Toxic Effect of Multiwalled Carbon Nanotubes on Lettuce (Lactuca Sativa)

18 Introduction The multiwalled carbon nanotubes (MWNTs) are built by rolled graphene sheets as one type of nanoparticles composed by extensive sp carbon atoms. The diameter up to tens of nanometer and length vary substantially up to tens of micrometer [1]. Rising interest among scientists and industrialists are related to their extraordinary properties in mechanical, electronic and biomedical applications [2]. Recently by the large production of MWNTs, it may have potential release, environmental fate and ecological risk which correlated with plant species, type of media, treatment system, dose, exposure time, and properties of carbon nanotubes [3, 4]. Consequently, it deserves further attention. Instead of preliminary screening of several plants species as previously reported [5], we further investigate lettuce (Lactuca sativa) regarding the potential effect of MWNTs on plants conducted under hydroponic conditions. Concentration of MWNTs and CB used in this study is varied by 0, 125, 250, 500 and 1000 mg/L. It is important to show the significant effect of MWNTs on the seedling stage of lettuce for the understanding of toxic symptoms on root and leaves. In this report we also identified the reactive oxygen species (ROS) which may responsible for the phytotoxicity of MWNTs. Toxic Effect of Multiwalled Carbon Nanotubes on Lettuce (Lactuca Sativa)