A micropropagation protocol for Cinnamomum camphora

A micropropagation protocol was developed for Cinnamomum camphora (L.) Sieb., using as initial explants 3-5-mm shoot tips from newly emerged laterals of 2-yr-old trees. Performance of small shoot tips was compared with that of 2.0-cm nodal segments during subculture. Murashige and Skoog medium (MS) supplemented with different concentrations of N₆-benzyladenine (BA) or thidiazuron (TDZ) was used to examine shoot proliferation. In separate experiments, MS was supplemented with 1-naphthaleneacetic acid (NAA) for rooting of shoots, and the commercial preparation EM₂ for prevention of hyperhydricity. BA stimulated shoot formation and callus development, whereas TDZ promoted only callus development. Both cytokinins induced hyperhydricity when small shoot tips were used, with severity being directly related to concentrations. Hyperhydricity was avoided in subcultures by using larger nodal segments. EM₂ did not alter degree of hyperhydricity but suppressed callus development and strongly promoted shoot multiplication. The number of new shoots after a 6-wk subculture was 9 per nodal segment when supplemented solely with 4.4 μM BA and 18 per segment when further supplemented with 1000 mg EM₂ per l. Rooting of shoots occurred best when supplemented solely with 0.54 μM NAA, averaging 7 roots per shoot in 4 wk. Ninety percent of rooted shoots survived transfer to the greenhouse.