ARS | Publication request: RADIOTRACER STUDY TO ELUCIDATE MECHANISMS OF ARSENIC HYPERACCUMULATION

Submitted to: American Society of Plant Biologists Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: March 19, 2004
Publication Date: July 24, 2004
Citation: Poynton, C.Y., Huang, J., Elless, M.P., Kochian, L.V., Blaylock, M.J. 2004. Radiotracer study to elucidate mechanisms of arsenic hyperaccumulation. American Society of Plant Biologists Annual Meeting. p. 30

Technical Abstract: The health risks of arsenic (As) are well documented, causing problems such as cancer and adversely affecting the immune system. Arsenic occurs naturally, but it has also been elevated anthropogenically, in particular from mining activities and from extensive application of As-containing herbicides and insecticides. The discovery of an As hyperaccumulating fern, Pteris vittata, raises the possibility of in-situ phytoremediation of contaminated soils and water. This fern can accumulate As in its fronds up to 21 g/kg after 6 weeks in soil contaminated with 0.5 g/kg As. It is likely that arsenate (but not arsenite) enters the fern through the phosphate uptake system and P-deficient ferns have previously been shown to have elevated levels of arsenate uptake. We have performed radioactive tracer studies, which allow high temporal and spatial resolution, to investigate the mechanisms of hyperaccumulation further. Root transport parameters, translocation and As speciation were studied in several Pteris species and compared with non-hyperaccumulating ferns. Translocation of As to the shoot in Pteris is very rapid and can be detected within 1 hour. Preliminary data suggests that there is a much greater difference in translocation from root to shoot between hyperaccumulating and non-hyperaccumulating species than there is in initial uptake into the roots. Ferns have also demonstrated the ability to remove greater than 99% of the As from an initial solution concentration of 200 mg/L, showing that they are effective at concentrations below the new national drinking water standard of 10 mg/L. The effect of source water quality and growth conditions on efficiency of As uptake have also been investigated in order to develop this technology.