Evaluating the Effect of Organic Amendment and Growth-Promoting Bacteria in the Phytoremediation Process of Maize (Zea mays L.) under Cadmium Heavy Metal Stress

This experiment was performed to evaluate the effect of organic amendment and growth-promoting bacteria on phytoremediation of maize under cadmium (Cd) stress.

This experiment was performed in the form of factorial in a completely randomized design with 4 replications. Experimental factors were: 1- biochar as a soil organic amendment at two levels (non-application and application (20 g.kg-1 soil), 2- Pseudomonas putida at two levels (non-inoculation and inoculation of bacteria) and 3- heavy metal levels (0, 25, 50, 75 and 100 mg Cd. Kg-1 soil). 

Cadmium in all concentrations had reduced the dry weight of roots and shoots, while biochar application and bacterial inoculation increased these traits; when the maximum shoot dry weight (9.43 g per plant) was observed by biochar application and inoculation of Pseudomonas putida and no cadmium contamination, which increased 45.30% compared to the control. The highest amount of available cadmium in soil, roots and shoots were 23.29, 33.90 and 36.25 mg/kg, respectively, which all three were obtained in the concentration of 100 mg Cd/kg soil. The lowest amount of bioconcentration factor (0.75) and bioaccumulation factor (1.03) were related to the synergistic treatment of biochar and Pseudomonas putida at the concentration of 25 mg Cd/kg soil, which decreased up to 17.90 and 10.62% compared to the control, respectively.