Impact of rising CO sub(2) on emissions of volatile organic compounds: isoprene emission from Phragmites australis growing at elevated CO sub(2) in a natural carbon dioxide spring

Isoprene basal emission (the emission of isoprene from leaves exposed to a light intensity of 1000 mu mol m super(-2) s super(-1) and maintained at a temperature of 30 degree C) was measured in Phragmites australis plants growing under elevated CO sub(2) in the Bossoleto CO sub(2) spring at Rapolano...

Full description

Saved in:
Bibliographic Details
Published in:Plant, cell and environment cell and environment, 2004-04, Vol.27 (4), p.393-401
Main Authors: Scholefield, P A, Doick, K J, Herbert, B M, Hewitt, C N, Schnitzler, J, Pinelli, P, Loreto, F
Format: Article
Language:English
Subjects:
Freshwater
Phragmites australis
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Isoprene basal emission (the emission of isoprene from leaves exposed to a light intensity of 1000 mu mol m super(-2) s super(-1) and maintained at a temperature of 30 degree C) was measured in Phragmites australis plants growing under elevated CO sub(2) in the Bossoleto CO sub(2) spring at Rapolano Terme, Italy, and under ambient CO sub(2) at a nearby control site. Gas exchange and biochemical measurements were concurrently taken. Isoprene emission was lower in the plants growing at elevated CO sub(2) than in those growing at ambient CO sub(2). Isoprene emission and isoprene synthase activity (IsoS) were very low in plants growing at the bottom of the spring under very rich CO sub(2) and increased at increasing distance from the spring (and decreasing CO sub(2) concentration). Distance from the spring did not significantly affect photosynthesis making it therefore unlikely that there is carbon limitation to isoprene formation. The isoprene emission rate was very quickly reduced after rapid switches from elevated to ambient CO sub(2) in the gas-exchange cuvette, whereas it increased when switching from ambient to elevated CO sub(2). The rapidity of the response may be consistent with post-translational modifications of enzymes in the biosynthetic pathway of isoprene formation. Reduction of IsoS activity is interpreted as a long-term response. Basal emission of isoprene was not constant over the day but showed a diurnal course opposite to photosynthesis, with a peak during the hottest hours of the day, independent of stomatal conductance and probably dependent on external air temperature or temporary reduction of CO sub(2) concentration. The present experiments show that basal emission rate of isoprene is likely to be reduced under future elevated CO sub(2) levels and allow improvement in the modelling of future isoprene emission rates.
ISSN:0140-7791
1365-3040
DOI:10.1111/j.1365-3040.2003.01155.x