Study of the antioxidant enzymatic system during shoot development from cultured intercalar meristems of saffron

As preliminary research to develop a clonal in vitro propagation system for saffron, we have evaluated the morphogenic response of intercalary meristems present in shoots from sprouting saffron corms when cultured in media with different cytokinins. The best results in terms of shoot production and quality were achieved in the medium supplemented with 5 mg/l of benzylaminopurine (BAP). During the multiplication of the meristems, several changes in the activities of the antioxidant enzymatic system were detected. Catalase (CAT) activity was reduced in the presence of the assayed cytokinins, whereas peroxidase (POX) activity was stimulated with all the cytokinins assayed. When TDZ (thidizuron) was used, a slight decrease in superoxide dismutase (SOD) activity occurred, whereas BAP and 2iP (2-isopentenyl adenine) treatments produced a significant increase in SOD activity. The ascorbate–glutathione cycle enzymes showed a similar pattern in response to the addition of cytokinins. These results suggest a possible use of antioxidant enzyme activities as a parameter that could be use to evaluate the efficiency of micropropagation protocols for saffron and even in other species.