Shoot organogenesis and plant regeneration in Cordia subcordata Lam

Cordia subcordata Lam. (Boraginaceae) is a woody tree that grows in coastal wasteland and mangrove edges. Its wood is used for woodcraft, and the tree, which is used in landscaping, also has medicinal and ecological value (e.g., coastal protection). In this study, a shoot proliferation and regeneration system was established for this plant. Callus was induced from terminal young leaf explants on Murashige and Skoog (MS) medium with 1.0 mg L-1 thidiazuron or 1.0 mg L-1 2,4-dichlorophenoxyacetic acid, or optimally with 0.5 or 1.0 mg L-1 of both. Callus differentiated from an average of 35.4% of explants into 3 to 5 adventitious shoots (indirect shoot organogenesis) within 45 d. Optimal shoot proliferation medium was MS medium with 0.8 mg L-1 6-benzyladenine (BA). A higher concentration of BA (1.5 mg L-1) in the presence of alpha-naphthaleneacetic acid (NAA) enhanced callus induction from the base of shoots and decreased shoot proliferation. On 1/2 MS medium with 0.5 mg L-1 NAA and/or indole-3-butyric acid, adventitious roots were induced from shoots. Within 1 mo, 95.4% of plantlets transferred to a substrate of vermiculite and peat (1:1, v/v) survived.