Field monoterpene emission of Mediterranean oak (Quercus ilex) in the central Iberian Peninsula measured by enclosure and micrometeorological techniques: Observation of drought stress effect

Abstract

[1] An experimental characterization of biogenic emission from Quercus ilex ssp. rotundifolia in a forest near Madrid, Spain, was carried out in the early autumn of the years [2000][2001][2002][2003]. A dynamic branch enclosure technique was implemented to determine the monoterpene emission rates of this evergreen oak species during the 2000 and 2001 campaigns. Major compounds emitted during both measurement periods were limonene, a-pinene, b-pinene, sabinene, and myrcene. In the 2000 field campaign the light-and temperature-dependent model of Guenther et al. [1993] did not fit the data due to drastic reductions of emission rates (and leaf gas exchange related parameters) observed at high air temperature and low air humidity (high water vapor pressure deficit). This plant physiological activity depletion and the subsequent emission reduction were attributed to severe water soil deficit conditions, as precipitation was very scarce during the growing season. In contrast, during the 2001 field campaign, neither emission nor physiological activity showed strong decreases in hot days. A good fit of experimental data to Guenther model was achieved in this field campaign (r 2 = 0.90), and linear regression gave a standard emission factor (E S ) of 14.0 mg gdw À1 h À1 (gdw is grams dry weight). Soil moisture was presumably higher than during the 2000 campaign due to recent rain events. With the purpose of documenting the drought stress effect at canopy level, monoterpene

Seasonal variations in terpene emission factors of dominant species in four ecosystems in NE Spain

“…The higher terpene emission rates in summer than in spring were also explained mostly by a large change in emission factor (capacity). Q. ilex is a strong emitter of terpenes, especially in warm summer conditions (Staudt and Seufert, 1995;Kesselmeier et al, 1996;Street et al, 1997;Holzinger et al, 2000;Llusia and Peñuelas, 2000;Loreto et al, 2001;Owen et al, 2001;Staudt et al, 2002;Plaza et al, 2005;Llusia et al, 2011). The Q. ilex monoterpene emission rates were 6.4 (3.7 for standardised values) times higher in summer than in spring, similar to reports of Llusia et al (2011) in a atypically warm and dry summer.…”

Process-based simulation of seasonality and drought stress in monoterpene emission models

“…Strong, long-lasting drought, however, decreases isoprenoid emissions considerably (Hansen et al, 1999;Pegoraro et al, 2004, Lavoir et al, 2009. Overall, an impact of summer drought on annual isoprenoid emission has frequently been observed (Geron et al, 1997;Plaza et al, 2005). A mechanistic understanding of isoprenoid responses to drought stress, however, has not yet been established.…”

Plant-soil interactions in Mediterranean forest and shrublands: impacts of climatic change

“…Additional effects on C-cycling and emissions of biogenic volatile organic compounds Drought usually increases emissions of plant terpenes, although this effect strongly depends on drought intensity (Pegoraro et al 2005;Plaza et al 2005;Llusia et al 2006Llusia et al , 2008Llusia et al , 2010. Studies suggest that severe drought decreases the emission of terpenes (Loreto et al 2001;Pegoraro et al 2007;Peñuelas and Staudt 2010) but reduces sink strength of the soil for atmospheric isoprene (Pegoraro et al 2007).…”