MORPHOLOGIC ALTERATIONS IN Eichhornia crassipes (WATER HYACINTH) (Mart.) Solms-Laubach, DISPLAYED TO RAISED MERCURY CONCENTRATIONS

The objective of this work is to verify the possible morphologic changes observed in Eichhornia crassipes (water hyacinths) due to mercury, evaluating the toxic effects of this metal on the development of this species. The experiments were carried out during five days in dark bottles with 0,5 L of Hoagland and Arnon (1950) solution, with 1/4 of the original ionic force and pH 6.5, added of different levels of concentration of dihydrated mercury nitrate [Hg(NO3)(2). 2H(2)O]: 0.5; 2.5; 5.0 e 10.0 mg L-1, being each treatment carried out in triplicates. All treated individuals, except those of the control treatment, presented visual symptoms of toxicity and chlorosis, wrinkling and rolling up of the foliar blade and necrosis. The results showed that the higher the concentration of the metal in the solution the higher the proportion of injuries. The production of biomass was possibly affected by dosages of mercury, decreasing 5.4%, 9.2%, 9.0% and 14.2% when the doses of mercury were 0.5; 2.5; 5.0 and 10.0 mg L-1 respectively. Whereas the new mass of treatment control individuals increased 9.0%, approximately. The foliar injuries were not mortal until the ending of this experiment. It is suggested the development of anatomical physiological and chemical studies for the obtention of data that could make evident the phytoremediator potential of this species in order to be used and recommended for the removal of the mercury in aquatic environments.