2018 Volume 74 Issue 3 Pages 102-108
Tropospheric ozone (O3) concentration has been increasing. The aim of this study was to compare the effect of O3 exposure on monoterpene emission rate and the components of Japanese cedar (Cryptomeria japonica) between three major gene pools identified by population genetic structure analysis. At the O3-FACE (Free-Air O3 and CO2 Enrichment) facility, 1-year saplings of three clones of Japanese cedar (Donden, Kawazu, and Yakushima) were exposed to ambient double concentrations of O3. After 15 months of O3 exposure experiment, monoterpene emission characteristics were evaluated by branch enclosure method using cutting samples of current-year leaves. Basal biogenic volatile organic compound emission rate (Es) was higher in the O3 exposure plots, and two-way analysis of variance revealed an effect of the O3 exposure (p<0.05) and an interaction between the O3 exposure and clone (p<0.05). Especially, high Es values were observed in the Yakushima after the O3 exposure. In addition, the coefficient β related to temperature sensitivity increased in the O3 exposure plots (p<0.05). Our findings supported the fact that there are large inter-clone variations in C. japonica. It is important to evaluate the differences in clones considering the genetic diversity and to clarify the mechanism of the differences after long-term moderate O3 exposure.