Toxicity of cadmium to wheat seedling roots in the presence of graphene oxide.

The effects of cadmium (Cd) on wheat seedlings in the presence of graphene oxide (GO) were investigated. Parameters evaluated include root morphology, microtubule protein content, cytochrome P450 activity, and the microcellular structure of wheat seedlings. Compared with treatments with Cd or GO in isolation, treatments combining GO and Cd inhibited the total root length, total root surface area, average root diameter, and number of root hairs. GO combined with Cd also increased cytochrome P450 activity and reduced tubulin content. Cotransport of GO-loading Cd entered root tissues and was then transported to the mesophyll cells; this, in turn, triggered damage to cellular structures, including the cell membranes and chloroplast, leading to root blockage and reduced respiratory efficiency, decreased effectiveness of water and nutrient absorption, and ultimate inhibition of wheat growth and development. These effects of GO exposure were also concentration-dependent. The results indicated that GO amplified the phytotoxicity of Cd in wheat seedling roots. Given the worldwide exposure of the environment to Cd contamination, careful consideration should be given to the effects of GO in combination with Cd in agricultural management.