Silver nanoparticles (AgNPs) are one of the most widely used nanoparticles involved in ecosystem. Silver nanoparticles were used in the preparation of new pesticide and insecticide formulations. However, the effect of AgNPs is on vascular plants is still unclear. In this paper the effect of Ag NPs (100nm) on germination, root elongation as well as nucleic acids and proteins contents of barley plant was evaluated. Our findings obviously indicate that germination percent was not affected after all treatments whereas seedling length, nucleic acids and proteins contents were highly affected after treatment with the higher concentration of nano particles (100 ppm) as compared to the control (untreated). Our investigations suggest that plant cells as an important marker of the ecosystems need to be included when evaluating the overall toxicological impact of the engineered nano-particles in the environment.