In vitro and Ex vitro Propagations of Astilboides tabularis (Hemsl.) Engl. as a Rare and Endangered Species

Abstract

This study was conducted to establish in vitro and ex vitro propagation systems and to secure the genetic resource for ex-situ conservation of Astilboides tabularis (Hemsl.) Engl. as a rare and endangered species. Plant materials were collected and prepared for various treatments for in vitro propagation by plant tissue culture and ex vitro propagation by root cuttings. For callus induction, leaf explants cultured on MS medium with BA 0.1 mg L-1 showed the highest rate at 24%, whereas the petioles supplemented with BA 0.5 mg L-1 exhibited the highest rate at 14%. Root explants treated with BA alone did not induce callus formation whereas a combination of BA and NAA showed 100% callus induction at concentrations of BA 0.1 + NAA 0.1 mg L1 and BA 1.0 + NAA 1.0 mgL-1. Shoots were produced at 50% from leaf explants treated with BA 0.1 mg L-1 concentration, whereas no shoots were observed even with the treatments from root segments. Rooting experiments supplemented with NAA 0.01 mgL-1 had the highest rate up to 86% with 15 small roots and 1.3 cm length. In order to increase the efficiency of in vitro potential regeneration of A. tabularis, additional studies would be needed for higher rooting rates from callus and induced shoot. Ex vitro propagation by root cuttings with large diameter and 7 cm length grew well above ground, whereas medium diameter and 7 cm length showed good rooting system in the first year. During the second year, small shoots grew well for medium diameter, whereas there were no significant differences among other treatments. Thus, the size and length of the cuttings were for the plants in the first year, which did not affect growth in the second year. Based on this work, A. tabularis root cutting for mass propagation would be possible by small size cutting system.