Adventitious shoot regeneration from in vitro leaves of Eupatorium chinense L.

Eupatorium chinense L. is highly valued for its medicinal properties. However, this species has a low propagation rate, so that the demand for the resource cannot be met adequately. The present study investigated the effects of various hormone combinations on callus formation, shoot induction, proliferation, and root growth in E. chinense L. to develop a rapid tissue-culture propagation method. Callus induction was achieved from leaf explants of aseptic in vitro plantlets on Murashige and Skoog (MS) medium fortified with 2.0 mg/L 6-benzyladenine (BA), 0.2 mg/L 2,4-dichlorophenoxyacetic acid (2,4-D), and 0.2 mg/L alpha-naphthaleneacetic acid (NAA), with a response rate of 75.66% among explants. The optimal callus regeneration medium contained 2 mg/L BA, 0.6 mg/L NAA, 0.5 mg/L 2,4-D, 1.0 mg/L Kinetin (KT), and 30 g/L sucrose, with a bud emergence rate of 27.45%. Leaf segments exhibited a direct shoot induction rate of up to 72.00% when cultured on MS + BA 6.0 mg/L + NAA 0.5 mg/L + 30 g/L sucrose. The optimal proliferation culture medium for adventitious buds was MS + BA 2 mg/L + 30 g/L sucrose, with a proliferation coefficient of 10.69. Furthermore, 1/2MS + IBA 0.5 mg/L + NAA 0.1 mg/L + 30 g/L sucrose is optimal for rooting, yielding a mean of 7.04 roots, a primary root length of 5-6 cm, a rooting rate of 92.86%, and a transplant survival rate exceeding 95%. This is the first report of an efficient propagation system for E. chinense L. tissue culture and demonstrated its potential for large-scale seedling production and biotechnological practices for its genetic improvement.