Variations in the terpenoid composition of naturally grown <i>Lindera umbellata</i> var. <i>membranacea</i> trees with different bark thicknesses

Abstract To clarify the variations in terpenoid composition due to bark development, bark extracts from three trees of Lindera umbellata var. membranacea were analyzed. Stem discs were collected at different heights from two trees (A and B) to assess the variation in terpenoid composition relative to bark thickness. The remaining tree (C) was used to examine radial variations in terpenoid composition from the inner bark to the periderm. Terpenoid composition and the enantiomeric ratio of linalool were analyzed using gas chromatography-mass spectrometry and gas chromatography-flame ionization detection. The terpenoid composition of the bark changed during bark development, and these terpenoid proportion changed with increasing bark thickness. The ratios of terpinen-4-ol, bornyl acetate, and β -bisabolene in trees A and B, and those of α -pinene, camphene, β -pinene, 3-carene, limonene, 1,8-cineole, α -terpineol, and caryophyllene in tree B tended to increase with increasing bark thickness. Furthermore, the peak areas of 1,8-cineole and terpinen-4-ol in the bark of tree C increased as the phloem thickness increased. Additionally, the enantiomeric ratio of linalool varied with the inner bark development of tree C. Obtained results suggested that the terpenoids detected in this study provide a defensive function against wounding, especially in the phloem of L. umbellata var. membranacea .