Selenium and its Role in Higher Plants

Selenium (Se) is a naturally occurring metalloid element which occurs nearly in all environments in the universe. The common sources of Se in earth crust occurs in association with sulfide minerals as metal selenide whereas, it is rarely seen in elemental form (Se0). Furthermore, Se is considered a finite and non-renewable resource on earth, and has been found to be an essential element for humans, animals, micro-organisms and some other eukaryotes; but as yet its essentiality to plants is in dispute. Thus, plants vary considerably in their physiological and biochemical response to Se. Therefore, this review focuses on of the physiological importance of Se for higher plants, especially plant growth, uptake, transport, metabolism and interaction of selenium with other minerals. Biogeochemistry of Se, its relationship with S, application of Se-containing fertilizers, Se in edible plants and finally, red elemental Se nanoparticles in higher plants will be highlighted.