Role of Nickel in plants: a review

Abstract

Nickel (Ni) is the furthermost known indispensable micronutrient for optimum growth and physiological functioning in higher plants. Although required in trace amounts—generally less than 0.5 mg kg{ ¹ of dry biomass—Ni is vital for various metabolic and developmental processes. Due to its very low yet vital concentration, it is often mentioned to as a “nano-nutrient.” Functioning primarily as a component of metalloenzymes, nickel is crucial for the activation of key enzymes such as urease and glyoxalase I. It is intricately involved in nitrogen metabolism, seed germination, photosynthesis, antioxidant defence mechanisms, and other specialized physiological pathways. Nickel is particularly vivacious for the hydrolysis of urea-based nitrogen via urease and for alleviating abiotic and oxidative stresses through the glyoxalase (Gly) and glutathione (GSH) detoxification cycles. Furthermore, the limited bioavailability of Ni constrains urease synthesis in plants which can significantly reduce the emission of nitrogen-based pollutants such as nitrous oxide and nitrites. This review critically examines the environmental availability (in soil), physiological significance, enzymatic functions, and systemic impacts of Ni on plants.