Manganese (Mn) is an important microelement for the mineral
nutrition
of plants, but it is not effectively absorbed from the soil and mineral
salts added thereto and can also be toxic in high concentrations.
Mn nanoparticles (NPs) are less toxic, more effective, and economical
than Mn salts due to their nanosize. This article critically reviews
the current publications on Mn NPs, focusing on their effects on plant
health, growth, and stress tolerance, and explaining possible mechanisms
of their effects. This review also provides basic information and
examples of chemical, physical, and ecological (“green”)
methods for the synthesis of Mn NPs. It has been shown that the protective
effect of Mn NPs is associated with their antioxidant activity, activation
of systemic acquired resistance (SAR), and pronounced antimicrobial
activity against phytopathogens. In conclusion, Mn NPs are promising
agents for agriculture, but their effects on gene expression and plant
microbiome require further research.