WITHDRAWN: Establishment of regeneration system from leaves wrapped by bud scales of Neolamarckia cadamba in the wild

Abstract

Neolamarckia cadamba is an evergreen tree species growing fast, with not only good wood properties, but also great value in medicine, feeding and landscape. In order to clone an excellent genotype individual of N. cadamba, the plant regeneration protocol was successfully established with leaves wrapped by bud scales in the wild as explants. The optimal sterilization method for the leaves was 0.1% HgCl2 treatment for 1 min before culturing on Murashige and Skoog’s (MS) medium supplemented with 3.0 mg/L thidiazuron (TDZ), 0.1 mg/L 2–4 dichlorophenoxyacetic acid (2-4D) and 0.05 mg/L α-naphthaleneacetic (NAA) acid to induce calluses. Additionally, the medium supplemented with 1 mL/L PPM could effectively inhibit the medium contamination without an unfavorable influence on the final induction rate of calluses from the leaves. Three types of calluses were induced from the leaves cultured on the above medium. Among them, only the emerald callus with bud points on its surface could differentiate into adventitious shoots on the MS medium supplemented with 1.5 mg/L 6–benzylaminopurine (6-BA) and 0.05 mg/L NAA, with the induction rate of 78.89%. The adventitious shoots were proliferated on the MS medium supplemented with 1.0 mg/L 6-BA and 0.05 mg/L indole-3- butyric acid (IBA). And the micro-shoots developed roots in the MS medium supplemented with 0.05 mg/L NAA and 0.05 mg/L IBA. The regeneration protocol can be used in the propagation and large scale production of seedlings with the same genotype as an excellent individual of N. cadamba in the wild.