|ZAMBRANO, M.C. - University Of Science And Technology Of China|
|YUAN, L. - Jiangsu University|
|YIN, X. - Jiangsu University|
Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 3/15/2017
Publication Date: N/A
Technical Abstract: Selenium hyperaccumulator plants like Stanleya pinnata, Astragalus bisulcatus and the newly discovered Se-accumulator Cardamine hupingshanensis may play an important role in the Se cycle from soil to plant to human in China. Se-hyperaccumulators can be used for agromining or for phytoremediation of Se, as well as for their application to Se-deficient soils in Se-biofortification strategies. Biofortification has exerted valuable efforts in enriching edible crop tissues with essential elements like iron (Fe), zinc (Zn), and/or selenium (Se) within crops (e.g. golden rice, cassava), as well as with nutraceutical compounds (e.g. antioxidants, carotenes, phenolics). The success of biofortification relies not only on promoting the accumulation of essential nutrients, but also on the more efficient bioavailability and assimilation of the nutrient by humans or animals. The agricultural-based strategy focuses on adding a Se source, e.g. inorganic Se, to produce Se-enriched food crops that will contribute to a greater Se intake in Se deficient communities. An alternative source to adding inorganic Se fertilizers is the application of plant tissue from Se-hyperaccumulator plant species (after harvest and milling) to the soil as a green Se-biofertilizer. This chapter will focus mainly on three Se-hyperaccumulator plant species and their potential use in agromining (extracting Se from the soil) and their use as a green Se-biofertilizer in a Se biofortification strategy. Stanleya pinnata, Astragalus bisulcatus and Cardamine hupingshanensis are suggested plant species for use in agromining high Se soils due to their ability to extract excessive amounts of Se from soil and accumulate Se to high concentrations. Several studies have shown that Se-hyperaccumulators accumulate between 2,000 to 10,000 µg Se g-1 DW on seleniferous soils (2 to 10 µg Se g-1) without suffering toxicity, while a non Se-accumulator plant will accumulate two orders of magnitude less Se (e.g. 25 µg Se g-1). Economically speaking, the market price for certain elements will depend on their annual yield per unit area (amount of the element/biomass produced), as well as the distribution and concentration of the element, e.g, Se, in a particular geographical area. The economics related to Se-hyperaccumulators to agromine for Se showed that the Se price per metric ton (annual yield per unit area) is relatively high (US $52,000). Another important feature that promotes the use of agromining Se is that hyperaccumulators are grown in Se-laden soils, which generally are of poor quality and would not support growing food crops. A drawback from using plants to agromine Se is that the percentage of Se removed seasonally will not be constant or predictable due to variable soil and environmental conditions, and consequently, Se concentrations in plant tissues will likely vary. Assuming high-Se soils are available, selecting, growing and utilizing a Se-hyperaccumulator species for agromining should be part of an agronomic strategy to provide growers with an additional organic source of Se, to sell as Se-biofertilizer for Se biofortification.