Assessing the mitigation of Pb toxicity by the synergistic application of Oxalic acid and salicylic acid on maize plants

Abstract

We investigated the effects of Pb, oxalic acid (OA), and salicylic acid (SA) on the physiological and biochemical markers of maize (Zea mays L.) plants. The plants of Zea mays were subjected to treatments for 15, 30, and 45 days at doses of Pb at 0.5 mM, SA at 25 mg/l, and OA at 25 mg/l and SA+OA at 25 mg/l each. Plants under Pb stress displayed decreased relative water content, anthocyanin, carotenoid, and xanthophyll pigments, total carbohydrate content as well as growth metrics. SEM demonstrated that the stomatal conductance of Zea mays plants during Pb stress was decreased. The Zea mays plants had increased stomatal conductance in addition to improved growth metrics on the combined application of SA and OA. In Zea mays, the heavy metal Pb increased O2- generation, H2O2, and oxidative damage. On the other hand, SA + OA treatment of Zea mays plants reduced the adverse effects of heavy metals by decreasing oxidative stress, which resulted in suppressed O2- production and H2O2, as well as elevated SOD and GPOX enzyme activity. The application's exceptional efficacy in lowering Pb toxicity in maize plants suggests that OA + SA can enhance plant growth and development at the physiological level.