Antioxidant Capacity as a Marker for Assessing theIn VitroPerformance of the EndangeredCistus heterophyllus

Cistus heterophyllussubsp.carthaginensisis an endemic and endangered species from the SE Mediterranean coastal region of Spain. Within the framework of the efforts aiming to species conservation,in vitroculture techniques could be of interest. The aim of this study was to evaluate the antioxidant capacity ofC. heterophyllusshoot cultures as a possible marker ofin vitroperformance. The effects of five different basal salt formulations and cytokinin levels onin vitroperformance and antioxidant capacity were examined. K+/Na+and Ca2+/Na+ratios initially present in culture media greatly affected the antioxidant capacity (the lower the ratios the higher the antioxidant capacity). Increasing concentrations of BA resulted in higher antioxidant capacity. The results obtained point to antioxidant capacity as being a marker of incidence of stress conditions inin vitroculturedC. heterophyllus. A good correlation was found between antioxidant capacity and total soluble phenolics present inCistusextracts. Catechin was identified in all the extracts and its levels were found to change parallel to the antioxidant capacity, pointing to a prominent role played by this flavonoid inC. heterophyllusdefence against oxidative stress, which in turn affects thein vitroperformance of this species.