Volatile organic compounds emissions in Norway spruce (Picea abies) in response to temperature changes

Volatile organic compound (VOC) emissions from Norway spruce (Picea abies) saplings were monitored in response to a temperature ramp. Online measurements were made with a proton transfer reaction - mass spectrometer under controlled conditions, together with plant physiological variables. Masses corresponding to acetic acid and acetone were the most emitted VOCs. The emission rates of m137 (monoterpenes), m59 (acetone), m33 (methanol), m83 (hexanal, hexenals), m85 (hexanol) and m153 (methyl salicylate, MeSa) increased exponentially with temperature. The emission of m61 (acetic acid) and m45 (acetaldehyde), however, increased with temperature only until saturation around 30 degrees C, closely following the pattern of transpiration rates. These results indicate that algorithms that use only incident irradiance and leaf temperature as drivers to predict VOC emission rates may be inadequate for VOCs with lower H, and consequently higher sensitivity to stomatal conductance