Effects of iron oxide nanoparticles (Fe3O4) and salinity on growth, photosynthesis, antioxidant activity and distribution of mineral elements in wheat (Triticum aestivum)

Soil salinisation is one of the main abiotic stresses decreasing crop productivity. Here, we show that the plant treatment with iron oxide (Fe3O4) nanoparticles (NPs) may be a promising solution for reducing the negative impact of soil salinity on plant performance. For this purpose, effects of the NPs on growth, photosynthesis, pro-/antioxidant, redox balance and the content of mineral elements in 19-day-old wheat (Triticum aestivum) plants under soil salinity were studied. Seed treatment with NPs (200 and 500 mg L-1) enhanced growth and photosynthetic rate in leaves. Moderate salinity stress (150 mM NaCl) led to a decrease in plant biomass as well as the rate of photosynthesis and PSII activity; leaf photosynthetic characteristics were also suppressed by lower (75 mM NaCl) salinity treatment. However, seed pre-treatment with the NPs partially eliminated the negative effect of the salt on growth, PSII activity and photosynthesis. Also, we observed a decrease in the content of malondialdehyde (MDA) and an increase in ascorbate and total peroxidase activity in the plant leaves upon combined treatment with NaCl and the NPs compared with treatment with NaCl alone. The combined treatment with the NPs and salinity also led to a noticeable increase in the content of Fe and Mn in the shoot. It was concluded that Fe3O4 NPs can enhance plant growth by improving photosynthetic characteristics, antioxidant balance and the availability of iron and manganese ions, under conditions of soil salinisation.