Transformation of 14 C-Labeled Graphene to 14 CO2 in the Shoots of a Rice Plant.

This study focused on using carbon-14-labeled few-layer graphene (FLG) to determine its uptake, distribution, transformation, and depuration in rice plants. After 7 d hydroponic exposure to FLG suspension at 250 μg L-1 , roots accumulated 694.8 mg kg-1 graphene and shoots had 53.7 mg kg-1 graphene from intra-plant translocation. FLG could likely pass through the cell wall and membrane and enter the chloroplast in the shoots. After 14 days of depuration, only about 15 % of the accumulated FLG were eliminated into the depuration solution with about 70 % of graphene retained in the plants. About 9 % of the accumulated FLG was degraded to 14 CO2 and proposed that reaction with OH. in the leaves may likely contribute to the degradation of FLG, which had structural defects. These findings have an important impact on the long-term environmental fate of graphene-related materials in soil-plant systems.