Shoot regeneration from petioles of coral bells (Heuchera sanguinea Engelm.) cultured in vitro, and subsequent planting and flowering ex vitro

Summary Successful shoot regeneration from petioles, leaves, and petioles with leaves cultured in vitro is reported in Heuchera sanguinea. Petioles or petioles with leaves regenerated more shoots than leaves alone. For culture, the optimum hormonal concentrations were 0.19 μM α-naphthaleneacetic acid combined with 0.44 or 4.4 μM benzyladenine in Murashige and Skoog-based (MS) medium: the regenerating rate and the number of shoots per explant were 60% and 8.6–9.7, respectively. Histological study on petiole culture showed dividing cell clusters including vascular tissues after 1 wk, callus including several dividing cell clusters at the periphery after 3 wk and then apical meristems with immature leaves after 5 wk. Rooting from the regenerated shoots was highest (95%) on MS medium containing 4.9 μM indole-3-butyric acid. Seventy-three percent of rooted plants were successfully acclimatized in pots. When they were cultured in the field, the plants grew and most flowered the following year over winter.