Volatile organic compounds from Italian vegetation and their interaction with ozone

摘要

Volatile Organic Compounds (VOCs) emitted from vegetation (particularly isoprenoids) represent an important source of atmospheric hydrocarbons almost double the anthropogenic source. When biogenic VOC mix with NO_x in the presence of UV radiation, ozone (O_3) is formed. In Italy, optimal conditions for O_3 formation in terms of VOC/NO_x ratios and abundance of UV radiation occur for long periods of the year. Moreover, Italian vegetation includes several species that are strong and evergreen isoprenoid emitters, and high temperatures for part of the year further stimulate these temperature-dependent emissions. We review emission of isoprenoids from Italian vegetation, current knowledge on the impact of rising O_3 levels on isoprenoid emission, and evidence showing that isoprenoids can increase both the O_3 flux to the plant and protection against oxidative stress because of their antioxidant functions. This trait not only influences plant tolerance to O_3 but also may substantially alter the flux of O_3 between atmosphere and biosphere.