In vitro seed germination and acclimatization of Encyclia cordigera (Kunth) Dressler

Abstract

• 100% germination of E. cordigera was achieved in MS ½-strenght + 0,15 g L-1 Ac. • Efficient protocols for in vitro propagation and acclimatization of E. cordigera were established. Encyclia cordigera is a Mexican native orchid, of major ornamental importance due to its beautiful and fragrant flowers. The said characteristics also create a risk for the extinction of the species, thus, the urgent necessity to stablish propagation strategies to prevent its loss. The objective of this study was to establish a protocol for asymbiotic seed germination and acclimatization of E. cordigera . For asymbiotic germination, different concentrations (¼ and ½ and full-strength) of MS medium were evaluated, adding 0.15% of activated charcoal (AC). MS medium without AC was used as a control treatment. The germination percentage was evaluated after 16 weeks of culture. The treatments used for the germination stage were also used for the development of seedlings which lasted 20 weeks, then plant length, number of roots, root length, number of shoots, and number of leaves per shoot were measured. Finally, the plants obtained were acclimatized. The ½-strength MS + 0.15% AC resulted in 100% seed germination, while ¼-strength MS + 0.15% AC yielded longer seedlings (1.53 cm long). As for the number and length of roots, MS + 0.15% AC proved to be the best medium, with 2 roots and 2 cm respectively. No significant differences between culture media were found for the number of shoots and number of leaves per shoot. The plants obtained were transferred to an acclimatization process for eight weeks in the greenhouse, 209 plants (97% survival rate) were obtained during the acclimatization process. The presented protocols will contribute to the propagation and conservation of E. cordigera , an orchid species with ornamental and economic importance.