ABSTRACT
Selenite and selenate are the major selenium (Se) species in soil that can be efficiently utilized by plants (Ellis & Salt 2003). Currently, the plant uptake mechanisms of selenite are not well understood. Some studies postulate that it enters the plant via a phosphate transporter (Li et al. 2008), and phosphate inhibits crop absorption of selenite. However, pot experiments have shown that phosphate application reduces Se content in crops through the dilution effect produced by crop growth, which did not seem to reduce Se accumulation (Mora et al. 2008). Since selenate and sulfate have the same mechanism of transport, there are significant inter-element antagonism effects between them. In contrast, field experiments showed that sulfate facilitated selenate uptake in wheat and buckwheat (Golob et al. 2016, Stroud et al. 2010). Therefore, there is a necessity to systematically clarify the regulatory effect of sulfur (S) on crop uptake of selenite and selenate in the production practice. It’s noteworthy that the bioavailability of Se in the human body is closely associated with Se speciation in the crops; therefore, the effect of S on Se speciation in the edible parts of crop should be of concern.
