Sesquiterpene emissions from four chemotypes of Cinnamomum camphora in different seasons

Plant volatile terpenes bring various healthcare benefits to human during forest bathing. To uncover the dynamic emission characteristic and mechanism of sesquiterpenes from different chemotypes of Cinnamomum camphora during a year for promoting healthcare forest construction by using suitable chemotype and forest bathing in suitable season, the sesquiterpene constitutions and emission rate from camphor (CmR), linalool (LnL), eucalyptol (EuL) and borneol (BeL) chemotypes were investigated in May, July and November, and the related gene expression was analyzed. Among the four chemotypes, LnL released the maximum sesquiterpenes, including 18, 20 and 20 components in May, July and November, respectively, while CmR released the minimum sesquiterpenes, including 12, 13 and 10 components, respectively. In May and July, LnL showed the highest emission rate of total sesquiterpenes among the four chemotypes, with 796.12 and 3964.09 pmol·m −2 ·s −1 , respectively, which might be caused by high expression of 8 genes ( ACAT , HMGCS , HMGCR , MVK , E2.7.4.2 , MVD , FDFT1 , and GERD ) in mevalonate (MVA) pathway. In the four chemotypes, the variations of sesquiterpene emission rate during the three months were consistent with the alterations of temperature rather than other environmental factors (light intensity and relative humidity), and the highest sesquiterpene emission rate was found in July, which might result from high temperature up-regulating the genes in MVA pathway. Therefore, LnL should have greater potential to build healthcare forest due to the highest terpene emission rate, and the forest bathing should be carried out in hot season due to high temperature promoting terpene emission. • Four chemotypes of C. camphora released abundant sesquiterpenes but with differences. • The maximum emission was found in July due to the up-regulated genes in MVA pathway. • Linalool chemotype emitted the maximum sesquiterpenes by up-regulating related genes.