Role of particle size-dependent copper bioaccumulation-mediated oxidative stress on Glycine max (L.) yield parameters with soil-applied copper oxide nanoparticles

Environ Sci Pollut Res Int. 2024 Apr;31(20):28905-28921. doi: 10.1007/s11356-024-33070-x. Epub 2024 Apr 2.

Abstract

Increased impetus on the application of nano-fertilizers to improve sustainable food production warrants understanding of nanophytotoxicity and its underlying mechanisms before its application could be fully realized. In this study, we evaluated the potential particle size-dependent effects of soil-applied copper oxide nanoparticles (nCuO) on crop yield and quality attributes (photosynthetic pigments, seed yield and nutrient quality, seed protein, and seed oil), including root and seed Cu bioaccumulation and a suite of oxidative stress biomarkers, in soybean (Glycine max L.) grown in field environment. We synthesized three distinct sized (25 nm = S [small], 50 nm = M [medium], and 250 nm = L [large]) nCuO with same surface charge and compared with soluble Cu2+ ions (CuCl2) and water-only controls. Results showed particle size-dependent effects of nCuO on the photosynthetic pigments (Chla and Chlb), seed yield, potassium and phosphorus accumulation in seed, and protein and oil yields, with nCuO-S showing higher inhibitory effects. Further, increased root and seed Cu bioaccumulation led to concomitant increase in oxidative stress (H2O2, MDA), and as a response, several antioxidants (SOD, CAT, POX, and APX) increased proportionally, with nCuO treatments including Cu2+ ion treatment. These results are corroborated with TEM ultrastructure analysis showing altered seed oil bodies and protein storage vacuoles with nCuO-S treatment compared to control. Taken together, we propose particle size-dependent Cu bioaccumulation-mediated oxidative stress as a mechanism of nCuO toxicity. Future research investigating the potential fate of varied size nCuO, with a focus on speciation at the soil-root interface, within the root, and edible parts such as seed, will guide health risk assessment of nCuO.

Keywords: Copper oxide nanoparticles; Micronutrients; Nanofertilizer; Oil crop; Phytotoxicity; Seed oil; Seed protein.

MeSH terms

  • Bioaccumulation
  • Copper*
  • Glycine max* / drug effects
  • Glycine max* / metabolism
  • Nanoparticles
  • Oxidative Stress*
  • Particle Size*
  • Soil Pollutants
  • Soil* / chemistry

Substances

  • Copper
  • Soil
  • Soil Pollutants
  • cupric oxide
  • cuprous oxide