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

Abstract

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.

Transcriptome Analysis of Cadmium-Treated Roots in Maize (Zea mays L.)

“…Cadmium accumulation in cultivated soil has considerably increased over the last decade, and most crop plants, including maize, suffer from Cd toxicity in polluted environments (Valko et al, 2005; Anjum et al, 2015). Therefore, determining the molecular mechanisms involved in the responses to Cd stress would enable researchers to explore the potential Cd-defensive strategies that may occur in maize plants.…”

Lead toxicity in rice: effects, mechanisms, and mitigation strategies—a mini review

“…Roots are the first organ exposed to Pb and thus can be a major storage organ for Pb (mostly in tolerant cultivars) or can play an intermediary role for exporting the Pb ions from soil to the aboveground plant parts (in case of sensitive cultivars) (Fangmin et al 2006). Unlike some other higher plants, i.e., maize (Anjum et al 2015) and Brassica (Ali et al 2014), rice is neither a better metal accumulator (plants that are able to biodegrade or biotransform the pollutants/contaminants from active to inactive form in their tissues and may survive even at high levels of contaminates in their tissues) nor a good metal excluders (that restrain the uptake of contaminants in to their organs and avoid to make a part of their biomass; however, can be regarded as a good indicator (translocate and accumulate metals to different organs depending on the environmental toxicity and genotype) (Liu et al 2003). However, different rice genotypes show differential uptake and translocation properties.…”

Paxillus involutus-Facilitated Cd2+ Influx through Plasma Membrane Ca2+-Permeable Channels Is Stimulated by H2O2 and H+-ATPase in Ectomycorrhizal Populus × canescens under Cadmium Stress

“…It has been repeatedly shown that the antioxidant enzyme activities are activated under heavy metal stresses (Schützendübel et al, 2001, 2002; Rozpądek et al, 2014; Chen et al, 2015; Tan et al, 2015). The enhanced activities of superoxide dismutase, peroxidase, catalase, and ascorbate peroxidase play an important role in scavenging the Cd 2+ -elicited H 2 O 2 in plants (Garg and Aggarwal, 2012; Anjum et al, 2015; Tan et al, 2015). To combat Cd 2+ -induced superoxide and H 2 O 2 , P. × canescens plants were found to rely mainly on antioxidant enzymes and the formation of the potential radical scavenging molecules, such as proline, sugar alcohols and soluble phenolics (He et al, 2011).…”