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Little is known about the effects of surface modification on the interaction of nanoparticles (NPs) with plants. Tomato (Solanum lycopersicum L.) plants were cultivated in potting soil amended with bare and citric acid coated nanoceria (nCeO2, nCeO2+CA), cerium acetate (CeAc), bulk cerium oxide (bCeO2) and citric acid (CA) at 0–500 mg kg−1. Fruits were collected year-round until the harvesting time (210 days). Results showed that nCeO2+CA at 62.5, 250 and 500 mg kg−1 reduced dry weight by 54, 57, and 64% and total sugar by 84, 78, and 81%. At 62.5, 125, and 500 mg kg−1 nCeO2+CA decreased reducing sugar by 63, 75, and 52%, respectively and at 125 mg kg−1 reduced starch by 78%, compared to control. The bCeO2 at 250 and 500 mg kg−1, increased reducing sugar by 67 and 58%. In addition, when compared to controls, nCeO2 at 500 mg kg−1 reduced B (28%), Fe (78%), Mn (33%), and Ca (59%). At 125 mg kg−1 decreased Al by 24%; while nCeO2+CA at 125 and 500 mg kg−1 increased B by 33%. On the other hand, bCeO2 at 62.5 mg kg−1 increased Ca (267%), but at 250 mg kg−1 reduced Cu (52%), Mn (33%), and Mg (58%). Fruit macromolecules were mainly affected by nCeO2+CA, while nutritional elements by nCeO2; however, all Ce treatments altered, in some way, the nutritional quality of tomato fruit. To our knowledge, this is the first study comparing effects of uncoated and coated nanoceria on tomato fruit quality.

The effects of soil properties on nanomaterial (NM) interactions with plants are not well understood. Bean (Phaseolus vulgaris) plants were grown to maturity in natural soil (NS) or organic matter (OM)-enriched soil (ES) amended with either uncoated (Z-COTE), hydrophobically-coated (Z-COTE HP1) ZnO NMs, bulk ZnO, or ZnCl2 at 0–500 mg kg−1. At harvest, yield and seed nutrient composition were assessed. The soil × compound interaction reduced the maturation time by about 25 days and increased the seed yield (∼155%) in ES, compared to NS. In NS, ZnCl2 at 125 mg kg−1 produced 10% less seed protein than the control, and disregarding the concentration, seeds from ZnCl2 showed the highest relative sugar content (102%, compared with the other compounds), while in NS, seeds from Z-COTE HP1 accumulated the highest relative sugar content (44% more than Z-COTE and ZnCl2). In addition, seeds from ES + Z-COTE HP1 had 19% less Zn than the rest of the compounds. In ES, the OM enrichment and reduction in pH enhanced the accumulation of Zn (38%), K (64%), S (44%), P (83%), Mg (86%), Ca (70%), Fe (89%), and Mn (85%), but reduced Mo under Z-COTE HP1 and ZnCl2, in comparison to NS seeds. Compared to the controls, ZnCl2 at 500 mg kg−1 reduced the K content in NS and ES (25% and 13%) but increased the P content in NS (66%). In general, Z-COTE and Z-COTE HP1 affected seed nutritional elements in a similar manner. However, the results indicate that the effects of ZnO NMs in bean plants vary with soil composition.

It is essential to understand the interactions of engineered nanoparticles (ENPs) with additives used in agriculture and their impacts on crop plants. In this study, kidney bean (Phaseolus vulgaris) plants were grown in potting soil amended with either nano copper (nCu), bulk copper (bCu), or copper chloride (CuCl2) at 0, 50, and 100mg/kg, combined with 0, 10, or 100μM of kinetin (KN). Plant growth, Cu, micro and macroelement concentrations, chlorophyll content, and enzymatic activity were examined in 55-day old plants. Results showed that root Cu content was at least 10-fold higher, compared to other tissues. Accumulation of Cu in roots was decreased by 100μM KN up to 25%. A concentration-dependent increase of Cu content in leaves by Cu×KN was observed. Chlorophyll production was diminished by CuCl2+KN between 22 and 30%, showing a hormetic response. Catalase activity was repressed by 65% to 82% in bCu and CuCl2 treatments. From all essential elements, Ca, Mn, and P were reduced by 33% to 97% in bCu, CuCl2, and CuCl2+KN treatments. However, this did not impact stem elongation and tissue biomass that increased up to 55% under exposure to bCu and CuCl2. Our results demonstrate that KN combined with ionic Cu could have negative implications in kidney bean plants, since this combination impacted chlorophyll production and nutrient element accumulation.