Phytotoxicity and accumulation of copper oxide nanoparticles to the Cu-tolerant plantElsholtzia splendens

Abstract

The release of nanoparticles (NPs) to the environment poses an increasing potential threat to biological systems. This study investigated the phytotoxicity and accumulation of copper oxide (CuO) NPs to Elsholtzia splendens (a Cu-tolerant plant) under hydroponic conditions. The 50% effective concentration (EC50) of CuO NPs to E. splendens was about 480 mg/L, implying the tolerance of E. splendens to CuO NPs. The Cu content in the shoots treated with 1000 mg/L CuO NPs was much higher than those exposed to the comparable 0.5 mg/L soluble Cu and CuO bulk particles. CuO NPs-like deposits were found in the root cells and leaf cells. Cu K-edge X-ray absorption near-edge structure analysis further revealed that the accumulated Cu species existed predominantly as CuO NPs in the plant tissues. All these results suggested that CuO NPs can be absorbed by the roots and translocated to the shoots in E. splendens.

Copper oxide nanoparticle toxicity in mung bean (Vigna radiata L.) seedlings: physiological and molecular level responses of in vitro grown plants

“…As compared to shoot growth, root growth was significantly affected after treatment with even low concentrations of CuONPs. In accordance with our results, Shaw and Hossain (2013) and Shi et al (2014) has also reported that exposure CuONPs reduced root growth in rice and Elsholtzia splendens. Significant reduction in root development has also been reported from different plant species upon exposure to various types of MONPs (Lin and Xing 2008;Asli and Neumann 2009;Wang et al 2012).…”

“…Moreover, in accordance with the present study, Wang et al (2012) has also reported the uptake and translocation of CuONPs in wheat seedlings through the roots to shoots via xylem and shoots to roots via phloem. Shi et al (2014) proposed that once inside the plant tissues, the dissolution of CuONPs might be promoted due to the pH reduction and the interaction with organic acids and proteins in plant tissues and cells. The uptake and bioaccumulation of CuONPs has also been reported previously in mung bean plants by Lee et al (2008).…”

A Mechanistic Study on the Toxic Effect of Copper Oxide Nanoparticles in Soybean (Glycine max L.) Root Development and Lignification of Root Cells

“…However, higher exposure concentrations of CuONPs might have resulted in the excess presence of Cu in soybean roots leading to adverse effects on plant development as discussed below. Shi et al [26] have also reported that the Cu content in Elshotzia splendens exposed to 1,000 mg/L of CuONPs was much higher than those exposed to the comparable 0.5 mg/L of soluble Cu and copper oxide bulk particles. They concluded that the phytotoxicity was due to CuONPs exposure and not from soluble Cu in E. splendens.…”

“…Previous studies in maize (Zea mays) seedlings have proved that the uptake and translocation of CuONPs occurs through the roots to shoots via xylem and shoots to roots via phloem [27]. Moreover, Shi et al [26] reported that once inside the plant cells, the dissolution of CuONPs are promoted due to the reduced pH and by their interaction with organic acids and proteins inside the plant tissues. In accordance with earlier reports, metal (Cu) content analysis provided evidence for the presence of significantly high Cu content in roots of CuONP-exposed soybean seedlings.…”

Interactions between salt marsh plants and Cu nanoparticles – Effects on metal uptake and phytoremediation processes

“…So, plants can uptake the metal either from the dissolved fraction of the NP or uptake the NP itself. For instance, in sand-grown wheat, 58% of accumulated copper inside the shoots was attributable to CuO NPs (Dimkpa et al, 2013) and CuO NPs could also be absorbed by the roots and translocated to the shoots of Elsholtzia splendens (Shi et al, 2014). And in the duckweed Landoltia punctata, CuO NPs were found to be more toxic than ionic Cu due to the uptake of CuO NPs by the fronds (Shi et al, 2011).…”