In Vitro Propagation of Paphiopedilum spicerianum (Reichb. F.) Pfitz.

摘要

The goal of this study was to investigate various factors affecting germination in vitro and to establish a protocol for propagation of Paphiopedilum spicerianum which would provide information on various events of seed germination and seedling development thus helping to propagate and conserve this species. Capsules were harvested at two different stages of development. Six asymbiotic orchid seed germination media (Knudson C (KC), modified Knudson C (MKC), Terrestrial orchid medium (BM), modified Terrestrial orchid medium (BM1), Vacin and Went (VW) and Nitsch and Nitcsh (N)) were examined for their effectiveness in promoting seed germination, protocorm and seedling development of P. spicerianum. Besides checking the efficacy of different media, theeffect of capsule maturity level, photoperiod (0/24 h; 12/12 h L/D), activated charcoal, plant growth regulators [6-benzyladenine (BA) and a-naphthalene acetic acid (NAA)] on seed germination was also assessed. The seeds from undehisced green capsules germinated with better frequency than seeds from mature burst capsules. Germination occurred regardless of media type. Amongst all media tested, highest germination percentage (62.75 ± 2.63%) was achieved in BM1 and activated charcoal (AC) under continuous darkness. The addition of NAA (1.5 mg l~(-1)) to medium resulted in the early formation of seedlings within 21.05 ± 0.05 weeks. Higher concentration of BA reduced the percentage of seed germination. After germination for 8 weeks in total darkness atthe protocorm stage, a shift from darkness to light conditions (12/12 h L/D) was required for differentiation of protocorms into seedlings. Chlorophyll development was a post-protocorm phenomenon in the cultures. The current study has the potential to assist with the future development of ex situ conservation of this endangered species by producing innumerable viable seedlings.