Metabolic stability of in vitro plants derived from cryopreserved shoot tips of Passiflora suberosa - chromatographic analysis and assessment of antioxidant activity

Passiflora suberosa, commonly known as corky passionflower or corky stem passion fruit, is a wild passion fruit species with agronomic, ornamental, and medicinal potentials. In a previous study, we developed an efficient protocol for long-term conservation of P. suberosa through the cryopreservation of shoot tips, using the V-Cryo-plate technique, and identified osmoprotection and cryoprotectant exposure as the critical stages influencing post-freezing recovery. The present work aimed to evaluate the effect of antioxidants on recovery rates and the metabolic stability of plants derived from cryopreserved shoot tips. The addition of different concentrations of ascorbic acid or glutathione during the osmoprotection and cryoprotection stages did not improve the recovery rates. High-Performance Liquid Chromatography (HPLC) analysis of in vitro plants derived from cryopreserved materials indicated that the biosynthetic capacity of the recovered plants was unaffected by the cryopreservation process. Furthermore, no significant changes were observed in the antioxidant potential of the recovered plants, as assessed by their ability to scavenge DPPH radicals and chelate metal ions. These results confirm that cryopreservation is an effective long-term conservation strategy for P. suberosa and provide new insights into the cellular responses of tropical plants to the stress induced by the procedures involved in V-Cryo-plate protocols.

Key words:
cryoprotection; oxidative stress; passion fruit; secondary metabolites; V-Cryo-plate