Effects of plant preservative mixture™ on in vitro germination of Dendrobium thyrsiflorum Rchb.f. and its application in orchid conservation

Effects of plant preservative mixture™ on in vitro germination of Dendrobium thyrsiflorum Rchb.f. and its application in orchid conservation

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 MixtureTM (PPMTM) should be emphasized. In this study, we used Dendrobium thyrsiflorum Rchb.f. (1875) seeds and seedlings as a model for the evaluation of PPMTM’s phyto- toxicity in the meristematic tissues of epiphytic orchids. PPMTM had no observable inhibitory effect on protocorm, shoot, or root development when it was supplemented at 0.1%. PPMTM 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% PPMTM to culture media was successfully implemented to establish in vitro cultures of other rare orchid species in our conservation program.