Our research revealed that 24-epibrassinolide alleviated nickel toxicity in young Eucalyptus urophylla plants, inducing benefits on nutritional, physiological, biochemical, anatomical and morphological responses. Soil contamination by heavy metals may limit the Eucalyptus production. Disturbances caused by nickel (Ni) toxicity interfere with the absorption of other essential nutrients. 24-Epibrassinolide (EBR) is one form of brassinosteroid (BR) that provides benefits for plant metabolism under Ni toxicity. The aim of this study was to determine whether exogenous EBR can improve ionic homeostasis by evaluating nutrient concentrations, anatomical characteristics and chlorophyll fluorescence in young Eucalyptus urophylla plants subjected to Ni toxicity. The experiment was randomized into four treatments, including two Ni concentrations (0 and 600 μM Ni) and two 24-epibrassinolide concentrations (0 and 100 nM EBR). EBR significantly reduced Ni contents. Plants exposed to Ni2+ and sprayed with steroid had increases in the Ca2+/Ni2+ and Mn2+/Ni2+ ratios in the leaves of 38% and 15%, respectively, compared with the same treatment without EBR. The treatment of Ni2+ toxicity + EBR presented an increase of 42% in effective quantum yield of PSII photochemistry, when compared with plants exposed to Ni without EBR. Ni toxicity induced negative effects on stomatal functionality, but EBR application mitigated these effects. Benefits on effective quantum yield of PSII photochemistry after EBR spray can be related to increases in manganese contents. EBR reduced oxidative stress, alleviating the deleterious effects induced by Ni toxicity and inducing positive repercussions on antioxidant enzymes, photosynthetic pigments and biomass.

中文翻译：

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24-Epibrassinolide 减轻幼龄桉树 ST Blake 植物的镍毒性：营养、生理、生化、解剖和形态学反应

我们的研究表明，24-表油酸内酯减轻了尾叶桉幼苗的镍毒性，对营养、生理、生化、解剖和形态反应产生了益处。重金属对土壤的污染可能会限制桉树的生产。镍 (Ni) 毒性引起的干扰会干扰其他必需营养素的吸收。24-表油菜素内酯 (EBR) 是油菜素内酯 (BR) 的一种形式，可在 Ni 毒性下为植物代谢提供益处。本研究的目的是通过评估受镍毒害的尾叶桉幼树的营养浓度、解剖学特征和叶绿素荧光，确定外源 EBR 是否可以改善离子稳态。实验随机分为四个处理，包括两个 Ni 浓度（0 和 600 μM Ni）和两个 24-表布拉西内酯浓度（0 和 100 nM EBR）。EBR 显着降低了 Ni 含量。与没有 EBR 的相同处理相比，暴露于 Ni2+ 和喷洒类固醇的植物叶片中的 Ca2+/Ni2+ 和 Mn2+/Ni2+ 比率分别增加了 38% 和 15%。与没有 EBR 暴露于 Ni 的植物相比，Ni2+ 毒性 + EBR 的处理使 PSII 光化学的有效量子产率提高了 42%。Ni 毒性对气孔功能产生负面影响，但 EBR 应用减轻了这些影响。EBR 喷涂后 PSII 光化学有效量子产率的好处可能与锰含量的增加有关。EBR 减少氧化应激，