Abstract

In vitro plant tissue culture is an important strategy for plant regeneration, micropropagation, and germplasm conservation. However, its implementation requires efficient and cost-effective protocols. The extremophile species Colobanthus quitensis has been proposed as a model plant for stress biology studies. Its distribution in Antarctica faces increasing threats from tourism and scientific activities, making ex situ conservation urgent. However, low in vitro germination rates hinder this approach, highlighting the need for protocol optimization. This study addressed two key questions: (1) What culture medium composition best stimulates C. quitensis germination? and (2) Which preconditioning and dormancy-breaking treatments are most effective for Antarctic populations? We tested variations in culture medium composition (Murashige and Skoog [MS] basal salts and sucrose), priming treatments, pH (5.5 and 5.7), and scarification methods. The results demonstrated that omitting MS in a pH 5.7 medium achieved 46.67% germination, increasing to 73.33% with 5% KCl halo-priming. However, complete MS exclusion impaired seedling development. A 25% MS medium at pH 5.5, combined with halo-priming, optimized both germination (81.67%) and seedling growth. For highly dormant Antarctic populations, mechanical scarification was essential to achieve significant germination. In conclusion, minor adjustments to medium composition and concentration provided a low-cost, efficient protocol suitable for C. quitensis and other commercially relevant species with similar dormancy challenges. © The Author(s), under exclusive licence to Springer Nature B.V. 2025.