Iron (III) oxide nanoparticles alleviate arsenic induced stunting in Vigna radiata.

Iron nanoparticles (NPs) are widely used for the removal of arsenic from water. In this study, we evaluated the interaction between arsenate (AsO 4 ³⁻) and Fe 2 O 3 -NPs on early seedling growth of Vigna radiata. Seedlings were raised in AsO 4 ³⁻ and Fe 2 O 3 -NPs, alone and in combination. While Fe 2 O 3 -NPs slightly promoted seedling growth, AsO 4 ³⁻ reduced seedling growth drastically. AsO 4 ^3--induced decline in the seedling growth was recovered by Fe 2 O 3 -NPs. In contrast, equivalent concentrations of FeCl 3 , alone and together with AsO 4 ³⁻, inhibited seed germination completely. Lower arsenic content in seedlings raised in the presence of Fe 2 O 3 -NPs indicated that Fe 2 O 3 -NPs restricted arsenic uptake. Ability of Fe 2 O 3 -NPs to restrict the arsenic uptake of the seedlings was due to adsorption of AsO 4 ³⁻, as revealed by transmission and scanning electron microscopy. Non-toxic levels of iron in seedlings were due to restriction of Fe 2 O 3 -NPs to root-surface. AsO 4 ³⁻ enhanced the ferric chelate reductase activity of root which was recovered by Fe 2 O 3 -NPs. The AsO 4 ^3--induced oxidative stress, evident from high levels of proline, H 2 O 2 and malondialdehyde, and lowered root oxidisability was ameliorated by Fe 2 O 3 -NPs. AsO 4 ³-induced enhancement in total antioxidant capacity, superoxide dismutase and catalase activity, and decline in guaiacol peroxidase activity were antagonized by Fe 2 O 3 -NPs. Our findings reveal that Fe 2 O 3 -NPs provide effective resistance/amelioration to arsenic toxicity by reducing arsenic availability to plants. Image 1 • Fe 2 O 3 nanoparticles reduce arsenic uptake in Vigna radiata seedlings. • Fe 2 O 3 nanoparticles reduce arsenic availability to seedlings via sorption. • Fe 2 O 3 nanoparticles restricted to root surface limit transport of toxic iron levels. • Fe 2 O 3 nanoparticles antagonise arsenate induced oxidative stress in seedlings. [ABSTRACT FROM AUTHOR]