Ecological Aspects of Selenium Phytoremediation pp. 651-666
Authors: (Colin F. Quinn, Stormy D. Lindblom, Elizabeth A. H. Pilon-Smits, Biology Department, Colorado State University, Fort Collins, Colorado)
Abstract: Selenium is essential for many organisms but is toxic at elevated concentrations. The window between nutritious and toxic levels of Se is narrow, and both Se deficiency and toxicity are problems worldwide. For plants Se serves no known essential function, and uptake of Se by plants can lead to toxicity due to the similarity of Se to sulfur (S) and the incorporation of Se into S proteins. However, many plants readily take up Se and can benefit from increased Se due to increased growth and/or as an elemental defense. In relation to Se, plants can be classified into three categories: 1) non-Se accumulators 2) Se accumulators, and 3) Se hyperaccumulators. Non-Se accumulators do not accumulate Se, or only accumulate trace concentrations of Se, even when growing on seleniferous soils, Se accumulators can accumulate up to 1,000 mg Se kg-1 and Se hyperaccumulators accumulate upwards of 1,000 mg Se kg-1 and as much as 15,000 mg Se kg-1.