For the radishes, twice as many lesions were induced in plants exposed to nanoparticles as were in those exposed to the larger particles. Additionally, the cellular uptake of copper from the nanoparticles was significantly greater than the uptake of copper from the larger particles. The DNA damage profiles for the ryegrasses differed from the radish profiles, indicating that nanoparticle-induced DNA damage is dependent on the plant species and on the nanoparticle concentration.
Finally, the researchers showed that cupric oxide nanoparticles had a significant effect on growth, stunting the development of both roots and shoots in all three plant species tested. The nanoparticle concentrations used in this study were higher than those likely to be encountered by plants under a typical soil exposure scenario.
"To our knowledge, this is first evidence that there could be a 'nano-based effect' for cupric oxide in the environment where size plays a role in the increased generation and accumulation of numerous mutagenic DNA lesions in plants," Nelson says.
Next up for Nelson and his colleagues is a similar study looking at the impact of titanium dioxide nanoparticlessuch as those used in many sunscreenson rice plants.
|Contact: Michael E. Newman|
National Institute of Standards and Technology (NIST)