In vitro conservation is one of the most effective strategies for rare plant protection, especially for orchid species. To maximize the success rates of in vitro explant establishment (stage I) in conservation programs, the application of tissue cultu...
In vitro conservation is one of the most effective strategies for rare plant protection, especially for orchid species. To maximize the success rates of in vitro explant establishment (stage I) in conservation programs, the application of tissue culture additives such as Plant Preservative Mixture<sup>TM</sup> (PPM<sup>TM</sup>) should be emphasized. In this study, we used Dendrobium thyrsiflorum Rchb.f. (1875) seeds and seedlings as a model for the evaluation of PPM<sup>TM</sup>'s phytotoxicity in the meristematic tissues of epiphytic orchids. PPM<sup>TM</sup> had no observable inhibitory effect on protocorm, shoot, or root development when it was supplemented at 0.1%. PPM<sup>TM</sup> supplementation caused adverse effects on D. thyrsiflorum explants at concentrations > 0.2%. At high concentrations, young in vitro seedlings showed damage, especially at the root tissue level. Based on this model, supplementation of 0.1-0.2% PPM<sup>TM</sup> to culture media was successfully implemented to establish in vitro cultures of other rare orchid species in our conservation program.