Graphene
oxide (GO) is considered to be an emerging environmental
pollutant with its inevitable release into the environment. Thus,
its potential environmental risks and biosafety are receiving increased
attention. In this study, Paeonia ostii was exposed
to GO under drought stress. The results demonstrated that GO prevented
soil water from evaporating due to its hydrophilic oxygen-containing
functional groups and did not change the soil pH. Moreover, GO treatment
resulted in lower increases in reactive oxygen species, relative electrical
conductivity and free proline content, and greater increases in the
antioxidant enzyme activities of P. ostii under drought
stress compared with those in the control. And under drought stress,
higher photosynthesis, more intact mesophyll cells and organelles
and open stomata were found in P. ostii under GO
treatment. Furthermore, GO treatment induced greater changes in the
expression patterns of genes required for lignin biosynthesis, photosynthesis-antenna
proteins, carbon fixation in photosynthetic organisms, and glyoxylate
and dicarboxylate metabolism. Additionally, GO did not accumulate
in P. ostii due to the soil environment and the electrostatic
repulsion between GO and the roots. GO did not have toxic effects
on P. ostii and was an effective soil water retention
agent; therefore, it could be economically beneficial for the production
of plants under drought stress.