Leaf carotenoid concentrations and monoterpene emission capacity under acclimation of the light reactions of photosynthesis

Factors controlling the seasonal dynamics (days-weeks) in leaf monoterpene emission capacity are not yet well understood. Volatile isoprenoids, such as monoterpenes, and higher isoprenoids such as carotenoids share the initial steps of their synthesis pathways, therefore, interaction between the pool size of leaf carotenoids and its acclimation and leaf monoterpene emission capacity could be expected. Our aim was to examine this interaction in evergreen foliage using the non-storing Holm oak (Quercus ilex L.), as a model species. We modified the light environment of a number of potted trees in order to induce acclimation in leaf carotenoid contents, and study the effects on leaf monoterpene emission capacity. We followed chlorophyll fluorescence, photosynthetic capacity, chlorophyll and carotenoid contents, and monoterpene emission capacity. The results indicate that monoterpene emission capacity and photosynthetic pigment metabolism are coupled in Holm oak seedlings growing at or acclimating to different light levels.