Effects of Graphene Oxide on Germination and Early Growth of Plants

Owing to its excellent material properties such as large surface area and superb mechanical and thermal characteristics, graphene oxide (GO) is likely to be applied in a variety of environmental fields. These applications may lead to the entrance of GO in terrestrial ecosystems, but there is little research regarding the impact of GO on plants upon such entrances. To analyze the effects of GO on the germination and growth of various plants, the changes in lettuce, radish, perennial ryegrass, alfalfa, and cucumber seeds under GO treatment was studied. Germination rate and growth were analyzed after the seeds were exposed to GO at 0, 0.2, 0.4, 0.8, and 1.6 mg ml^-1. For lettuce, the germination rate decreased with GO concentration. However, no significant effects were observed on the germination rate of other plants. On the other hand, the growth of lettuce, alfalfa, and radish decreased under GO treatment. For example, at 1.6 mg ml^-1 of GO, the length of shoot and root of lettuce was shortened by 87% and 86%, respectively. Such results indicate that the germination and early growth of plants can be negatively affected in a species-specific manner under high concentrations of GO. Hence, we anticipate that our results may assist in supplementing the legal regulations for the proper disposal of nanomaterials.