Plant Regeneration from Leaf Explants of the Medicinal Herb Wedelia chinensis

Wedelia chinensis, belonging to the Asteraceae family, has been used in folk medicine in East and South Asia for the treatment of common inflammatory diseases and protection against liver toxicity. Previously, in vitro propagation through different tissue explants has been reported, including through nodal segments, axillary buds, and shoot tips, whereas leaf segments failed to proliferate. Here, we report on the in vitro propagation of W. chinensis by culturing young leaf explants in MS medium supplemented with 0.5 mg/L alpha-naphthaleneacetic acid (NAA), 0.75 mg/L thidiazuron (TDZ), 1 mg/L gibberellic acid (GA(3)), 3.75 mg/L adenine, 3% sucrose, and 0.8% agar at pH 5.8. Calli were observed in all explants derived from the youngest top two leaves, and the average percentage of shoot regeneration was 23% from three independent experiments. Then, several shoots were excised, transferred onto MS basal medium supplemented with 3% sucrose and 0.8% agar at pH 5.8, and cultured in a growth chamber for 1 to 2 months. Roots were easily induced. Finally, plantlets carrying shoots and roots were transferred into soil, and all of them grew healthily in a greenhouse. No morphological variation was observed between the regenerated plantlets and the donor wild-type plants. In addition, we also established root cultures of W. chinensis in culture medium (MS medium, 3 mg/L NAA, 3% sucrose, pH 5.8) with or without 0.8% agar. To the best of our knowledge, this is the first paper reporting plant regeneration from leaf explants in the herbal plant W. chinensis.

Automated summary

This study reported the in vitro propagation of Wedelia chinensis using young leaf explants cultured in MS medium. Calli were induced in explants derived from the youngest top two leaves, with an average shoot regeneration rate of 23%. The plantlets were successfully transferred to soil, grew healthily, and showed no morphological variations.