Nanoparticulate micronutrients and fungicides have shown tremendous potential to increase plant biomass, reduce disease, increase yields, and to promote more efficient use of applied fertilizers. Despite the growing evidence of the benefits of nano-enabled agrochemicals, there is limited knowledge about the properties of nanomaterials that lead to efficient uptake and translocation. This study evaluated the effects of NP dissolution rate and charge on their uptake into hydroponically grown wheat plants. Three ~30nm PVP-coated Cu-based NPs with different dissolution rates (CuO, CuS, and CuHPO4) were evaluated to assess the influence of dissolution rate on the uptake and persistence of metals in the wheat plants. Approximately 4nm CeO2 NPs with modified dextran coatings were used to assess the effect of NP charge (+, -, neutral) on their affinity for roots and their translocation potential. Total metal uptake was measured, and synchrotron-based µ-X-ray fluorescence (XRF) and fast X-ray Absorption Near Edge Structure (XANES) was used to determine the distribution and speciation of metals in plant roots and leaves. The charge on 4-nm CeO2 NPs affected their attachment to roots, as well as their uptake and translocation. While the positively charged CeO2 NPs attached to roots better, only the neutral and negative charged NPs were able to translocate to the leaves. Moreover, the spatial distribution of those particles in wheat leaves was non-uniform. XANES mapping indicated that Ce was present as intact CeO2 NPs in the vasculature, but up to 20% Ce(III) was detected in other regions. Solubility also greatly affects the distribution and persistence of Cu-based nanoparticulate amendments. The particles with a greater dissolution rate led to more rapid uptake of Cu into the root tips. Less soluble materials attached to the entire outer root surface. After 48 hours of recovery in metal free medium, only the less soluble particles showed continued Cu associated with the roots (Figure 1). These findings indicate that the nanoparticle properties may be tuned (e.g. dissolution rate and charge) to provide the desired uptake and translocation.

Tuning NP properties for optimizing plant uptake and translocation

253rd National Meeting (2017)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.