Hematite nanoparticles influence ultrastructure, antioxidant defenses, gene expression, and alleviate cadmium toxicity in Zea mays

[摘要] The present study describes the response of Zea mays to hematite nanoparticles (NPs) using five concentrations ranged from 500 to 8000 mg kg−1 , and Cd2+ concentrations (110 or 130 mg kg−1 Cd2+) only or combined with 500 mg kg−1 NPs, using soil culture. The endpoints measured were root/shoot growth, elements uptake, ultra-structural alterations, lipid peroxidation, some antioxidant enzyme activities, and their relative gene expressions. The results indicated that hematite NPs exhibited a dual behavior, in which 500 mg kg−1 NPs significantly enhanced maize growth, while 4000 and 8000 mg kg−1 NPs significantly increased lipid peroxidation and superoxide dismutase (SOD) activity displaying positive correlation with SOD expression in shoots (r = +0.472, p < .05). Ultrastructure micrographs revealed the appearance of aggregated NPs inside the vacuoles. The stunted growth, perturbed ultra-structure, and high lipid peroxidation were used as toxicity biomarkers for Cd2+. However, combined treatments of 500 mg kg−1 NPs and Cd2+ significantly stimulated growth and glutathione reductase activity, while significantly reduced catalase (CAT) activity displaying positive correlation with CAT expression in roots (r = +0.694, p < .01). In conclusion, hematite NPs could alleviate Cd2+ toxicity not at the level of antioxidant defense, but by affecting mechanisms of Cd2+ detoxification.

[学科分类] 纳米科学和纳米技术

[关键词] Cadmium;combined treatment;hematite nanoparticles;lipid peroxidation;maize;oxidative stress;reactive oxygen species