Antioxidative responses in radish [Raphanus sativus L.] plants stressed by copper and lead in nutrient solution and soil

Radish (Raphanus sativus L.) is commonly grown in urban and suburban areas where the soil may be polluted with heavy metals such as Cu or Pb. In this study, short exposure of radish plantlets to 0.5 mM Cu or Pb in nutrient solution (two days) in growth chamber conditions elicited an antioxidative response, measured in terms of lipid peroxidation, protein and proline accumulation, and peroxidase and catalase activity. Longer exposure to Cu or Pb when radish was grown outdoors for 50 days in pots filled with field soil with different Cu and Pb content also resulted in higher lipid peroxidation and proline accumulation, and altered protein content and enzyme activity. The tested parameters of radish antioxidative responses to heavy metal stress differed depending on plant part (leaf or hypocotyl) and stress intensity (heavy metal content in growth medium, exposure duration). The reported data show that plants grown in soil from sites where this crop could be cultivated do show an oxidative stress response similar but not identical to that seen under laboratory treatment with heavy metals.