Antimony Uptake and Speciation in Pteris Vittata.

Antimony (Sb) and arsenic (As) are analogs but their uptake and translocation mechanisms in plants are different. As-hyperaccumulator Pteris vittata converts AsV to AsIII and translocates most of it to the fronds, accumulating upto 2% in the fronds. This study examined SbIII and SbV uptake and speciation in P. vittata. Eight-month old P. vittata with 3-4 fronds were acclimatized in hydroponic in 0.2x strength Hoagland solution for 4 weeks and 0.5 mM CaCl₂ for 1 day. They were transferred to opaque containers with 1 L deionized water containing 1.6 or 8 mg/L SbIII or SbV for 24 h. The highest Sb concentration in the roots were 7,469 and 178 mg/ kg in the SbIII and SbV treatments respectively while there was only trace level of Sb in the fronds in all Sb treatments. P. vittata was 2 times more effective in taking up SbIII than SbV. Approximately 40% Sb in the growth media was present as SbV in the SbIII treatment, mostly from root exudates. P. vittata was ineffective in Sb translocation as most of the Sb was in the roots, which was significantly higher than other plants. P. vittata may have the potential to be used to phytostabilize Sb-contaminated soils.

Keywords: Antimony, Antimonite, Antimonate, Uptake, Speciation