Exogenous application of ascorbic acid mitigates cadmium toxicity and uptake in Maize (Zea mays L.).

Cadmium (Cd) contamination in agricultural soils is a prevalent environmental issue and poses potential threats to food security. Foliar ascorbic acid might prove a potent tool to alleviate toxicity of Cd toxicity in maize. An experiment was conducted with objectives to study exogenous ascorbic acid-modulated improvements in physiochemical attributes of maize under Cd toxicity. The experiment was conducted under completely randomized design. Treatments were comprised of varying concentrations of foliar ascorbic acid viz. 0.0, 0.1, 0.3, and 0.5 mM of AsA. Toxicity of Cd decreased the maize growth, increased lipid peroxidation, disturbed protein metabolism, and reduced the antioxidant defense capabilities compared with the control. However, foliar AsA significantly improved maize growth and development, photosynthetic capabilities, and protein concentrations in Cd-stressed maize plants. Meanwhile, the malondialdehyde contents and hydrogen peroxide accumulation levels in Cd-stressed maize plants decreased remarkably with increasing AsA concentrations. Furthermore, the combined treatments conspicuously boosted activities of superoxide dismutase, peroxidase, catalase, and glutathione reductase under the Cd stress alone. In addition, the application of AsA reduced the Cd uptake by 10.3-12.3% in grains. Conclusively, foliar ascorbic acid alleviated the negative effects of Cd stress in maize and improved photosynthetic processes, osmolytes, and antioxidant defense systems.

Cadmium toxicity in Maize (Zea mays L.): consequences on antioxidative systems, reactive oxygen species and cadmium accumulation.

Increased cadmium (Cd) accumulation in soils has led to tremendous environmental problems, with pronounced effects on agricultural productivity. Present study investigated the effects of Cd stress imposed at various concentrations (0, 75, 150, 225, 300, 375 µM) on antioxidant activities, reactive oxygen species (ROS), Cd accumulation, and productivity of two maize (Zea mays L.) cultivars viz., Run Nong 35 and Wan Dan 13. Considerable variations in Cd accumulation and in behavior of antioxidants and ROS were observed under Cd stress in both maize cultivars, and such variations governed by Cd were concentration dependent. Exposure of plant to Cd stress considerably increased Cd concentration in all plant parts particularly in roots. Wan Dan 13 accumulated relatively higher Cd in root, stem, and leaves than Run Nong 35; however, in seeds, Run Nong 35 recorded higher Cd accumulation. All the Cd toxicity levels starting from 75 µM enhanced H2O2 and MDA concentrations and triggered electrolyte leakage in leaves of both cultivars, and such an increment was more in Run Nong 35. The ROS were scavenged by the enhanced activities of superoxide dismutase, peroxidase, catalase, ascorbate peroxidase, and glutathione peroxidase in response to Cd stress, and these antioxidant activities were higher in Wan Dan 13 compared with Run Nong 35 at all Cd toxicity levels. The grain yield of maize was considerably reduced particularly for Run Nong 35 under different Cd toxicity levels as compared with control. The Wan Dan 13 was better able to alleviate Cd-induced oxidative damage which was attributed to more Cd accumulation in roots and higher antioxidant activities in this cultivar, suggesting that manipulation of these antioxidants and enhancing Cd accumulation in roots may lead to improvement in Cd stress tolerance.