NEED FOR THE PROJECT Selenium (Se) is a chemical element with atomic number 34. It is a nonmetal with properties that are intermediate between the elements above and below in the periodic table. It is an important microelement, exists in small quantity in microorganisms, plants, animals and humans. It is an essential trace nutrient important to humans and most other animals and act as anti-aging, repairing cells, improving human immunity and preventing carcinogenesis but toxicity occurs when taken in large quantity. It is also a basic component of various enzymes such as glutathione peroxidase (GSH-Px) and thioredoxin reductase (TR), which involve in the antioxidant protection of cells (Rotruck et al., 1973; Birringer et al., 2002). Deficiency …show more content…
However, toxicity of Se came into limelight after the tragedy of Kesterson wild-life Refuge and Reservoir in San Joaquin Valley in California in 1980, which gave this element a worldwide concern (Winkel et al., 2012). Information of Se in plants is important because plants are the main dietary source for human beings and animals. Selenium resembles to sulfur in chemical properties, both have similar transporting and assimilating pathway taken up inside the plants. (Dumont et al., 2006). Certain species of plants require high levels of selenium to flourish and are considered indicators of high selenium content of the soil. The main Se indicator plants are prince's plume (Stanleya sp.), woody asters (Xylorhiza sp.), Astragalus species (including some locoweeds), and false goldenweed (Oonopsis sp.) (Gregory and Vadim, 2004). Inside the plants, Se is transported through sulfate transporters which are present in the plasma membrane of root cells. Through sulfur metabolic pathway it is assimilated to organic Se and volatilized as DMSe (Dimethylselenide) and DMDSe (Dimethyldiselenide) into atmosphere. ( Meetu and Shikha,