Nanomaterials in plant systems: Smart advances related to water uptake and transport involving aquaporins

The application of nanoparticles (NPs) has been shown to be a very effective technology for increasing plant yield. Their use in agriculture has been associated with the reduction of fertilization, but their effectiveness depends on the concentrations applied, physiochemical properties, and plant species. Nevertheless, one of the most common reported effects, independently on the type of NPs, is their activation of aquaporin expression. Also, they work prominently when plants are growing under abiotic stress, conferring a potential benefit for the reduction of stress symptoms and agricultural losses in relation to increased water uptake and transport. In this article, we review the results obtained with different nanoparticles in plants, focusing the attention on their effect as biostimulants when plants were grown under abiotic stress conditions. Also, the mechanism of action as activating aquaporins expression are related with the different studied nanoparticles.