Evaluation of the effect of three growth regulators in the germination of Comparettia falcata seeds under in vitro conditions

The effect of 3-indoleacetic acid (IAA), 6-furfurylaminopurine (kinetin), and gibberellic acid (GA(3)) on germination of the orchid Comparettia falcata was evaluated in a factorial experiment (4x4x4) with Murashige and Skoog (1962) basal medium. It was established that seeds of this orchid could be maintained under aseptic conditions as long as the necessary nutrients and appropriate concentrations of growth regulators were provided. Of the three growth regulators used, IAA significantly decreased seed germination of Comparettia falcata. There was a synergistic effect in the kinetin:GA(3) combination that produced a positive response in both percentage seed germination and development of seedlings. This study describes a single medium-based protocol able to achieve more than 160 000 seedlings within 21 wk, starting from a single capsule, sufficient for both large-scale propagation and in vitro conservation of this threatened orchid.