Reduction of arsenic toxicity in two rice cultivar seedlings by different nanoparticles

Abstract

In this study, we investigated arsenic uptake and enzymatic activities in rice seedlings after the addition of nanoparticles. Hydroponic experiments were conducted to investigate the effects of different nanomaterials (high-quality graphene oxide, multilayer graphene oxide, 20 nm hydroxyapatite (HA₂₀), 40 nm hydroxyapatite (HA₄₀), nano-Fe₃O₄ (nFe₃O₄) and nano-zerovalent iron [nFe]) on the biomass, arsenic uptake, and enzyme activities in seedlings of the rice cultivars T705 and X24. Compared with the control, the addition of different nanomaterials increased seedling growth, with X24 rice growing better than T705 rice. Nanomaterials effectively reduced arsenic uptake in T705 rice seedlings under low and high arsenic concentrations; however, they were only effective at lower arsenic concentrations in X24 seedlings. nFe₃O₄ and nFe performed better than other nanomaterials in preventing arsenic from being transported to the aboveground parts of the rice seedlings. Different nanomaterials obviously influenced enzyme activities in the T705 seedlings at low arsenic concentrations (≤ 0.8 mg L^-1). High-quality and multilayer graphene oxide decreased enzyme activities in the aboveground parts of the T705 seedlings, whereas, HA₂₀ and HA₄₀ increased the enzyme activities. nFe₃O₄ and nFe also reduced the effect of antioxidants in the aboveground parts of the T705 seedlings. Nanomaterials effectively reduced the arsenic uptake of T705 and X24 rice seedlings at low arsenic concentrations.

Keywords: Arsenic; Enzyme activity; Nanomaterial; Rice cultivar; Uptake.