In vitro propagation of Tillandsia eizii
Pickens, Kimberly Ann
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Tillandsia eizii is an epiphytic bromeliad that due to over-collection, habitat destruction, and physiological constraints has declined to near threatened status. This species exhibits high mortality in the wild and seed are characterized by low germination and ephemeral viability. In vitro propagation techniques to enhance seed germination and seedling growth may be a means to conserve this species. Clonal propagation via tissue culture may also be a means to repopulate native stands while meeting the demands for this species as an ornamental or ceremonial plant. The effects of sterilization regime, photoperiod, temperature, sucrose concentration, and auxin content on seed germination and growth of Tillandsia eizii were assessed. Also evaluated were the effects of potting substrate on the survival and growth of in vitro-grown seedlings after outplanting. A protocol for the effective in vitro propagation of Tillandsia eizii seed was determined. A sterilization protocol was identified consisting of 70% ethanol for 2 minutes followed by 2.6% NaOCl for 40 minutes. The presence of sucrose was found to have no effect on germination and seedling growth. The presence of NAA during germination inhibited growth, while a 16-hour photoperiod at 22 o C promoted better development than darkness or higher temperatures. In vitro-grown plants were successfully acclimatized and outplanted. Over 86% survival and rapid growth were obtained with pine bark or a mixture of pine: orchid bark: potting mix: perlite (2:2:2:1). In other studies, adventitious bud proliferation was induced from axenically germinated seedling material. Parameters evaluated were the age of explant material at the time of transfer onto bud-induction medium, the concentration of plant growth regulators, and the period of exposure to induction medium. Light and scanning electron microscopy were used to establish the origin and development of buds. In clonal propagation studies, best results were achieved with a concentration of 2 mg/l (8.88 µM) BA and 0.05 (2.69 µM) - 0.1 mg/l (5.37 µM) NAA. Experiments revealed that a 30-day induction period was preferable using explants that were 12-weeks old.