Several factors have contributed to bring pressure on agriculture. In this context, nanomaterial properties can be explored to design more efficient fertilizers and therefore increase productivity. In the present study, the roots of Phaseolus vulgaris were immersed in several nano ZnO dispersions for 48 h. The absorption and transport phenomena were in vivo monitored by X-ray fluorescence spectroscopy (XRF) and X-ray absorption spectroscopy (XAS). The nanoparticle size, concentration and coating with surfactants affected the rate of Zn release and therefore its uptake. In vivo X-ray absorption spectroscopy showed that Phaseolus vulgaris takes up Zn bound to both citrate and malate, while entire nanoparticles were only absorbed when roots were injured. X-ray fluorescence microanalysis unravelled that besides xylem bundles, root to shoot Zn transport can take place through the cortex.

The increasing number of patents suggests that the use of nanoparticles (NPs) in agriculture will continue to grow in the future. Properties associated with nanosized objects might be desirable, but may pose a threat to the environment since the fate of nanomaterials is poorly understood. Seed treatment is an extensive practice to provide micronutrients and disease protection. This study investigates the effect of Ag₂S NPs, Ag⁰ NPs, and AgNO₃ (1, 100, and 1000 mg Ag per L) on the germination of Phaseolus vulgaris seeds and the mechanism of interaction in the seed coat. Ag treatments did not affect the germination rate. On the other hand, the development of seedlings was significantly improved by Ag₂S NPs while AgNO₃ showed a negative effect compared to the control (water). Silver from different sources was accumulated and biotransformed along the seed coat. Ag from the AgNO₃ treatment was found as AgCl and bound to oxygen, and Ag⁰ NPs underwent oxidative dissolution forming thiolate complexes. On the other hand, Ag₂S NPs did not show any detectable chemical changes. Silver distribution and speciation were investigated in the bean testa using μ-XRF and μ-XANES, while the macromolecular composition was assessed by ATR-FTIR. The Ag biotransformation depended on the source. For the FTIR results, it is possible to verify perturbations in the carbohydrate region as well as changes in the protein region. The combination of these results can contribute to building another step in the understanding of how nanoparticles can improve agricultural inputs and benefit food crops.