Reproductive, Cellular, and Anatomical Alterations in Pistia stratiotes L. Plants Exposed to Cadmium

We evaluated the toxic effects of cadmi- um (Cd) on reproduction, the mitotic cycle, and on the root and leaf anatomy of Pistia stratiotes. Reductions in reproductive structures, symptoms of toxicity, and abnormalities in the cell cycle were noted in plants submitted to the highest Cd concentrations. The effects of the highest concen- trations of cadmium could also be observed in the thickening of the epidermis, exoderm, and endo- derm of the roots and by reductions in the number of crystalline idioblasts. Furthermore, decreases in the percentages of aerenchyma in the leaf blades and increases in the Carlquist vulnerability indexes of plants exposed to the highest concentrations of Cd were observed. The phytotoxicity of cadmium was quite evident in P. stratiotes, and it could thus be used as a bioindicator species as it was also tolerant of that pollutant.