Quantitative evaluation of multi-wall carbon nanotube uptake by terrestrial plants

Abstract

The extent and mechanisms by which multi-wall carbon nanotubes (MWCNTs) are accumulated by terrestrial plant species is currently unknown. In this study, we successfully measured the MWCNTs content in different plant (Arabidopsis thaliana, rice, maize and soybean) using 14 C labeled MWCNTs. Quantitative relationships among the uptake amount of MWCNTs in different Arabidopsis tissues, the physiological (water loss, pigment content, and total protein content) and biochemical parameters (antioxidant enzyme activities) were further evaluated. Our results indicated that changes in biochemical parameters were much more sensitive than physiological parameters. The lowest CAT activities in the treatment with (1,3dinitrobenzene + MWCNTs) were only 0.13-fold of that in the 1,3-dinitrobenzene alone treatment, suggesting MWCNTs could alleviate the toxicity to Arabidopsis. Due to the toxicity caused by small polar aromatic organic molecules (SPAOMs), the MWCNTs uptake in leaf in the treatment with (2,4-dichlorophenol + MWCNTs) was only 0.07-fold relative to the MWCNTs alone treatment. Hydrodynamic diameter of MWCNTs in solution did not significantly affect MWCNTs uptake. Uptake models for MWCNTs into root and leaf tissue were constructed via stepwise multiple linear regression analysis. This study will provide important information for the accurate determination of risk associated with MWCNT exposure.

Various Physiological Response to Graphene Oxide and Amine-Functionalized Graphene Oxide in Wheat (Triticum aestivum)

“…A previous study investigated the uptake and translocation of C70 and MWCNTs in the rice plant and found C70 inside the plant root and simultaneously transported via transpiration and the evaporation of water, forming aggregation within the vascular system, while little MWCNTs were absorbed by root cells [ 46 ]. Conversely, MWCNTs are accumulated in Arabidopsis thaliana , Onobrychis arenaria , rice, maize and soybean, changing the biochemical and physiological/morphometric parameters [ 47 , 48 , 49 ]. Even, under salt stress, MWCNT can enter into broccoli cells with higher accumulation, inducing positive effects on plant growth as consequence of improved water uptake and increased net assimilation of CO 2 .…”

Microplastics and Nanoplastics in the Freshwater and Terrestrial Environment: A Review

“…The difference with flora as compared to fauna is that each plant's uptake varies depending on a multitude of factors: root volume, density and surface area, xylem volume, surface area and sap pH, transpiration, growth rate, water and lipid fractions and sorption potential, plasmalemma (bio-membrane) potential, tonoplast potential, pH of the cytoplasm and vacuoles [156]. The vast differences between plants make it difficult to pinpoint the impacts that nanoplastics may cause; however, some studies using engineered carbonaceous nanoparticles, similar in size, shape and surface functional groups to microplastics, have been documented in whole plants (i.e., rice (Oryza sativa) [157], maize (Zea mays), soybean (Glycine max) and thale cress (Arabidopsis thaliana) [158]) and thought to have entered by one of the following pathways: endocytosis through the plasmodesmata, ion transport channels, carrier proteins or aquaporins, and soil carbon or root exudate mediation [4]. However, very few studies have been conducted on the toxicity, stress and response of plants to nanoplastics.…”

Nanomaterials in Plants: A Review of Hazard and Applications in the Agri-Food Sector

“…In the event of uptake, translocation to leaves may be restricted by the Casparian strip, necessitating symplastic transport through cellular plasmodesmata to reach the xylem and phloem [4]. For both root and foliar exposures, NM uptake is highly dependent on the plant species and transpiration rate [9,11,20], and NM size [18,21], chemical composition [22,23], surface functionalization [24,25,26], age [27], and stability [28].…”