Monoterpene and sesquiterpene emissions from <i>Quercus coccifera</i> exhibit interacting responses to light and temperature

Abstract

Abstract. Light and temperature are known to be the most important environmental factors controlling biogenic volatile organic compound (BVOC) emissions from plants, but little is known about their interdependencies especially for BVOCs other than isoprene. We studied light responses at different temperatures and temperature responses at different light levels of foliar BVOC emissions, photosynthesis and chlorophyll fluorescence on Quercus coccifera, an evergreen oak widespread in Mediterranean shrublands. More than 50 BVOCs were detected in the emissions from Q. coccifera leaves most of them being isoprenoids plus a few green leaf volatiles (GLVs). Under standard conditions non-oxygenated monoterpenes (MT-hc) accounted for about 90 % of the total BVOC release (mean ± SD: 738 ± 378 ng m −2 projected leaf area s −1 or 13.1 ± 6.9 µg g −1 leaf dry weight h −1 ) and oxygenated monoterpenes (MT-ox) and sesquiterpenes (SQTs) accounted for the rest in about equal proportions. Except GLVs, emissions of all BVOCs responded positively to light and temperature. The light responses of MT and SQT emissions resembled that of CO 2 -assimilation and were little influenced by the assay temperature: at high assay temperature, MT-hc emissions saturated at lower light levels than at standard assay temperature and tended even to decrease in the highest light range. The emission responses to temperature showed mostly Arrhenius-type response curves, whose shapes in the high temperature range were clearly affected by the assay light level and were markedly different between isoprenoid classes: at non-saturating light, all isoprenoids showed a similar temperature optimum (∼43 • C), but, at higher temperatures, MT-hc emissions decreased faster than MT-ox and SQT emissions. At saturating light, MT-hc emissions peaked around 37 • C and rapidly dropped at higher temperatures, whereas MT-ox and SQT emissions strongly Correspondence to: M. Staudt (michael.staudt@cefe.cnrs.fr) increased between 40 and 50 • C accompanied by a burst of GLVs. In all experiments, decreases of MT-hc emissions under high temperatures were correlated with decreases in CO 2 -assimilation and/or photosynthetic electron transport. We conclude that light and temperature can have interactive short-term effects on the quantity and quality of BVOC emissions from Q. coccifera through substrate limitations of MT biosynthesis occurring at temperatures supraoptimal for photosynthetic processes that are exacerbated by oxidative stress and membrane damages. Such interactive effects are likely to occur frequently during hot and dry summers and simulations made in this work showed that they may have important consequences for emission predictions.

Leaf level emissions of volatile organic compounds (VOC) from some Amazonian and Mediterranean plants

“…Sesquiterpene emissions from Quercus coccifera were quantitatively but not qualitatively comparable. We found only (−)E-caryophyllene emissions, whereas a variety of sesquiterpene species were reported in other studies (Ormeno et al, 2007a(Ormeno et al, , c, d, 2009Staudt and Lhoutellier, 2011). It is important to note that for Cistus albidus most of the sesquiterpene species identified here were partially in accordance with other studies performed in the Mediterranean region (Llusia and Peñuelas, 1998;Ormeno et al, 2007a, b, c, d) except for emissions of α-and ß-cubebene.…”

“…Observed monoterpene emission rates were quantitatively comparable to literature data in a few cases only, e.g. for Ceratonia siliqua, Pinus halepensis, Quercus coccifera and Rosmarinus officinalis (Llusia and Peñuelas, 2000;Owen et al, 2001;Ormeno et al, 2007aOrmeno et al, , b, c, 2009Staudt and Lhoutellier, 2011). Quercus suber has been identified previously as a non-isoprenoid-emitter tree Steinbrecher et al, 1997).…”

“…Sesquiterpene emissions are known to be induced by a variety of stresses, including heat and oxidative stress (Loreto and Schnitzler, 2010;Holopainen and Gershenzon, 2010). For example in a recent study on Quercus coccifera, Staudt and Lhoutellier (2011) observed that sesquiterpene emissions became boosted during exposure to heat and high radiation, while at moderate temperatures sesquiterpene emissions were low or even undetectable in this species. In line with this, field studies by Ormeno et al (2007dOrmeno et al ( , 2009) observed the highest standard emissions of Rosmarinus officinalis in June, whereas lower emission rates were found in March or January, suggesting a seasonal trend possibly associated with heat and oxidative stress occurring under Mediterranean summer conditions.…”

Diel cycles of isoprenoids in the emissions of Norway spruce, four Scots pine chemotypes, and in Boreal forest ambient air during HUMPPA-COPEC-2010

“…Singsaas et al, 1997;Loreto et al, 1998;Copolovici et al, 2005), but our data confirms the previously noted strong temperature dependency of sesquiterpene emissions from Scots pine in field conditions (e.g. Staudt and Lhoutellier, 2011;Jardine et al, 2011). It has been noted previously that the temperature dependence factor for sesquiterpenes (beta in the Guenther emission algorithm) is higher than that of monoterpenes for many pine trees (Helmig et al, 2007).…”

Ozone stress as a driving force of sesquiterpene emissions: a suggested parameterisation

“…5) that SQT emission responses to temperature can attenuate under higher ozone concentrations. This trend has already been hypothesized by Staudt et al (2011), according to whom it is most likely that other environmental factors such as drought, ozone and CO 2 concentrations can amplify or attenuate such alterations in the emission responses to temperature. An empirical formulation of SQT emissions, such the one that we suggest, cannot explain all the details of the emission profile of these compounds but it broadens our understanding in the tree responses under natural conditions.…”