ABSTRACT
The uptake of selenium (Se) by plants has received considerable attention since the 1930s, when toxic effects where reported in animals that had consumed forage containing selenium in amounts greater than 1 mg Se/kg dry matter (Robinson, 1933; Beath et al.,1934). Selenium once was considered a highly toxic carcinogenic element and was used primarily for industrial purposes (Nelson et al.,1943; Volgary and Tscherkes,1967). This perception changed in 1957, when Se was found to prevent dietary hepatic necrosis in rats (Schwarz and Foltz, 1957). Research on Se uptake by plants has emphasized plant species considered as Se accumulators (Brown and Shrift, 1982). Selenium deficiency and the importance of Se in nutritional and metabolic functions in lifestock (Paterson et al., 1957; Schwarz and Foltz, 1957; Drake et al.,1960; Sharman, 1960; Tagwerker, 1960) became the focus of widespread interest. In the 1980s, the discovery of high concentrations of Se in agricultural drainwater (Presser and Barnes, 1984) and the resultant embryonic mortality of waterfowl at Kesterson Reservoir, Merced County, California (Ohlendorf et al., 1986a, 1986b), renewed interest in the environmental toxicity of Se and in food chain contamination. Recent research on plant uptake of Se has placed greater emphasis on Se nonaccumulators, including pasture plants, vegetable and cereal crops, and naturally established field plants. It is not the purpose of this chapter to review extensively the literature on uptake of Se by plants, but rather to focus on the recent research on Se uptake and accumulation by crop and grassland plant species.
