Response to stress induced by different potentially toxic elements (As, Cd, Cu and Na) in rapeseed leaves

The main objective of this work was to study the effect of different potentially toxic elements (PTE) in the same experimental conditions in leaves of Brassica napus L. plants. The stress was induced by an essential heavy metal (Cu), a non-essential heavy metal (Cd), a metalloid (As) and salinity (NaCl). Plants were able to grow in all the stressful conditions, but with lower biomass in the NaCl study and with chlorophyll levels being more affected in Cu and Cd stresses. Globally, the enzymatic antioxidative defense was not strongly activated except for the salinity study, where the activities of SOD, CAT and APX were induced. This shows that other defense mechanisms are active in the Cd and Cu stress and the increase in S uptake in these experiments suggest the involvement of glutathione and phytochelatins. The homeostasis of essential elements was differentially affected, although a reduction of Fe content was detected in all cases.