Contribution à l'étude de l'action d'agents polluants sur des végétaux bioindicateurs

Abstract

The aim of this study could put in evidence the parameters determined the contamination of water course of the locality of Oued Athmenia with elements traces metallic and evaluated their potential effects on aquatic vegetable species. Four aquatic species; unicellular alga Chlorella sp. and macrophytes floating as well as emergent plants (Lemna minor, phragmites communis and Typha latifolia) were examined for their bioaccumulation of metallic elements. Beside this multitude of pollutants rejected in the environment, this species could or not adapted and therefore responded to the presence of these contaminants? Specially, that these contaminants can enter in competition with some ions necessary for their essential metabolites and replaced them at the active sites of several enzymes, which could cause decreased performance energetic, significant disturbance in their physiological and biochemical functioning. In the other hand, during this experimentation, the duck weed Lemna minor was more sensitive to the environment stress by the decline of their biomass, especially in the stations localized downstream. Chlorella sp. first link of the food chain, without root can be preserved of the influence of the substratum can reflected the quality of water course. Phragmites communis and Typha latifolia were demonstrated their capacity to accumulate high contents of these elements, but apparition of morphological (visual) symptoms of clorosis on above ground part. Finally, these species take into consideration in this study could give overall assessment of the quality of these water courses and the bioaccumulation of these elements in their organisms was an index of pollution. Beside this, these species were demonstrated their capacity to accumulate and to remove pollutants from this aquatic environment it’s very important to preserve this aquatic flora, seeing their function in this environment.