Accumulation and Phytotoxicity of Engineered Nanoparticles toCucurbita Pepo

Abstract

The effect of bulk and engineered nanoparticle (NP) Ag, Au, Cu, Si, and C at 250 and 750 mg/L on zucchini biomass, transpiration, and element content was determined. The pH of bulk and NP solutions prior to plant growth frequently differed. Nanoparticle Cu solution pH was significantly higher than bulk Cu, whereas for Ag and C, the NPs had significantly lower pH. Plants were unaffected by Au, regardless of particle size or concentration. NP Ag reduced plant biomass and transpiration by 49-91% compared to equivalent bulk Ag. NP Si at 750 mg/L reduced plant growth and transpiration by 30-51% relative to bulk Si. Bulk and NP Cu were phytotoxic but much of the effect was alleviated by humic acid. The shoot Ag and Cu content did not differ based on particle size or concentration. The accumulation of bulk Au was greater than the NP, but humic acid increased the accumulation of NP and bulk Au by 5.6-fold and 80%, respectively. The uptake of NP Si was 5.6-6.5-fold greater than observed with the bulk element. These findings show that the NPs may have unique phytotoxicity or accumulation patterns and that solution properties can significantly impact particle fate and effects.

Interactions between nanoparticles and plants: phytotoxicity and defense mechanisms

“…TiO 2 NPs could significantly improve the germination rate of seeds; however, bulk TiO 2 can have inhibitory effects on seed germination. Similar results were observed in Feizi et al (2013) and Hawthorne et al (2012). Because of the high reactivity of small materials, NPs usually show greater toxicity than the same material of larger size (Oberdürster 2000).…”

“…However, there was no obvious discrepancy in the MDA level among control, 25 nm CeO 2 and its bulk counterpart treatment. Other reports have studied the effects of size and shape of NPs on various plant species as well (Hawthorne et al 2012;Syu et al 2014). In addition, demonstrated that plant responses to CeO 2 exposure varied with particle sizes and the growth stages of plants.…”

Bioavailability, Toxicity, and Fate of Manufactured Nanomaterials in Terrestrial Ecosystems

“…Larue et al (2012) reported no impact on plant development as a result of root exposure to MWCNT. Hawthorne et al (2012) reported no effect of fullerenes on zucchini biomass or transpiration at concentrations of up to 750 mg L À1 .…”

“…At 100 mg L À1 , there was complete disintegration of cell walls in most of the cells. Hawthorne et al (2012) exposed zucchini plants to Ag MNM and reported concentrationdependent reduction in biomass and transpiration starting at 250 mg L À1 . Toxicity was alleviated by addition of humic acid.…”

Application Of Nanotechnology In Agriculture And Food Industry, Its Prospects And Risks

“…The treatment with CuNPs resulted in significant reduction of growth and transpiration rate of Cucurbita pepo plants relative to untreated controls [109,110]. In Cucumis sativus seedlings CuO NPs were found to adhere to the root cell wall [111], and a significant increase in superoxide dismutase, catalase and peroxidase activities at CuO NPs application was observed [111].…”