Impacts of cuprous oxide nanoparticles on wheat root morphology and genotoxicity

To explore the ecotoxicity of Cu₂O nanoparticles (NPs) on plant roots, the effects of Cu₂O-NPs with different concentrations of 10, 50, 100 and 200 mg·L^-1 on the seedling growth, root morphology, and cytogenetic toxicity of wheat 'Zhoumai 18' (Triticum aestivum Zhoumai 18) were examined in a hydroponic experiment. The results showed that Cu₂O-NPs inhibited the growth of wheat seedlings. Cu₂O-NPs reduced root and shoot lengths, fresh weights of shoot and root, root relative activity and ratio of root to shoot of wheat seedlings, but increased primary root number. Furthermore, with the increases of Cu₂O-NPs concentrations, the root elongation zone shortened and the root became hard and brittle, while the average diameter of roots increased. Under the concentration of 100 mg·L^-1 Cu₂O-NPs, the mitotic index significantly decreased, and vacuolization, plasma membrane detachment, chromosomal abnormality occurred in the root tip cell. In conclusion, Cu₂O-NPs are genotoxic to wheat seedlings, with consequences on the growth and development of wheat seedlings and root morphology.