Cd-induced oxidative burst in tobacco BY2 cells: Time course, subcellular location and antioxidant response

The relation between Cd and oxidative stress in BY2 cell cultures of tobacc o was studied. In response to 5mM Cd, a rapid generation of H2O2 has been d etected in tobacco cell cultures by the oxidative quenching of the fluoresc ent reporter dye pyranine. This oxidative burst reached the maximum product ion of H2O2 after 10 min of treatment with Cd. This response could be consi dered as short term hypersensitive response previous to the oxidative stres s caused by the metal at the cell plasma membrane. The observed antioxidant enzymatic response to the oxidative burst was preceded by an increased per oxidation of lipids with a significant increase in the activities of supero xide dismutase and ascorbate peroxidase. The results presented in this stud y point out to the plasma membrane as the primary target for the short term production of activated oxygen species in response to Cd in BY2 tobacco ce lls followed by a coordinated activation of the antioxidant enzymatic syste m.