Establishment of in vitro plant regeneration system for Chimonanthus praecox (L.)
An efficient protocol for plant regeneration of Chimonanthus praecox (L.) Link, was developed using leaves from seedlings of seeds. Shoots induction were influenced by cytokinins and nodal positions. The results show that the highest callus induction frequency was obtained on MS medium supplemented with 2.0 mg l−1 6-benzyladenine (6-BA) and 0.9 mg l−1 1-naphthalene-acetic acid (NAA) after 10 days incubation in darkness. The frequency of callus induction of different nodal leaves (from the first to the forth node) varied from 70.0 to 93.5%; the highest frequency of callus induction (93.5%) was observed in the second node group. Through many times subculture of callus, green and compact callus was selected and transferred to regeneration medium (MS, 1/2 MS and woody plant medium (WPM) supplemented with different concentrations of thidiazuron (TDZ) (2.37, 4.74 and 9.48 mg l−1) and NAA (0.74, 1.48, and 2.96 mg l−1). It was shown that the optimal combination of the three factors was WPM + NAA + TDZ. The highest adventitious shoot regeneration frequency of leaf explants (71.33%) and the highest mean number of shoots per explant (2.23) were obtained on WPM supplemented with 2.37 mg l−1 TDZ and 1.48 mg l−1 NAA. Optimal rooting was seen on 1/2 MS medium with 1.5 mg l−1 IBA for eight days, followed by transfer to hormone-free MS medium. Rooted plantlets were easily acclimated in a glasshouse.
Key words: Chimonanthus praecox, in vitro regeneration, adventitious buds.