In Vitro Plant Regeneration via Adventitious Shoot Regeneration from Cotyledon and Leaf Explants of Diplocyclos Palmatus

ABSTRACT Micropropagation protocol for Diplocyclos palmatus through direct shoot induction from isolated cotyledon and leaf explants was established. Cotyledons were isolated from 2-week-old seedlings and cultured in the Murashige and Skoog (MS) medium supplemented with various concentrations of 6-benzylaminopurine (BAP, 0.5–2.0 mg L−1) alone or in combination with α-naphthalene acetic acid (NAA, 0.2–1.0 mg L−1) for shoot induction. The highest frequency of response (89%) and the mean number of shots (6.8) were observed in an MS medium supplemented with 1.5 mg L−1 BAP and 0.5 mg L−1 NAA. Leaves at various stages of development were isolated from in vitro grown shoots and cultured in an MS medium supplemented with different concentrations of BAP (0.5–2.5 mg L−1), Thidiazuron (TDZ, 0.5–2.5 mg L−1) alone and in combination with NAA (0.2 mg L−1) for shoot induction. The highest shoot induction frequency of 91% and shoot number of 7.8 shoots per explant were observed when 15-d-old- leaves were cultured in an MS medium enriched with 2.0 mg L−1 TDZ and 0.5 mg L−1 NAA after 45 d. The isolated cotyledon and leaf-derived shoots showed optimum rooting on ½ MS medium fortified with 4.0 mg L−1 indole-3-butyric acid (IBA). The rooted plants were transferred to the soil with 90% success.