The role of exogenous silicon to mitigate Al2O3 nanoparticle-induced toxicity in barley (Hordeum vulgare L.)

摘要

In this study, we used silicon (Si, in the form of K 2 SiO 3 , 2 mM) to alleviate the toxicity of aluminum oxide (Al 2 O 3 ) nanoparticles (NPs) in barley (Hordeum vulgare L.). Using Inductively Coupled Plasma-Mass Spectroscopy (ICP-MS) analyses, we showed that the Al 2 O 3 NPs were taken up by barley plants. Barley growth was negatively affected by the addition of 3 g l -1 nano-Al 2 O 3 , whereas the diminishing effect of NPs on barley growth was not obvious when 1 g l -1 nano-Al 2 O 3 was applied, indicating that the nano-Al 2 O 3 action is dependent on nano-Al 2 O 3 dose. Si pretreatment ameliorated toxic effects of high nano-Al 2 O 3 on root growth. Si pretreatment did not decrease nano-Al 2 O 3 entry into roots but reduced nano-Al 2 O 3 accumulation in the shoot. The restriction of the root-to-shoot translocation of nano-Al 2 O 3 was one of the important mechanisms for Si to mitigate high nano-Al 2 O 3 toxicity. The occurrence of oxidative stress was found under 3 g l 1 nano-Al 2 O 3 treatment, as evaluated by the accumulation of malondialdehyde (MDA). Exogenous addition of Si could alleviate toxicity symptoms induced by Al 2 O 3 nanoparticles by reducing lipid peroxidation via enhancing antioxidant activity of catalase as well as by limiting the root-to-shoot translocation of nano-Al 2 O 3 . These data provide the first direct evidence that the Si pretreatment ameliorates nano Al 2 O 3 phytotoxicity in plants.