Through a dedicated year of research, successful outcomes were achieved with Arundina species, showcasing germination manifested by noticeable color shifts and protocorm development within a mere week. However, my current focus on Dendrobium Nobile presents a perplexing challenge. Despite meticulously replicating the treatment and maintaining consistent environmental conditions, repeated experiments have yielded no results even after a span of 10 days. It's worth noting that all variables remain constant, including the freshness of the seeds. The only noteworthy divergence is the time of sowing; whereas the earlier success occurred in September, the current attempts are unfolding in the months of July and August. Could this shift in sowing timing potentially account for the observed non-germination tendencies?
Try again, but with only viable seeds. You can test for viability using the flotation test. Seeds that sink in water are viable. And try longer too :)
Orchid dormancy is an overwhelmingly poorly understood concept. Some research suggests that the initiation of germination might be closely related to changes in environmental factors or fungal activity, at least in temperate species.
Considering the ecology of Dendrobium nobile, having a pronounced dormancy period, it would make sense for the seeds to rely on external factors to promote germination at a favourable time of year when conditions will promote seedling development.
Fully mature seeds also tend to exhibit lower germination rates, approaching zero, probably as the last stages of seed development account for the induction of seed dormancy.
Andrew Paul McKenzie Pegman suggested viability is an essential factor. Sometimes, orchid seeds are coated with a hydrophobic coat. To test the viability you can maybe look into the methods provided in the following paper:
Vladimir Vujanovic, Marc St-Arnaud, Denis Barabé, Geneviève Thibeault, Viability Testing of Orchid Seed and the Promotion of Colouration and Germination, Annals of Botany, Volume 86, Issue 1, July 2000, Pages 79–86, https://doi.org/10.1006/anbo.2000.1162
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