Toxicity of selenium, application of selenium in fertilizers, selenium treatment of seeds, and selenium in edible parts of plants

Agronomic biofortification is one of the approaches which have been successfully adopted for improving the nutritional content of plant-based foods and is mainly focused on optimizing the application of mineral fertilizers and/or the improvement of the solubilization and mobilization of mineral elements in the soil. In general, mineral elements with a good dynamism in the soil and in the plant are good candidates for a prosperous agronomic biofortification. Selenium deficiency occurs in areas where soil Se is low, including parts of Europe, China, North America, Australia, New Zealand, and Southern Africa. Selenium toxicity occurs in areas where soil Se is naturally high, including areas of China, India, and the United States. Toxicity from naturally occurring Se may be intensified by irrigation of seleniferous soils, mining, and use of Se-rich fossil fuels. Then, management practices benefit from a thorough understanding of the mechanisms of plant Se uptake and the fate of Se in different plant species.