Micropropagation of Ilex Glabra (L.) A. Gray

Inkberry (Ilex glabra (L.) A. Gray) is a popular native evergreen shrub with glossy green foliage for ornamentals. To mass produce inkberry for the nursery market, nodal segments containing one axillary bud (1-1.5 cm) were disinfested using 10% bleach and established on MS medium without hormone at 27° C and 16 h photoperiod. The sprouted shoots (~1.0 cm) were cultured on MS medium supplemented with 6-Benzyl Aminopurine (BAP),  Kinetin (KT) or Zeatin (ZT) at 0.5, 1.0, 2.0, or 4.0 mg·L^-1. After 38 days, BAP and ZT significantly induced multiple shoot formation with multiplication rates of 4-6, while the multiplication rate of KT was less than 2. Shoots cultured on ZT grew significantly faster than that of BAP and KT. The height of the longest shoots treated with ZT was 4.6 cm, which was 1.6-2.2 times greater than those treated with BAP or KT.  To induce rooting, shoots (~ 2 cm) were subcultured on ¼ strength MS medium containing either IBA or NAA at 0.5, 1.0, or 2.0 mg·L^-1. Adventitious roots formed after 3-4 weeks in cultivation. IBA, at 1.0 or 2.0 mg·L^-1, produced the best rooting compared to other treatments. After 38 days, 66.7% and 100% of shoots were rooted at 1.0 and 2.0 mg·L^-1 IBA, respectively.  The average number of roots per shoot was about 15, which was 1.6-3.1 times as much as that of other treatments. All rooted plantlets were then transplanted into a mix of peat moss: perlite (1:1 v/v) and acclimated in a mist system. About 73.6% of the plantlets survived after grown for 35 days. This micropropagation procedure could be used for commercial mass production of newly bred inkberry cultivars.