Illya A. Medina-Velo

Copper nanoparticles/compounds impact agronomic and physiological parameters in cilantro (Coriandrum sativum)

The environmental impacts of Cu-based nanoparticles (NPs) are not well understood. In this study, cilantro (Coriandrum sativum) was germinated and grown in commercial potting mix soil amended with Cu(OH)2 (Kocide and CuPRO), nano-copper (nCu), micro-copper (μCu), nano-copper oxide (nCuO), micro-copper oxide (μCuO) and ionic Cu (CuCl2) at either 20 or 80 mg Cu per kg. In addition to seed germination and plant elongation, relative chlorophyll content and micro and macroelement concentrations were determined. At both concentrations, only nCuO, μCuO, and ionic Cu, showed statistically significant reductions in germination. Although compared with control, the relative germination was reduced by ∼50% with nCuO at both concentrations, and by ∼40% with μCuO, also at both concentrations, the difference among compounds was not statistically significant. Exposure to μCuO at both concentrations and nCu at 80 mg kg(-1) significantly reduced (p≤ 0.05) shoot elongation by 11% and 12.4%, respectively, compared with control. Only μCuO at 20 mg kg(-1) significantly reduced (26%) the relative chlorophyll content, compared with control. None of the treatments increased root Cu, but all of them, except μCuO at 20 mg kg(-1), significantly increased shoot Cu (p≤ 0.05). Micro and macro elements B, Zn, Mn, Ca, Mg, P, and S were significantly reduced in shoots (p≤ 0.05). Similar results were observed in roots. These results showed that Cu-based NPs/compounds depress nutrient element accumulation in cilantro, which could impact human nutrition.

Effects of uncoated and citric acid coated cerium oxide nanoparticles, bulk cerium oxide, cerium acetate, and citric acid on tomato plants

Little is known about the physiological and biochemical responses of plants exposed to surface modified nanomaterials. In this study, tomato (Solanum lycopersicum L.) plants were cultivated for 210days in potting soil amended with uncoated and citric acid coated cerium oxide nanoparticles (nCeO2, CA+nCeO2) bulk cerium oxide (bCeO2), and cerium acetate (CeAc). Millipore water (MPW), and citric acid (CA) were used as controls. Physiological and biochemical parameters were measured. At 500mg/kg, both the uncoated and CA+nCeO2 increased shoot length by ~9 and ~13%, respectively, while bCeO2 and CeAc decreased shoot length by ~48 and ~26%, respectively, compared with MPW (p≤0.05). Total chlorophyll, chlo-a, and chlo-b were significantly increased by CA+nCeO2 at 250mg/kg, but reduced by bCeO2 at 62.5mg/kg, compared with MPW. At 250 and 500mg/kg, nCeO2 increased Ce in roots by 10 and 7 times, compared to CA+nCeO2, but none of the treatments affected the Ce concentration in above ground tissues. Neither nCeO2 nor CA+nCeO2 affected the homeostasis of nutrient elements in roots, stems, and leaves or catalase and ascorbate peroxidase in leaves. CeAc at 62.5 and 125mg/kg increased B (81%) and Fe (174%) in roots, while at 250 and 500mg/kg, increased Ca in stems (84% and 86%, respectively). On the other hand, bCeO2 at 62.5 increased Zn (152%) but reduced P (80%) in stems. Only nCeO2 at 62.5mg/kg produced higher total number of tomatoes, compared with control and the rest of the treatments. The surface coating reduced Ce uptake by roots but did not affect its translocation to the aboveground organs. In addition, there was no clear effect of surface coating on fruit production. To our knowledge, this is the first study comparing the effects of coated and uncoated nCeO2 on tomato plants.

