Résumé:
Lead is one of the most toxic heavy metals; it causes considerable damage on activity and biological development of living things. Its distribution across the various compartments of the environment remains largely related to human action. On plants the harmful effects of this pollutant can express the root level and air level, they are characterized by symptoms seen on morphological and physiological levels detectable by analysis at laboratory. This study is to monitor the behavior of the bean (Vicia faba L.) under lead stress. This plant is used as a model in eco-toxicology studies with its high biomass and its short growth cycle. For the realization of our work, we exposed the plant bean (variety Sidi Aich) at different doses of lead (0, 50, 100, 200, 500, 1000 and 2000 ppm) in the form of Pb nitrate (NO3) 2 these doses were applied to the growth substrate before transplanting the seeds. Several physiological order parameters were tested throughout the experiment to study the behavior of the treated plants deal with this stress. The found results showed significant reductions for all measured parameters, the chlorophyll pigment content and soluble sugar content in leaves are the most affected by the increase of lead dose parameters applied in the culture substrate. These results suggest that the presence of lead in the environment modifies the operation and the normal development of plants by internal disturbances on the physiological and biochemical level.
