Asymbiotic germination of Bipinnula fimbriata (Orchidaceae) seeds in different culture media

Bipinnula fimbriata is a terrestrial orchid endemic to Chile with high ornamental potential. Previous studies reported symbiotic germination of B. fimbriata, but no successful asymbiotic germination has been reported for any Chilean orchid. We observed asymbiotic germination of B. fimbriata seeds in five different culture media. Naturally produced seeds were put in Petri dishes with five different culture media: agar water (AW), culture medium banana (CMB), culture medium tomato (CMT), Knudson C (KC) and Malmgren modified terrestrial orchid medium (MM). Seed viability, asymbiotic germination and embryo development were evaluated in all media. Plates were put in the dark at 24 ± 1°C for four weeks and then transferred to a 16-/8-hour light/dark cycle at 20 ± 1°C for another four weeks. In the first four weeks, seed germination surpassed 30% in all culture media. After eight weeks, seeds in MM medium developed a shoot meristem. However, seeds in CMB, CMT and KC evidenced rhizoids, and seeds in AW only germinated. We found significant differences in germination percentage between media. MM medium resulted in the highest germination percentage and AW in the lowest. Asymbiotic germination of Chilean orchids could be a viable method for future conservation, restoration and propagation initiatives.