The effects of various platinum metal species on the water plant Eichhornia crassipes (MART.) Solms

Abstract

Eichhornia crassipes, the water hyacinth, has been grown in the presence of a number of complexes of the platinum group metals. In general those compounds which are taken up by the plants in larger quantities are the more toxic. The relative order of toxicities determined from visual appraisal and in terms of oxidation states, is Pt(II), Pd(II) > Ru(III) - Ru(II) - Ir(III) > Pt(IV) - Os(IV) >> Rh(III)). In most cases the metals are accumulated in the roots, and where the metal is translocated to the tops and this is associated with toxic symptoms. Root elongation and biomass studies confirm that Eichhornia is more tolerant to Rh(III) and Pt(IV) than to Pt(II). Treatment with a Rh and three Pt complexes produced little differences in the concentrations of Ca, Cu, Fe, Mn and Zn in treated plants compared with controls. Sequential extractions of tissue from plants treated with cis[Pt(NH3)2Cl2] showed that in the leaves and floats almost half the platinum is insoluble and associated with α-cellulose and lignin, 16% is removed by the enzyme pronase and can be considered to be associated with proteins or amino acids. In the roots, about a third of the Pt is insoluble and 9.5% is removed by pronase. More Pt in the roots appeared in the fraction containing water soluble low molecular weight materials. © 1994 Taylor and Francis Group, LLC.