Parameters optimization for in vitro propagation of Colobanthus quitensis (Kunth) Bartl.

Colobanthus quitensis is one of the two native vascular plants that inhabit Antarctica. In addition, it spreads from the south of Mexico to the north of the Antarctic Peninsula and from 0 to 4200 m asl, always in extreme habitats. It is considered a model species for abiotic stress studies. Due to its small size and low accessibility to its habitats, efficient propagation methods are required to maintain it in the laboratory. The aim of this work was to optimize some critical parameters in the in vitro propagation of this species related to physical and chemical aspects to avoid negative effects such as explants yellowing and death and improve the conditioning of new plantlets, as well as response to different hormonal combinations. Explants from previously established in vitro seedlings were used. When the vessels were covered with a double layer of aluminum foil, water loss in the medium and the tissues was avoided, as well as the yellowing of the buds was reduced. The addition of silver thiosulfate to the medium stimulated the regeneration of buds and roots, and at a concentration of 10 mu M inhibited the yellowing and death, of buds by 50% and 25%, respectively. At 28 days of culture in the glass vessels, 49% less yellowing was observed, 7% more new buds and 24% more roots than in the Magenta box. The light intensity between 28-45 mu mol m(-2)s(-1) decreased the negative effects and stimulated regeneration. C. quitensis responds to different hormonal combinations, but more studies are needed to establish the optimal combination for the individuals originated from different habitats.