Salicylic acid application mitigates plant oxidative stress by chelating with essential metals of soil

This study explores the role of salicylic acid (SA) in reducing oxidative stress in plants by chelating essential metal ions. In vitro experiments examined SA's interaction with metal ions (Mg, Ca, Mn, Fe, Co, Ni, Cu, Zn, Mo), showing that SA and its metal complexes exhibit higher antioxidant activity than ascorbic acid (AA) with radical scavenging activity (RSA) 28.22 % and electrode potential of −0.74 V. Among the complexes, the Mn(II)-SA complex demonstrated the highest antioxidant activity with RSA 64.52 % and electrode potential of −0.9 V. In situ experiments revealed that SA forms complexes more quickly in soil conditions, suggesting effective in-plant chelation. In vivo tests on pesticide-stressed wheat plants showed that the Mn(II)-SA complex enhanced antioxidant enzyme activities (superoxide dismutase (SOD) and peroxidase (POD)). Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) analysis confirmed that SA-treated plants had higher metal content, supporting the idea that SA enhances metal uptake through chelation, thereby mitigating oxidative stress.