Influence of nano-priming on seed germination and plant growth of forage and medicinal plants

Plant growth and development are vastly affected by different abiotic and biotic stresses. Seed priming is an effective tool for increasing seed germination and plant growth that will eventually increase productivity under different environmental conditions and stresses. Efficient seed germination promotes successful establishment and deep root system of plants. Among the different seed priming methods, nano-priming is more effective mainly because of its small size and unique physicochemical properties. Since plant species are physiologically different, they differ in their uptake of nanoparticles in nano-priming, and hence in their rate and manner of growth. Most previous studies have separately investigated the effect of nanomaterial on seed germination, growth, and development of one plant at a time. However, very few studies have reported nano-priming effects using different particles on seed germination and seedling growth of forage and medicinal plants together. Therefore, this review summarizes studies of nano-priming effects using various particles on seed germination and seedling growth of forage and medicinal plants. Furthermore, the effect of different nanoparticles on the most important characteristics of germination, morphology and physiology affecting the establishment, growth and production of these plants are reviewed. In general, nano-priming increased seed germination, seedling growth and development, vigor, rate of seedling emergence and subsequent performance in most of the medicinal and forage plants. While the use of nanoparticles enhanced environmental stress resistance of these plants, negative effects of nano-priming on seed germination, seedling and plant growth traits were observed. In addition, future research areas of focus are discussed briefly.