Selenium-Containing Nanostructures: Synthesis, Properties, and Agrochemical Aspects of Application (Review)

Selenium is an essential trace mineral for plants. It is required for redox processes in cells, the synthesis of necessary compounds, and resistance against stresses of various nature. Interest in the use of nanoscale selenium for plant treatment is now increasing due to both a deficiency of selenium in soils and the toxicity of selenium compounds. This review discusses in detail the approaches for the synthesis of selenium nanoparticles: physical and chemical methods, as well as the use of living organisms (plants, bacteria, and fungi). The latter approach to nanoparticle synthesis has been gaining popularity in recent years due to the variety of reducing enzymes in organisms. In general, the effect of nanoselenium on plants depends on the size of nanoparticles and on the concentration applied. Available research demonstrates the positive effect of nanoselenium on plant viability and the resistance against stress. It is assumed that this effect is associated with (i) an increase in the intensity of photosynthesis, (ii) a change in the fatty acid profile of lipids, (iii) a decrease in lipid peroxidation, (iv) an increase in the content of essential organic compounds in plant tissues, as well as (v) an increase in the activity of antioxidant enzymes as a result of the influence of selenium nanoparticles.