Comparison of the effects of commercial coated and uncoated ZnO nanomaterials and Zn compounds in kidney bean (Phaseolus vulgaris) plants

Bean (Phaseolus vulgaris) plants were grown for 45 days in soil amended with either uncoated (Z-COTE®) and coated (Z-COTE HP1®) ZnO nanomaterials (NMs), bulk ZnO and ZnCl2, at 0-500mg/kg. At harvest, growth parameters, chlorophyll, and essential elements were determined. None of the treatments affected germination and pod production, and only ZnCl2 at 250 and 500mg/kg reduced relative chlorophyll content by 34% and 46%, respectively. While Z-COTE® did not produce phenotypic changes, Z-COTE HP1®, at all concentrations, increased root length (∼44%) and leaf length (∼13%) compared with control. Bulk ZnO reduced root length (53%) at 62.5mg/kg and ZnCl2 reduced leaf length (16%) at 125mg/kg. Z-COTE®, at 125mg/kg, increased Zn by 203%, 139%, and 76% in nodules, stems, and leaves, respectively; while at the same concentration, Z-COTE HP1® increased Zn by 89%, 97%, and 103% in roots, stems, and leaves, respectively. At 125mg/kg, Z-COTE HP1® increased root S (65%) and Mg (65%), while Z-COTE® increased stem B (122%) and Mn (73%). Bulk ZnO and ZnCl2 imposed more toxicity to kidney bean than the NMs, since they reduced root and leaf elongation, respectively, and the concentration of several essential elements in tissues.

Modulation of CuO nanoparticles toxicity to green pea (Pisum sativum Fabaceae) by the phytohormone indole-3-acetic acid

The response of plants to copper oxide nanoparticles (nano-CuO) in presence of exogenous phytohormones is unknown. In this study, green pea (Pisum sativum) plants were cultivated to full maturity in soil amended with nano-CuO (10-100nm, 74.3% Cu), bulk-CuO (bCuO, 100-10,000nm, 79.7% Cu), and CuCl2 at 50 and 100mg/kg and indole-3-acetic acid (IAA) at 10 and 100μM. Results showed that IAA at 10 and 100μM, averaged over all Cu treatments, reduced the number of plants by ~23% and ~34%, respectively. IAA at 10μM, nano-CuO at 50mg/kg, b-CuO at 50mg/kg, and CuCl2 at 100mg/kg reduced pod biomass by about 50%. Although some combinations of IAA, mainly at 100μM, with the Cu compounds altered nutrient accumulation in tissues, none of them affected pod elements. Conversely, without IAA, nano-CuO at 50mg/kg, increased pod Fe and Ni by 258% and 325%, respectively, while bCuO at 100mg/kg increased pod Ni by 275%, compared with control. With IAA at 10μM, nano-CuO (100mg/kg) and bCuO (50mg/kg) increased stem Cu by ~84% and ~78%. When IAA increased to 100μM, nano-CuO and bCuO reduced stem Ca by 32% and 37%, and Mg by ~35%. Results suggest that both the nano-CuO and bCuO could improve the nutritional quality of pea pods, while exogenous IAA combined with Cu-based compounds could impact green pea production since these treatments reduced the number of plants and pod biomass.

Nutritional quality of bean seeds harvested from plants grown in different soils amended with coated and uncoated zinc oxide nanomaterials

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.

Effects of Surface Coating on the Bioactivity of Metal-Based Engineered Nanoparticles: Lessons Learned from Higher Plants

Characteristics such as size, surface-to-volume ratio, and surface chemistry, among others, convey uniqueness to engineering nanoparticles (ENPs). The surface chemistry determines the stability and aggregation of ENPs and also constrains their applications, environmental fate, and interaction with living organisms. To avoid aggregation and improve stabilization, the surface chemistry of numerous ENPs has been modified through coating with several agents. However, the coating also changes their biointeractions. In this chapter we discuss literature concerning the uptake, translocation, accumulation, and physiological effects of surface-coated ENPs in economically important plants. We discussed existing information based on the type of ENP, coating agent, and species of plant. Negative and positive effects are discussed.

