Response of Pistia stratiotes to Heavy Metals (Cr, Ni, and Zn) and Phosphorous.

MUFARREGE, M. M.; HADAD, H. R.; MAINE, M. A.

ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY

Springer

Lugar: New Jersey; Año: 2010 vol. 58 p. 53 - 61

0090-4341

The effects of Cr, Ni, Zn and P exposure on the root anatomic structure, growth and chlorophyll a concentration of Pistia stratiotes L. were studied. Plastic aquaria containing 50 g of wet plants and 5 L of pond water added with the contaminant/s were disposed. The treatments were: 1) Cr, 2) Ni, 3) Zn, 4) P, 5) Cr+Ni+Zn, 6) Cr+Ni+Zn+P and 7) control. Contaminant additions were done 7 times. In each addition, concentrations of 1 mg of metals or 5 mg of P by liter of water were added. Chlorophyll a was an indicator more sensitive to Zn and Cr toxicity than the relative growth rate. Ni and Cr+Ni+Zn treatments were the most toxic ones, in which biomass and the root anatomical parameters (root length, cross-sectional areas (CSAs) of root, stele and metaxylem vessels) decreased significantly. The addition of P to the treatment with combined metals attenuated the decrease of plant growth and root length, and caused a significant increase of CSAs of total metaxylem vessels, suggesting that P increased tolerance of P. stratiotes to metals. This fact has important implications for the use of this macrophyte in constructed wetlands for industrial wastewater treatment.