Interactive effect of UV radiation and CO2 treatment on extractable volatile organic compounds from European beech leaves

The main objective of this experiment was to investigate the combined effect of different UV treatments\nand elevated CO2 concentration on monoterpene and methyl salicylate (MES) content in leaves of\nEuropean beech during the growing season. Plants were grown under ambient (AC, 400 μmol mol–1) and\nelevated (EC, 700 μmol mol–1) CO2 concentrations and three UV radiation treatments (ambient – UVamb,\nexcluded – UV-, and enhanced – UV+). Leaves collected from July to September were extracted in cold\nheptane to determine volatile organic compounds content using gas chromatography. Our results show\nthat AC plants had higher total content of extractable monoterpenes and MES than did EC plants over\nthe whole growing season and irrespective of UV treatment. Limonene, 2-bornene, and ester MES were\nthe most abundant volatile compounds in beech leaves. The highest contents of 2-bornene and MES were\nfound under the UV- treatment and AC. Contents of α-pinene, β-pinene, and carene decreased during the\ngrowing season while the content of limonene increased