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

Abstract

An increasing number of investigations have been performed on the phytotoxicity of carbon-based nanomaterials duo to their extensive use in various fields. In the present study, we investigated the phytotoxicity of unfunctionalized graphene oxide (GO) and amine-functionalized graphene oxide (G-NH2) on wheat (Triticum aestivum) in the concentration range from 125 to 2000 μg/mL after 9 days of hydroponic culture. Our results found that the incubation with both nanomaterials did not affect the final seed germination rate, despite some influence in the initial stage. Transmission electron microscopy (TEM) observations indicated that exposure to GO at a high concentration (above 1000 μg/mL) resulted in a severe loss of morphology of seedlings, and a decrease in root length, shoot length and relative biomass, along with obvious damage to plant tissue structures (root, stem and leaf) when compared with the control. GO induced increased damage to root cells, which were determined by electrolyte leakage. Conversely, the plant growth was enhanced under G-NH2 exposure, and the root and stem lengths were increased by 19.27% and 19.61% at 2000 μg/mL, respectively. The plant tissue structures were not affected, and neither GO nor G-NH2 were observed to accumulate in the wheat plant root cells. The present investigations provide important information for evaluation of the environmental safety of GO and better understanding plant-nanoparticle interactions.

Effects of graphene on morphology, microstructure and transcriptomic profiling of Pinus tabuliformis Carr. roots

“…Studies on herbaceous plants have shown that graphene treatment can cause damage to the cell membrane [ 34 , 35 ]. The transmission electron microscopy images showed clear evidence of damage to the cell structure in the graphene treatment group relative to the CK ( Fig 3 ).…”

Dual Effect of Nanomaterials on Germination and Seedling Growth: Stimulation vs. Phytotoxicity

“…During the comparison of the effects of GO and amine-modified graphene (G-NH 2 ) it was found that at high concentrations (500, 100 or 2000 mg L −1 ), GO inhibited wheat germination and seedling growth, while the same doses of G-NH 2 exerted positive effects. The electrolite leakage of roots was increased by GO exposure supporting the toxic nature of this nanomaterial type [ 96 ]. According to Vochita et al [ 97 ], wheat seed germination was inhibited by a high dosage of GO (2000 mg L −1 ) and a slight reduction in root elongation was also observable at this concentration.…”

Phytotoxicity of Graphene Family Nanomaterials and Its Mechanisms: A Review

“…Graphene can be transferred from wheat roots to shoots and enter the cytoplasm and chloroplasts (Hu et al, 2014c); however, GO accumulation was not observed in the root cells of wheat (Chen et al, 2018a). Furthermore, GO did not accumulate in the seedlings of spinach and chive from if their seeds were treated with 50 mg/L GO (He et al, 2018).…”

“…Compared to graphene and GO, hydrated graphene ribbon (HGR) not only promoted the germination rate of aged seed, but also increased root differentiation; the disordered layer structures of HGR played a key role in this process (Hu and Zhou, 2014). The observations of Chen et al (2018a) showed that GO induced obvious toxic symptoms in wheat, while amine-functionalized GO was non-toxic and enhanced plant growth. They inferred that the introduction of amines could decrease the surface electrical resistivity of GO, creating higher electronic conductivity, and activating bioactivity in plant cells.…”