Relation of leaf terpene contents to terpene emission profiles in Japanese cedar (Cryptomeria japonica).

Plants protect themselves against various stresses by using volatile terpenes, which are also key precursors of climate‐relevant constituents in the atmosphere. Conifers store terpenes in storage pools, which serve as emission sources. However, how leaf terpene contents influence the quantity and composition of emissions is uncertain. Here, we examined whether they explain the profile of terpene emissions by using the measurements of 6 monoterpenes and 2 diterpenes stored in and emitted from the same branches of 10 local populations in Japanese cedar (Cryptomeria japonica), a common conifer in Japan. We estimated partial pressures of terpenes from leaf terpene contents by using a thermodynamic algorithm. The estimates correlated well with emissions of monoterpenes, suggesting the release of monoterpenes from the storage pools. High tree‐to‐tree variations in emissions of individual terpenes did not correlate with variations in concentrations of corresponding terpenes in leaves. Diterpenes (ent‐kaurene and phyllocladene) were emitted in most cases when individual trees held corresponding diterpenes, suggesting a linkage between emissions and storage pools, but the emissions were not explained by the algorithm owing to their low vapor pressure. [ABSTRACT FROM AUTHOR]