Asymbiotic germination of Chloraea disoides Lindl. (Orchidaceae), a critically endangered orchid endemic to Chile

Abstract

Degradation of ecosystems is one of the main causes of the global decline in biodiversity. Many species are threatened with extinction and urgent actions are needed. Chloraea disoides is a critically endangered terrestrial orchid endemic to Chile. Our main goal was to evaluate the effect of three culture media in the asymbiotic germination of this species, aiming at its propagation in the long term. We tested the effect of Malmgren modified terrestrial orchid medium (MM), modified Murashige & Skoog medium (MS1/2), and agar-water (AW). After one week of incubation, seeds in all three media reached pre-germination stage. After four weeks, germination was achieved in MM and MS1/2. Protocorm stage was reached after 6 weeks only in MM. After 13-14 weeks, embryos reached the rhizoid stage in MM and MS1/2 and did not further develop until the end of the experiment (week 16). Overall, asymbiotic germination was statistically higher in MM and MS1/2 compared to AW, but very low nevertheless, compared to other Chilean Chloraea species, being lower than 8%. The laboratory propagation of C. disoides could be a key strategy to avoid its extinction in the short term but further studies are needed to fully understand its low germination capacity.