Cd accumulation abilities of annual alfalfa (Medicago scutellata L.) by humic acid and growth promoting bacteria association

This experiment was carried out to study the effect of humic acid and growth promoting bacteria on uptake of cadmium heavy metal by annual alfalfa (Medicago scutellata L.). The experiment was arranged in pot experiment conditions in Isfahan, Iran in 2011. A factorial design was used based on completely randomized block design with four replications. Experimental treatments were humic acid and growth promoting bacteria. Biofertilizers used in the experiment were bacterial species Azotobacter chroococcum, Azospirillum lipoferum, and Pseudomonas putida in a mixture form and Glomus intraradices was used as mycorrhiza fungi. Cadmium heavy metal was applied at 0, 40, and 80 mg kg^-1 soil cadmium chloride (CdCl_2) levels. Root and shoot cadmium concentrations and translocation factor were measured in the plants under study. The results suggested that there were significant differences between treatment levels and their interactions for all measured characteristics. A significant trend in cadmium accumulation in root and shoot organs were observed with increasing in the cadmium concentration.