In vitro germination and propagation of Apocynum lancifolium Russanov, an endemic species in South Korea

Apocynum lancifolium Russanov is an endangered and ecologically important plant endemic to South Korea. However, neither the mass germination of Apocynum seeds nor the production of its plantlets using in vitro culture systems have been reported. Therefore, we conducted in vitro experiments to investigate the effects of temperature on seed germination inoculated onto half-strength MS medium. Additionally, we described the mass proliferation of A. lancifolium by using an in vitro stem cutting propagation system. The effect of temperature on A. lancifolium seed germination was significant (p = 0.018). A. lancifolium germinated 2 d after inoculation, with germination rates of 64%, 54%, 50%, and 35% at 25, 20, 15/25, and 15 °C, respectively. A. lancifolium seeds inoculated at 25 °C had the highest germination rate (64 ± 4.85%) and daily mean for in vitro propagation and regeneration. A half-strength WPM was more efficient than any other salt composition (MS and DKW) for the growth of A. lancifolium, although the effects of three different basal culture media on the growth of A. lancifolium were not significant. This in vitro germination, propagation, and regeneration system for A. lancifolium provides a means to substantially advance A. lancifolium germplasm conservation and restoration.