Impact of Elevated CO2 and O3 Concentrations on Biogenic Volatile Organic Compounds Emissions from Ginkgo biloba

In natural environment with ambient air, ginkgo trees emitted volatile organic compounds 0.18 μg g⁻¹ h⁻¹ in July, and 0.92 μg g⁻¹ h⁻¹ in September. Isoprene and limonene were the most abundant detected compounds. In September, α-pinene accounted for 22.5% of the total. Elevated CO₂ concentration in OTCs increased isoprene emission significantly in July (p < 0.05) and September (p < 0.05), while the total monoterpenes emission was enhanced in July and decreased in September by elevated CO₂. Exposed to elevated O₃ increased the isoprene and monoterpenes emissions in July and September, and the total volatile organic compounds emission rates were 0.48 μg g⁻¹ h⁻¹ (in July) and 2.24 μg g⁻¹ h⁻¹ (in September), respectively. The combination of elevated CO₂ and O₃ did not have any effect on biogenic volatile organic compounds emissions, except increases of isoprene and Δ3-carene in September. Foundation item: The National Natural Science Foundation of China (No. 90411019).