A plant regeneration protocol from callus cultures of medicinal plant Rhodomyrtus tomentosa

Rhodomyrtus tomentosa (Ait.) Hask is a multifunctional shrub of the Myrtaceae, which uniquely combines ornamental, medicinal, and health purposes. In this study, for the first time, a regeneration system was established in R. tomentosa. Callus was induced on Murashige and Skoog (MS) medium with 0.5 mg L-1 6-benzyladenine (BA), 0.05 mg L-1 alpha-naphthaleneacetic acid (NAA), and 0.005 mg L-1 thidiazuron (TDZ), from tender leaves and stems. Light yellow-green, rigidity, granule callus was induced, 93.33% of which could differentiate into adventitious shoots within 60 d. The optimal shoot proliferation medium was 1/2 MS medium with 6-BA 1 mg L-1 and NAA 0.1 mg L-1, and cultured in high temperature high light intensity (26 degrees C, 120 mu mol m(-2)s(-1)) got the highest rate (86.67%) for regeneration response within 60 days. Adventitious roots exhibited the highest rate at 100% on PGR-free 1/2 MS medium. Within 2 months, over 90% of plantlets survived when transferred to a substrate of sand/soil (1:2 ratio). Key messageThis study provides an efficient protocol to regenerate the multifunctional shrub rose myrtle (Rhodomyrtus tomentosa) from embryogenic calli induced from tender leaves and stems.