Ameliorative Effects of Biochar for Cadmium Stress on Bean (<i>Phaseolus vulgaris</i> L.) Growth

In order to investigate the changes in the morphological and biochemical characteristics of bean plants in response to biochar treatment under cadmium (Cd) stress, a pot experiment was conducted in a greenhouse. Bean plants were subjected to different amounts of Cd (0, 100, 150 and 200 mg kg−1) and biochar applied at different doses (0, 2.5 and 5%). Under Cd stress, the growth and development of bean seedlings were remarkably inhibited, whereas the biochar treatment could effectively improve the heavy metal tolerance of bean seedlings. Cd stress caused an increase in the hydrogen peroxide (H2O2), malondialdehyde (MDA), proline and sucrose content, catalase (CAT), peroxidase (POD) and superoxide dismutase (SOD) activity of leaves. However, biochar treatments reduced the CAT, POD and SOD activity of bean seedlings. Growing beans on Cd medium led to a significant reduction in plant nutrient element content. However, biochar amendment to the soil elevated the plant nutrient element content compared to untreated soil. Cd content of the bean seedlings increased with increasing Cd doses. There was a sharp decrease in available concentration for Cd with the addition of biochar. In conclusion, biochar incorporation into the soil can alleviate the adverse impacts of Cd stress on the growth of bean seedlings