Bean Seedling Growth Enhancement Using Magnetite Nanoparticles.

Advanced fertilizers are one of the top requirements to address rising global food demand. This study investigates the effect of bare and polyethylene glycol-coated Fe3O4 nanoparticles on the germination and seedling development of Phaseolus vulgaris L. Although the germination rate was not affected by the treatments (1 to 1 000 mg Fe L-1), seed soaking in Fe3O4-PEG at 1 000 mg Fe L-1 increased radicle elongation (8.1 ± 1.1 cm vs 5.9 ± 1.0 cm for the control). Conversely, Fe2+/Fe3+(aq) and bare Fe3O4 at 1 000 mg Fe L-1 prevented the growth. X-ray spectroscopy and tomography showed that Fe penetrated in the seed. Enzymatic assays showed that Fe3O4-PEG was the least harmful treatment to α-amylase. The growth promoted by the Fe3O4-PEG might be related to water uptake enhancement induced by the PEG coating. These results show the potential of using coated iron nanoparticles to enhance the growth of common food crops.