Ce）是稀土元素（REEs）中含量最为丰富的元素，由于其在工农业各领域的应用日益广泛，越来越被视为一种环境污染物。本研究调查了青菜（Brassica rapa L.）植株对不同浓度铈暴露的生理、生化及分子响应，以阐明其对植物生长、代谢和应激反应的影响。通过化学分析、生化及基因表达方法，我们揭示了铈对青菜的双相（兴奋效应）作用。低水平铈暴露（1 μM）刺激了植物生长，叶面积和鲜生物量增加即为明证。相反，铈浓度升高（1 mM和10 mM）会导致显著的光合功能障碍，其特征为叶绿素a和b含量降低、光系统II（PSII）效率受损以及叶绿素荧光改变。铈暴露还调节了氧化应激反应，在活性氧（ROS）积累方面呈现兴奋效应模式，同时脯氨酸普遍增加。次生代谢受到选择性影响，较高的铈水平特别促进了山奈酚衍生物的积累。矿质营养分析表明叶片中大量积累了铈，同时必需元素（铝、硒、钠）减少。基因表达分析进一步阐明，铈暴露引发了参与类胡萝卜素和黄酮生物合成、叶绿素代谢及离子转运的基因差异表达。这些全面的研究结果为青菜对铈的多方面生理、生化及分子响应提供了新见解，凸显了铈污染的潜在生态风险以及植物在稀土元素胁迫下所采用的复杂适应策略。
