Effect of ZnO Nanoparticles on Medicago Sativa at the Germination Stage

Phytotoxicity of manufactured nanoparticles in plants has received increasing attention. However, little information is available regarding the sensitive factor of Medicago sativa exposed to ZnO nanoparticles. The results showed ZnO nanoparticles had clearly effect on shoot length, shoot weight, shoot diameter, root/shoot ratio, root length, root weight, root diameter, root activity and mitotic index of Medicago sativa. Only root activity increased with the increasing concentration of ZnO nanoparticles. Principal component analysis showed root activity had a maximum absolute value in the first principal component, which indicated root activity was the key factor contributed to the variance. Therefore, root activity of Medicago sativa may serve as potential biomarker to indicate the pollution of ZnO nanoparticles.