Effect of Silicon Nanoparticles on Tomato Plants Exposed to Two Forms of Inorganic Arsenic

Abstract

In the environment arsenic (As) can be found mainly as arsenite (AsIII) and arsenate (AsV), which are highly toxic and threaten food security. Currently, there is great attention on the effects of silicon dioxide nanoparticles (SiO2 NPs) on plant development, and their ability to restrict As uptake. The results show that the two forms of As negatively impacted aerial dry biomass and fruit yield. Silicon content is lower in roots than in leaves. It is observed that AsIII is the form that accumulates the most in the root; in addition, the SiO2 NPs reduce the translocation of AsV. The data show that AsIII induced a negative effect on the uptake of Ca, P, Mg, and Cu, while SiO2 NPs enhances the accumulation of Fe and Zn when exposed to AsIII. The two forms of As do not impact chlorophyll content but increases when interacting with SiO2 NPs. Antioxidant enzymes APX, CAT, and SOD are higher in roots than in leaves. Phenols, flavonoids, and glutathione increased when SiO2 NPs interacted with AsIII in roots. H2O2 increases in roots and leaves by exposure to AsV and AsIII, and its interactions with SiO2 NPs, while in the fruit, H2O2 production decreases. As for the total antioxidant capacity ABTS is observed to increase by AsIII + SiO2 NPs only in roots. The bioactive compounds of the tomato fruits are modified by the treatments and the addition of SiO2 NPs alone increase in lycopene content. Therefore, our results reveal the negative impacts of AsIII, and that SiO2 NPs can at least partially mitigate As toxicity and reduce AsV translocation in tomatoes.

Keywords

• antioxidant defense system
• arsenate
• arsenite
• nanotechnology