Nickel (Ni) excess delays plant growth due to damage to root and leaf structures, reducing nutrient uptake, and carbon fixation, respectively. 24-Epibrassinolide (EBR) is a biodegradable plant growth regulator extracted from plant tissues and is highly efficient against oxidative stress. The objective of this research is to determine whether EBR can improve tolerance to toxic metals and the possible mechanism involved by evaluating the root and leaf structures of soybean plants under high Ni concentrations. The experiment was randomized with four treatments, including two Ni concentrations (0 and 200 µM Ni, described as – Ni²⁺ and + Ni²⁺, respectively) and two concentrations of 24-epibrassinolide (0 and 100 nM EBR, described as – EBR and + EBR, respectively). Ni²⁺ excess provoked damage to root and leaf structures, causing anatomical disorders in these tissues. In roots, EBR increased the epidermis (27%), protecting the root against Ni²⁺ ions. For leaf tissue, significant increases in palisade (11%) and spongy parenchyma (29%) were detected in plants sprayed with EBR and exposed to Ni²⁺, which were intrinsically related to stomatal density and stomatal functionality. Our results confirm that pretreatment with 100 nM EBR clearly mitigated the anatomical disorders occasioned by excess Ni on the leaf and root structures of soybean plants.

镍（Ni）过量会因破坏根和叶结构，分别减少养分吸收和固碳而延缓植物生长。24-表油菜素内酯（EBR）是一种从植物组织中提取的可生物降解的植物生长调节剂，对氧化应激非常有效。这项研究的目的是通过评估高Ni浓度下大豆植物的根和叶结构来确定EBR是否可以提高对有毒金属的耐受性以及可能的机理。该实验采用4种治疗方法随机分组，包括两种浓度的Ni（0和200 µM Ni，分别表示为– Ni ²⁺和+ Ni ²⁺）和两种浓度的24-表油菜素内酯（0和100 nM EBR，表示为– EBR和+ EBR）。镍²⁺过度的刺激会破坏根和叶的结构，导致这些组织的解剖结构异常。在根部，EBR可增加表皮（27％），保护根部免受Ni ²⁺离子的侵害。对于叶片组织，在喷有EBR并暴露于Ni ^2+的植物中检出的栅栏（11％）和海绵状薄壁组织（29％）显着增加，这与气孔密度和气孔功能本质相关。我们的结果证实，用100 nM EBR进行预处理可以明显减轻大豆植株叶片和根部结构中过量Ni引起的解剖异常。