In vitro micropropagation of three orchid accessions (Orchidaceae) in the BIORENA Germplasm Bank

Abstract

Native orchids are increasingly fragile in terms of survival within ecosystems that are being progressively altered by deforestation, land-use changes, illegal trade, and many others factors. It is estimated that the number of orchids in Bolivia ranges between 2,000 and 3,000, considering both identified and unidentified species. Their unique flowering makes it essential to study them for conservation purposes. Within this framework, this research was conducted at the BIORENA Biotechnology Laboratory to propagation three accessions collected with capsule of native orchids (Orchidaceae) by establishing protocols for in vitro seed micropropagation during the establishment and multiplication phases lacking the rooting and actual conservation phases. Seed capsules were collected in October 2023 in the forest at community of San Juan de Saguayo, near Amboró Park in Bolivia. For the establishment phase, the seeds were disinfected with sodium hypochlorite (NaOCl) at 5%, 7% and 10%. A two-factor design with a completely randomized arrangement was used. Three orchid accessions (BAO-001, BAO-002, BAO-003) and three hypochlorite concentrations (5%, 7% and 10%) were used in establishment phase. During the multiplication stage, three MS medium formulations were evaluated: (1) MS supplemented with activated charcoal (AC) and indole-3-acetic acid (IAA), (2) MS supplemented with pyridoxine (P), and (3) MS supplemented with gibberellic acid (GA3). The treatment with 100% germination was achieved with 10% sodium hypochlorite. The survival rate of the accessions was 77.79%, and in the multiplication stage, the survival rate reached 100% at 45 days. In conclusion the MS + GA3 medium in accession BAO- 003 showed to be of larger size, with a greater number of leaves and a greater number of roots.