Abstract

Thidiazuron (TDZ) was more effective than 6-benzyladenine (6-BA) for adventitious shoot induction from mature seeds of Phellodendron amurense Rupr. Explants of hypocotyl + cotyledon produced more adventitious shoots than explants of cotyledon alone. Water rinsing pretreatment of dehusked seeds, optimally for two or three days, shortened the adventitious shoot induction period to 5 days. Adventitious shoot induction frequency (91.8%) and shoot number per explant (38.4) were highest on Murashige and Skoog (1962) medium (MS) with 1.0 mg/L TDZ and 0.2 mg/L a-naphthaleneacetic acid. Histological investigations indicated that adventitious shoots were induced directly from hypocotyl endodermal cells. 6-BA was more effective than TDZ for adventitious shoot elongation. Rooting frequency was highest (85%) with 1.0 mg/L indole-3-butyric acid. The rapid and high frequency adventitious shoot induction and plant regeneration method that we developed may be useful in future studies on Agrobacterium-mediated genetic transformation of P. amurense.

Key words: Phellodendron amurense, mature embryo, direct organogenesis, thidiazuron, ploidy analysis.