Effective Micropropagation of Ailanthus altissima ‘Hongyechun’, an Ornamental and Economically-Important Tree of Simaroubaceae

Abstract This research developed an effective protocol for micropropagation of Ailanthus altissima ‘Hongyechun’. Axillary shoots from dormant twigs dipped in water were sterilized with 70% ethanol for 15 s and with 0.1% HgCl2 solution for 7 min, resulting in the survival rate of 71.3% and the contamination rate of 0%. The explants were then inoculated on Murashige and Skoog medium (MS medium) supplemented with 1 mg L−1 6-benzyladenine (6-BA), 0.1 mg L−1 indole-3-acetic acid and 500 mg L−1 polyvinylpyrrolidone (PVP), yielding the browning rate of 8.5% and the in vitro shoot induction of 79.8%. In vitro shoots were successfully multiplicated on modified MS medium (KNO3 1050 mg L−1, NH4NO3 925 mg L−1, MgSO4·7H2O 285 mg L−1, CaCl2·2H2O 300 mg L−1) supplemented with 1.0 mg L−1 6-BA, 0.1 mg L−1 indole-3-butyric acid (IBA) and 1000 mg L−1 PVP, resulting in the shoot proliferation rate of 4.2 fold and the shoot vitrification rate of 4.5%. The most suitable medium for in vitro rooting was 1/2 MS medium supplemented with 1.5 mg L−1 IBA, 1000 mg L−1 PVP, 2% sucrose and 0.6% agar, resulting in the root induction rate of 85.8%. The suitable acclimatization medium was a mixture of vermiculite, peat, carbonized rice husk, fermented sawdust and coal ash (at a volume ratio of 2 : 2 : 4 : 1 : 1). About 85% of the in vitro plantlets were acclimatized in glasshouse after 35 days. The rooted and acclimatized plants were successfully transferred to soil after light-hardening under sunlight for 5–7 days resulting in 93% survival.