FIGURE 4.

Effect of silver nanoparticles on PVY-Ros1 infectivity. (A) Pictures of representative leaves of tobacco plants mock-treated or sprayed with a preparation of silver nanoparticles in water at 100 and 1000 ppm, as indicated. Two days after treatment, leaves were mechanically inoculated with PVY-Ros1. Pictures were taken at 6 dpi with PVY-Ros1. (B) Histogram of the average number of infection foci per leaf of the six plants treated with silver nanoparticles, as indicated, and mechanically inoculated with PVY-Ros1 2 days later. Foci were quantified at 6 dpi with PVY-Ros1. Error bars represent the standard error median.