Salt-induced changes in the antioxidant system and viability of oilseed rape

This work was aimed to investigate the effect of salt (NaCl) stress on three oilseed rape (Brassica napus L.) cultivars: 'Banacanka', 'Jasna' and 'Kata'. The following parameters were determined: antioxidant enzymes superoxide dismutase (SOD) and guaiacol peroxidase (GPX), reduced glutathione (GSH) quantity, lipid peroxidation (LP) intensity, radical-scavenging capacity (DPPH-RSC), hydroxyl radical scavenging ((OH)-O-center dot radicals) and ferric reducing antioxidant power (FRAP). Seed viability was determined using the standard laboratory test for germination as well as the seed accelerated aging test measuring the germination, shoot and root length. The plants were subjected to three salt treatments: 0, 100, 150 and 200 mmol dm(-3) NaCl for 7 days. All three cultivars responded with an increase of lipid peroxidation in seedlings and with a decrease of GPX activity. 'Banacanka' was found to be the most vulnerable cultivar, with an increase of 237% of LP intensity in comparison to the control at the highest NaCl concentration. The induction of the SOD activity was observed for all three cultivars by different NaCl concentrations. The antioxidant capacity measured by FRAP, DPPH-RSC and (OH)-O-center dot radicals was also induced, especially FRAP at the highest concentration in the cultivar 'Jasna' (by 282%). Germination, shoot and root length decreased for all investigated cultivars. Our results showed that cultivar 'Jasna' is the most adapted to salt stress because of the highest SOD activity and accumulation of antioxidants. Furthermore, this research suggests that some of the antioxidant parameters can be useful biochemical markers for the selection of oilseed rape tolerant cultivars under the conditions of salinity.