Soil polluted with heavy metals is a continuous threat to global crop production. The present study deals with growth, biochemical attributes, photosynthetic pigments, antioxidant responses and gyloxalase systems of mustard plants under varying concentrations of nickel (Ni) stress. Ni stress (150 µM) reduced growth (shoot length by 34.46% and root length by 52.49%), chlorophyll (57.63%), gas exchange parameters (PN by 36.84%, A by 55.61%), leaf relative water content (LRWC by 24.34%), and enhanced hydrogen peroxide (H2O2 by3.23 fold) malondialdehyde (MDA by 2.07 fold), and methylglyoxal (MG by 3.32 fold) content. Si (10− 5 M) application ameliorated the negative effects of Ni on growth, chlorophyll content, photosynthetic traits and also elevated the activities of antioxidant enzymes and enzymes associated with the ascorbate glutathione (AsA-GSH) cycle and glyoxylase systems. Nevertheless, Si application to Ni-stressed plants had an additive effect on the enzyme activities of antioxidants and enzymes of AsA-GSH cycle. Exogenous Si supplementation elevated endogenous Si content which decreased root to shoot Ni translocation and maintained optimum osmolyte and secondary metabolite accumulation. We conclude that Si-induced Ni stress tolerance in mustard plants could be correlated with the upregulation of enzymes associated with antioxidant defence, glyoxalase detoxification systems and sufficient primary and secondary osmoprotectant accumulation.

中文翻译：

---

硅通过调节芥菜中的抗氧化防御和乙二醛酶系统减轻镍诱导的氧化应激

被重金属污染的土壤对全球作物生产构成持续威胁。本研究涉及芥菜植物在不同浓度的镍 (Ni) 胁迫下的生长、生化属性、光合色素、抗氧化反应和乙二醛酶系统。Ni 胁迫 (150 µM) 降低生长（茎长 34.46%，根长 52.49%）、叶绿素（57.63%）、气体交换参数（PN 36.84%、A 55.61%）、叶片相对含水量（LRWC） 24.34%），以及提高过氧化氢（H2O2 为 3.23 倍）丙二醛（MDA 为 2.07 倍）和甲基乙二醛（MG 为 3.32 倍）的含量。Si (10− 5 M) 应用改善了 Ni 对生长、叶绿素含量、光合特性，并且还提高了抗氧化酶和与抗坏血酸谷胱甘肽 (AsA-GSH) 循环和乙醛酸酶系统相关的酶的活性。然而，将硅应用于镍胁迫的植物对抗氧化剂和 AsA-GSH 循环酶的酶活性具有累加作用。外源Si补充提高了内源Si含量，减少了根向芽Ni的易位并保持了最佳渗透物和次生代谢物的积累。我们得出结论，芥菜植物中硅诱导的镍胁迫耐受性可能与与抗氧化防御、乙二醛酶解毒系统和足够的初级和次级渗透保护剂积累相关的酶的上调有关。将硅应用于镍胁迫的植物对抗氧化剂和 AsA-GSH 循环酶的酶活性具有累加作用。外源Si补充提高了内源Si含量，减少了根向芽Ni的易位并保持了最佳渗透物和次生代谢物的积累。我们得出结论，芥菜植物中硅诱导的镍胁迫耐受性可能与与抗氧化防御、乙二醛酶解毒系统和足够的初级和次级渗透保护剂积累相关的酶的上调有关。将硅应用于镍胁迫的植物对抗氧化剂和 AsA-GSH 循环酶的酶活性具有累加作用。外源Si补充提高了内源Si含量，减少了根向芽Ni的易位并保持了最佳渗透物和次生代谢物的积累。我们得出结论，芥菜植物中硅诱导的镍胁迫耐受性可能与与抗氧化防御、乙二醛酶解毒系统和足够的初级和次级渗透保护剂积累相关的酶的上调有关。