Different forms of copper and kinetin impacted element accumulation and macromolecule contents in kidney bean (Phaseolus vulgaris) seeds

The relationship between engineered nanomaterials and plant biostimulants is unclear. In this study, kidney bean (Phaseolus vulgaris) plants were grown to maturity (90 days) in soil amended with nano copper (nCu), bulk copper (bCu), or copper chloride (CuCl2) at 0, 50, or 100 mg kg-1, then watered with 0, 10, or 100 μM of kinetin (KN). Seeds were harvested and analyzed via ICP-OES and biochemical assays. While seed production was largely unaffected, nutritional value was significantly impacted. Accumulation of Cu was enhanced by 5-10% from controls by Cu-based treatments. Fe was the only macro/microelement significantly altered by nCu, which was ~29% lower than seeds from untreated plants. All forms of Cu combined with 10 μM KN reduced Mg from 9 to 12%. Application of KN plus bCu or CuCl2 elevated concentrations of Mn (31-41%) and S (19-22%), respectively. Protein content of seeds was stimulated (11-12%) by bCu, on average, and depressed by CuCl2 + KN (up to 22%). Variations in sugar and starch content were insignificant, compared to controls. Our results indicate that the interaction Cu × KN significantly altered the nutritional value of common beans, which has potential implications to agricultural practices incorporating Cu as either a pesticide or fertilizer.

Finding the conditions for the beneficial use of ZnO nanoparticles towards plants-A review

Zinc oxide nanoparticles (ZnO NPs) have a wide range of applications in cosmetics, electrical, and optical industries. The wide range of applications of ZnO NPs, especially in personal care products, suggest they can reach major environmental matrices causing unforeseen effects. Recent literature has shown conflicting findings regarding the beneficial or detrimental effects of ZnO NPs towards terrestrial biota. In this review we carried out a comprehensive survey about beneficial, as well as detrimental aspects, of the ZnO NPs exposure toward various terrestrial plants. A careful scrutiny of the literature indicates that at low concentrations (about 50 mg/kg), ZnO NPs have beneficial effects on plants. Conversely, at concentrations above 500 mg/kg they may have detrimental effects, unless there is a deficiency of Zn in the growing medium. This review also remarks the critical role of the biotic and abiotic factors that may elevate or ameliorate the impact of ZnO NPs in terrestrial plants.

Copper oxide nanoparticles and bulk copper oxide, combined with indole-3-acetic acid, alter aluminum, boron, and iron in Pisum sativum seeds

The interaction of CuO nanoparticles (nCuO), a potential nanopesticide, with the growth hormone indole-3-acetic acid (IAA) is not well understood. This study aimed to evaluate the nutritional components in seeds of green pea (Pisum sativum) cultivated in soil amended with nCuO at 50 or 100mgkg-1, with/without IAA at 10 or 100μM. Similar treatments including bulk CuO (bCuO) and CuCl2 were set as controls. Bulk CuO at 50mgkg-1 reduced seed yield (52%), compared with control. Bulk CuO at 50mgkg-1 and nCuO at 100mgkg-1, plus IAA at 100μM, increased iron in seeds (41 and 42%, respectively), while nCuO at 50mgkg-1, plus IAA at 100μM reduced boron (80%, respect to control and 63%, respect to IAA at 100μM). IAA, at 10μM increased seed protein (33%), compared with control (p≤0.05). At both concentrations IAA increased sugar in seeds (20%). Overall, nCuO, plus IAA at 10μM, does not affect the production or nutritional quality of green pea seeds.

Biophysical Methods of Detection and Quantification of Uptake, Translocation, and Accumulation of Nanoparticles

Manufactured nanomaterials (MNMs) are more frequently found in consumer products as well as in industrial and agricultural applications. The high volume of production, use, and disposal of MNM-containing wastes increase the probability of release of these products to the environment. An ever-increasing number of articles have shown that MNMs impact plants and other organisms in different ways. In this chapter, we discuss the biophysical methods currently used to measure the uptake, translocation, accumulation, and speciation of MNMs within plants. We included methods used to analyze plants exposed to carbon-based and metal-based MNMs. Advantages and disadvantages of each analytical technique are discussed.