TY - JOUR

T1 - On-line analysis of volatile organic compound emissions from Sitka spruce (Picea sitchensis).

AU - Hayward, Sean

AU - Tani, Akira

AU - Owen, Sue M.

AU - Hewitt, CN

PY - 2004/7

Y1 - 2004/7

N2 - Volatile organic compound (VOC) emissions from Sitka spruce (Picea sitchensis Bong.) growing in a range of controlled light and temperature regimes were monitored online with a proton transfer reaction–mass spectrometer (PTR–MS) operating at a temporal resolution of ~1 min. Isoprene emissions accounted for an average of more than 70% of measured VOCs and up to 3.5% of assimilated carbon. Emission rates (E) for isoprene correlated closely with photosynthetic photon flux (PPF) and temperature, showing saturation at a PPF of between 300 and 400 µmol m–2 s–1 and a maximum between 35 and 38 °C. Under standard conditions of 30 °C and 1000 µmol m–2 s–1 PPF, the mean isoprene E was 13 µg gdm–1 h–1, considerably higher than previously observed in this species. Mean E for acetaldehyde, methanol and monoterpenes at 30 °C were 0.37, 0.78 and 2.97 µg gdm–1 h–1, respectively. In response to a sudden light to dark transition, isoprene E decreased exponentially by > 98% over about 3 h; however, during the first 7 min, this otherwise steady decay was temporarily but immediately depressed to ~40% of the pre-darkness rate, before rallying during the following 7 min to rejoin the general downward trajectory of the exponential decay. The sudden sharp fall in isoprene E was mirrored by a burst in acetaldehyde E. The acetaldehyde E maximum coincided with the isoprene E minimum (7 min post-illumination), and ceased when isoprene emissions resumed their exponential decay. The causes of, and linkages between, these phenomena were investigated.

AB - Volatile organic compound (VOC) emissions from Sitka spruce (Picea sitchensis Bong.) growing in a range of controlled light and temperature regimes were monitored online with a proton transfer reaction–mass spectrometer (PTR–MS) operating at a temporal resolution of ~1 min. Isoprene emissions accounted for an average of more than 70% of measured VOCs and up to 3.5% of assimilated carbon. Emission rates (E) for isoprene correlated closely with photosynthetic photon flux (PPF) and temperature, showing saturation at a PPF of between 300 and 400 µmol m–2 s–1 and a maximum between 35 and 38 °C. Under standard conditions of 30 °C and 1000 µmol m–2 s–1 PPF, the mean isoprene E was 13 µg gdm–1 h–1, considerably higher than previously observed in this species. Mean E for acetaldehyde, methanol and monoterpenes at 30 °C were 0.37, 0.78 and 2.97 µg gdm–1 h–1, respectively. In response to a sudden light to dark transition, isoprene E decreased exponentially by > 98% over about 3 h; however, during the first 7 min, this otherwise steady decay was temporarily but immediately depressed to ~40% of the pre-darkness rate, before rallying during the following 7 min to rejoin the general downward trajectory of the exponential decay. The sudden sharp fall in isoprene E was mirrored by a burst in acetaldehyde E. The acetaldehyde E maximum coincided with the isoprene E minimum (7 min post-illumination), and ceased when isoprene emissions resumed their exponential decay. The causes of, and linkages between, these phenomena were investigated.

KW - acetaldehyde

KW - isoprene

KW - methanol

KW - monoterpenes

KW - post-illumination burst

KW - post-illumination depression

KW - PTR–MS

KW - pyruvate

KW - VOCs.

M3 - Journal article

VL - 24

SP - 721

EP - 728

JO - Tree Physiology

JF - Tree Physiology

SN - 1758-4469

IS - 7

ER -