EFFECT OF PLANT GROWTH REGULATORS ON MICROPROPAGATION OF HOSTA MINOR (BAKER) NAKAI THROUGH SHOOT TIP CULTURE

摘要

An efficient in vitro micropropagation method for Hosta minor (Baker) Nakai was established. Shoot tips (3-5 mm) explants were prepared from disinfected axillary buds and cultured on Murashige and Skoog (MS) medium supplemented with 3% (w/v) sucrose, 0.8% (w/v) agar, 1-12 mu M of 6-(gamma,gamma-dimethylallylamino)purine (2iP), N-6-benzyladenine (BA), 6-Furfurilaminopurine (kinetin, Kin), or 1-Phenyl-3-(1,2,3,-thiadiazol-5-yl) urea (thidiazuron, TDZ) and 2 or 4 mu M of TDZ combined with 0.5, 1, or 2 mu M of indole-3-acetic acid (IAA) and alpha-naphthaleneacetic acid (NAA) to induce shoot multiplication. Of the four different cytokinins studied, TDZ was most effective in producing multiple shoots. The highest rate of shoot induction (97.7%) with a mean of 24.4 shoots was attained on MS medium supplemented with 2.0 nM TDZ and 0.5 nM NAA. The in vitro-developed axillary shoots (> 1.75 cm) were transferred to half-strength MS medium with 0-8 mu M of indole-3-butyric acid (IBA) for rooting. The highest rooting frequency (100%) and a greater number of roots (11.2) with a mean length of 9.4 cm were attained on half-strength MS medium with 2 mu M IBA. The in vitro-raised H. minor plantlets were acclimatized in the greenhouse at 96% survival.