Evaluation de la toxicité du cadmium sur deux fabaceae (phaseolus vulgaris et vicia faba) : étude des paramètres morphologiques, physiologiques, biochimiques, et anatomiques

Abstract

Among pollutants generated by human activities, heavy metals; of particular concern for environment and public health include Chromium, Lead, and Cadmium. Cadmium (Cd) is one of the most important elements due to its high mobility and its toxicity to plants. Our study aims to evaluate effect of cadmium on biometric, biochemical and physiological aspects, anatomical changes and phenolic compounds content of two plants Phaseolus vulgaris L. and Vicia faba L. seedlings are exposed to increasing concentrations of Cd: 0.25; 0.5 and 1 g.l¡¥1 for 21 days. Results obtained show that cadmium considerably decreases seed germination percentage, embryonic radical elongation, dry weight of plants, stem / root length and leaves and lateral roots number. At the same time, a decrease in chlorophyll and protein content is observed with all treatments for two plants; however, sugar and proline content increased significantly with 1 g.l¡¥1 of Cd. Total polyphenols content increased by approximately 43% and 32% in aerial and underground part respectively in Phaseolus vulgaris , and 43% and 39% in Vicia faba. Flavonoids, flavonols, hydrolyzable tannins and condensed tannins showed a significant increase with the highest concentration of cadmium. Cadmium has also altered roots and stems anatomy of plants; a decrease in number and size of xylem vessels and a delay in xylem differentiation were observed