Phytotoxicity of heavy metals in Cynara cardunculus L. Growing in contaminated soil

The biological response of cardoon plant grown in heavy metals contaminated soil and the soil/plant interaction are reported. Cardoon is a perennial species of the Asteraceae family, native to Mediterranean countries, with different potential utilizations. Traditionally cardoon is used as a food crop but also is a very promising biomass crop for biorefinery use. For this study a new line of domestic cardoon was used, Cynara cardunculus L. var. altilis, selected for biomass production. To study the biological response of cardoon to arsenic (As) and cadmium (Cd) soil contamination, in controlled-environment conditions, the plants were grown in soil contaminated with single and combined heavy metals. Different As and Cd concentrations were tested: 1) As (92.35, 184.71 mg kg-1), 2) Cd (140.15, 280.31 mg kg-1), 3) As+Cd (92.35+140.15, 184.71+280.31 mg kg-1). The biomass production was determined through biometric measurements of the aboveground part (leaves and shoots) and root system at different stage of biological cycle. The results show that, under Cd or Cd+As treatment, the plants have grown with a behavior similar to the untreated plants. The presence of As alone in the soil caused a severe reduction in the plant growth, showing significant differences compared to the control. Overall, Cynara cardunculus showed a good biological tolerance to Cd in the soil. Also, the presence of Cd increased the resistance of the plants to As stresses.