Zeatin and TDZ-induced Shoot Proliferation and Use of Bioreactor in Clonal Propagation of Medicinal Herb, Roseroot (Rhodiola rosea L)

A procedure for in vitro propagation of roseroots (Rhodiola rosea L), a medicinal plant, was developed using a RITA bioreactor system containing liquid medium, combined with a gelled medium. Wild roseroot clones: ‘RCi’, ‘RC2’ and ‘RC3’ were established on a basal medium (BM) from in vitro-germinated seedlings on half-strength Murashige and Skoog (MS) salts. TDZ at 2–4 μM supported shoot proliferation but inhibited shoot elongation of ‘RCi’ shoots on gelled medium. Clones differed significantly with respect to multiplication rate with ‘RCi’ producing the most shoots per explant on gelled BM with 2 μM zeatin. In a bioreactor system, TDZ supported rapid shoot proliferation at lower concentration (0.5 μM) but induced hyperhydricity at more than 0.5 μM. Bioreactor-multiplied hyperhydric shoots of all clones when transferred to gelled medium containing 1–2 μM zeatin produced normal shoots within 4 wk of culture. Shoots were rooted in vitro on BM void of growth regulators. Almost all (9U to 95%) in vitro plantlets survived when transferred to potting medium.