Effects of nanomaterials on seedling growth and disease control

Nanomaterials (NMs) are defined as materials with particle sizes between 1 and 100 nm. Some NMs have potential applications for plant growth promotion and disease control. In this study, silver nanoparticles (in forms of nano-scale silica platelets (AgNP/NSP)) and nano-scale silica platelets (NSP), together with micro/nano-sized calcium-silica composites (NCaSi) were tested for their effects on seedling growth and disease control. The results showed that AgNP/NSP inhibited growth of fungal pathogens. We also tested the effects of AgNP/NSP, NSP, and NCaSi on the growth of Chinese cabbage (baby pak choi), lettuce, tomato, and watermelon. AgNP/NSP reduced seed germination, root elongation and seedling growth of some test plants. However, NCaSi promoted tomato seedling growth and reduced diseases. NCaSi induced the production of some pathogenesis-related proteins and stress proteins, and also provided protection to plants against pathogens. Thus, application of NMs in plant disease management should be carefully evaluated.