Transport of Ferrocyanide by Two Eucalypt Species and Sorghum

Abstract

The wastes from some industrial processes and the tailings from gold mining contain elevated concentrations of cyanide, which reacts with iron in the media to form iron cyanide complexes. This research examined the transport and possible metabolism of ferrocyanide by two native Australian trees, blue mallee and sugar gum, and by sorghum. Hydroponic studies using 15N-labeled ferrocyanide showed that both tree species transported ferrocyanide into roots and displayed significant increases in 15N enrichment and concentration with no evidence of phytotoxicity. A subsequent experiment with blue mallee and membrane-transport inhibitors showed that 15N enrichment was significantly inhibited in the presence of the protonophore carbonyl cyanide m-chlorophenylhydrazone, suggesting that ferrocyanide uptake is mediated partly by H+ -symporters. A study of the time dependence of 15N translocation showed a rapid equilibration of 15N from ferrocyanide in the root of blue mallee, accompanied by a slow increase in shoot 15N, suggestive of the metabolism of ferrocyanide in plant roots. A similar experiment with sorghum showed a more rapid translocation of 15N, suggesting that the transport and/or metabolism of ferrocyanide by roots of this species may differ. The results offer additional incentive for the use of these species as vegetative cover over cyanidation wastes and for cyanide phytoremediation.

Phytotoxicity of dimethyl sulfoxide (DMSO) to rice seedlings

“…XZX 45) with similar height and weight were transplanted to a pre-treatment solution containing 1 mM CaCl 2 ? 2 mM MES-Tris buffer (pH 6.0) for 4 h to clear the ions from cell wall space (Ebbs et al 2008), and then ten rice seedlings were transferred into a 50-ml Erlenmeyer flask filled with 50 mL modified ISO 8692 nutrient solution (Yu et al 2014a) with addition of 10 lM Fe-EDTA. The plants were first conditioned for 24 h to allow adaptation to the new environmental conditions.…”

Effects of inhibitors on ferricyanide uptake and assimilation by plants

“…channel blocker (Ebbs et al 2008). Na 3 VO 4 , HgCl 2 , and AgNO 3 are inhibitors of the ion transporting (Ebbs et al 2008;Zhang et al 2010). TEACl is an anion channel inhibitor (Zhang et al 2010).…”

“…Several cyanide-containing compounds have been detected in the environment, namely free cyanide, weak-acid dissociable cyanide, iron cyanides, and thiocyanate (Ebbs et al 2008). Of the iron cyanides detected, ferricyanide [Fe III (CN) 6 ] -3 is one of the most commonly found species (Mansfeldt et al 2004), which has a closer link to the presence of free cyanide (CN -and HCN) derived from both anthropogenic and natural sources (Ebbs et al 2010).…”

“…There is abundant literature showing that a number of biotic and abiotic factors, including pH, redox potential, the availability and quality of solar radiation, biological activity and community, and the presence of organic are activated in the fate and speciation of ferricyanide in the environment (Ghosh et al 2004;Rennert and Mansfeldt 2002;Yu et al 2011a, b). Indeed, dissociation of ferricyanide due to the changes in the physicochemical conditions shows significant concerns, although it is less toxic than free cyanide (Ebbs et al 2008;Zagury et al 2004).…”

“…Although direct evidence of the plant-mediated uptake and assimilation of ferricyanide is still under investigation, several studies have been conducted to clarify the possible biological transport and fate involved (Ebbs et al 2003(Ebbs et al , 2008Larsen and Trapp 2006;Samiotakis and Ebbs 2004;Yu and Gu 2010). Unlike botanical uptake of small neutral chemical species, ferricyanide is unable to move through biological membranes by simple diffusion due to its physical-chemical properties (Ebbs et al 2003;Federico and Giartosio 1983).…”