In vitro Germination and Micropropagation of Geodorum densiflorum (Lam.) Schltr., an Endangered Orchid Species

摘要

Seeds of Geodorum densiflorum (Lam.) Schltr. were aseptically cultured on 0.8% (w/v) agar solidified Murashige and Skoog (MS) and Phytamax (PM) media. Seeds germinated and formed light green globular structures on both the media. These globular structures failed to produce seedlings on PM medium, where it proliferated and developed into irregular-shaped rhizomes with white hairy structures. On the other hand, on MS medium the globular structures directly produced tiny seedlings which underwent elongation in PGRs supplemented MS medium. A composition of 2.0 mg/1 NAA and 2.0 mg/1 BAP proved best for enhancing elongation. The elongated seedlings were grown on half and full strength MS medium with or without IAA and activated charcoal (AC). For sound development of the root system MS + 3% (w/v) suciose + 1.0 mg/1 IAA + 0.1% (w/v) AC proved best. The irregular shaped rhizomes as developed on PM medium were further used for mass production of seedlings. Rhizome tips produced multiple shoot buds on PGRs (NAA, IAA, IBA, picloram, BAP and zeatin) supplemented media. The highest number of multiple shoot buds per segment was observed on 0.8% (w/v) agar solidified MS + 3% (w/v) sucrose + 2.0 mg/1 BAP. The multiple shoot buds underwent elongation on the same media and the maximum rate of elongation was recorded on 0.8% (w/v) agar solidified MS + 3% (w/v) sucrose + 2.0 mg/1 NAA + 2.0 mg/1 BAP. The elongated seedlings were rooted in the rooting medium and the plantlets after acclimatization were established inpot.