Adventitious shoot regeneration and micropropagation of the Japanese endangered Hylotelephium sieboldii (Sweet ex Hook.) H. Ohba and H. sieboldii var. ettyuense (Tomida) H. Ohba

Abstract

Due to indiscriminate collection, the natural habitat of Hylotelephium sieboldii and H. sieboldii var. ettyuense have been significantly reduced. For ex situ conservation and efficient vegetative propagation, a micropropagation system based on adventitious shoot regeneration was developed for these two endangered species. Leaves, stems and roots of in vitro-grown plantlets, and flower buds of greenhouse-grown plants were used as explants. For H. sieboldii, adventitious shoots were most efficiently regenerated from flower bud explants on a medium containing 1 mg l⁻¹ each of NAA and BA. Adventitious shoot regeneration from flower bud explants under this condition was also obtained in H. sieboldii var. ettyuense, but with lower efficiencies. Adventitious shoots of both species rooted and developed into plantlets on a medium containing 0.1 mg l⁻¹ IBA. Almost all of these plantlets were successfully transplanted to the greenhouse. At least at early stage of growth, they showed no apparent morphological alterations.