The challenges of growing orchids from seeds for conservation: An assessment of asymbiotic techniques

Abstract

Lewis Knudson first successfully germinated orchid seeds asymbiotically on artificial medium in 1922. While many orchid species have since been grown asymbiotically, the tremendous variation in how species respond to artificial medium and growth conditions ex situ has also become apparent in the past century. In this study, we reviewed published journal articles on asymbiotic orchid seed germination to provide a summary of techniques used and to evaluate if these differ between terrestrial and epiphytic species, to identify areas where additional research is needed, and to evaluate whether asymbiotic germination could be used more often in ex situ conservation. We found articles reporting successful asymbiotic germination of 270 species and 20 cultivars across Orchidaceae. Researchers often used different techniques with epiphytic versus terrestrial species, but species‐specific responses to growth media and conditions were common, indicating that individualized protocols will be necessary for most species. The widespread success in generating seedlings on artificial media suggests that asymbiotic techniques should be another tool for the conservation of rare orchid species. Further advances are needed in understanding how to introduce mycorrhizae to axenically grown orchids and to maximize the viability of seedlings reintroduced into natural habitats to fully utilize these methods for conservation.

Harnessing the power of botanical gardens: Evaluating the costs and resources needed for exceptional plant conservation

“…The three projects focused on orchids (excluding the project used to leverage further funds) ranked lower in cost, ranging from $1579 to less than $3600 per point (the latter project on orchids also included a non‐orchid and the costs were not separated). These projects involved testing the effects of media on in vitro germination (Zale et al, 2022 ), as well as some testing of the seeds for tolerance to cryopreservation and banking, and these types of projects benefited from both the large volume of literature available on orchid seed germination in vitro and the large number of seeds available for experimental treatments (Kauth et al, 2008 ; Jolman et al, 2022 ). In addition, one garden working with orchid seeds noted that, although much of the cryopreservation work was dependent on full‐time skilled labor, some components, such as curation, viability testing, and data collection, could be done by trained volunteers and students, which helped to offset costs and scale up the work.…”

Categorización del riesgo de extinción y primer registro para Colombia de Cycnoches suarezii (Orchidaceae, Catasetinae)

“…Sin embargo, esta estrategia puede desencadenar la explotación descontrolada que, ante la falta de control, conlleve a la disminución o la extinción de las poblaciones silvestres (Phelps et al, 2014;Cruz-Garcia et al, 2015). Una estrategia ex situ con gran proyección es la reproducción in vitro de orquídeas con fines comerciales y de conservación a partir de semillas, usando los servicios de alguno de los laboratorios existentes en el país, categorizadas como Productos Forestales No Maderables (PFNM) y susceptibles de aprovechamiento en bosques y ANP (Jolman et al, 2022). Así mismo, un gran avance para la conservación de orquídeas se ha dado mediante el uso de embriones encapsulados o semillas artificiales, para la restauración de poblaciones mediante su dispersión en ambientes degradados o con poblaciones reducidas, una estrategia que podría aplicarse a cualquier especie de orquídea (Zhao et al, 2021;Cárdenas Guarín et al, 2022).…”

Building capacity in the conservation of exceptional plant species

“…Many orchids are considered exceptional species due to the relatively short longevity of their seeds when frozen at −20°C (Merritt et al, 2014 ), and in vitro methods are routinely used for viability testing and germination of orchid seeds. Jolman et al ( 2022 ) offer a comprehensive overview of the issues surrounding asymbiotic germination of orchid seeds, a process that allows practitioners to sidestep the difficulties of germinating species with their symbiotic mycorrhizal fungi. This work can give researchers a jumping‐off point for the development of in vitro germination protocols for new species in ex situ collections.…”