Antioxidant Responses of Strawberry Plants under Stress Conditions

The purpose of this study was to examine antioxidant responses of strawberry under salinity or drought conditions. Strawberry plants (Fragaria x ananassa 'Camarosa') were supplied with a solution containing 0, 10, 20, or 40 mM NaCl. Changes in ascorbic acid, total phenolics, carotenoids, antioxidant capacity, phenylammonialyase (PAL) and peroxidase (POD) activities were determined. Salinity enhanced the secondary metabolism, enabling roots and leaves to respond to salinity for defense requirements (an increase in antioxidant capacity) but not accordingly to the salinity level. To examine the effect of drought, plants were cultivated in a solution supplemented with 0 or 150 g L-1 polyethylene glycol (PEG 4000) for 24 h. Results suggested that strawberry plants possess specific mechanisms to detoxify reactive oxygen species which include activation and cooperation of catalase (CAT), peroxidase (POD) and superoxide dismutase (SOD). Furthermore, proline may be an indicator of drought-stress or stress-tolerance and hydrogen peroxide (H2O2) may be correlated with the stress response.