Effect of Intraspecific Competition and Substrate Type on Terpene Emissions from Some Mediterranean Plant Species

Abstract

Competition is an important factor that has been extensively reported in the Mediterranean area. There is evidence that leaf terpene accumulation may vary between plants growing on calcareous and siliceous soils. In the present study, leaf terpene emissions from potted seedlings of Pinus halepensis, Cistus albidus, and Quercus coccifera, growing under natural environmental conditions on calcareous and siliceous substrates, were studied by using a bag enclosure method. In both substrates, seedlings were potted alone and in intraspecific competition, to examine the effect of substrate type and that of intraspecific competition on terpene emissions. The results showed that competition favored: (i) overall monoterpene and sesquiterpene emissions from Q. coccifera; (ii) overall monoterpene emissions from P. halepensis; (iii) overall sesquiterpene emissions from C. albidus. Substrate type affected terpene emissions to a limited extent and in a species-specific way. Whereas for Q. coccifera, the overall monoterpene emissions and that of Allo-aromadendrene were favored on siliceous substrate, no significant changes were found in emissions from P. halepensis. Only the release of AR-curcumene from C. albidus was higher on siliceous substrate. We also found high variability in terpene emission composition from the study species, particularly for P. halepensis and Q. coccifera. These two species released both monoterpenes and sesquiterpenes, instead of monoterpenes only, as shown in previous studies.

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

“…In the case of Quercus suber, emissions of 15 different monoterpene species were found in our study, contrasting with other reports with only about 4 to 7 monoterpene species (Pio et al, 1993(Pio et al, , 2005Staudt et al, 2004;Staudt et al, 2008). Measurements of Rosmarinus officinalis confirmed the high variability of emissions as reported earlier (Hansen, et al, 1997;Seufert et al, 1997;Owen et al, 2002;Ormeno et al 2007aOrmeno et al , b, c, 2009Olivier et al, 2011).…”

“…Sesquiterpene emissions of Cistus albidus as low as 0.63 ± 0.32 µg g −1 h −1 were in concordance with Ormeno et al (2007a, d) but contrasted significantly higher emissions found in other studies (Llusia and Peñuelas, 1998;Ormeno et al, 2007b, c). We did not find any sesquiterpene emissions from Pinus halepensis and Rosmarinus officinalis, in contrast to observations reported by Ormeno et al (2007aOrmeno et al ( -d, 2009). The emission of (−)E−caryophyllene by Cistus monspeliensis disagrees with the findings by Llusia and Peñuelas (1998).…”

“…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.…”

“…The characterization of sesquiterpene emissions in the case of the Mediterranean area is sparse and only a few oaks, birches and pines typical for this region are reported to emit sesquiterpenes (Llusia and Peñuelas, 1998;Ciccioli et al, 1999;Hansen and Seufert, 1999;Ormeno et al, 2007b, d;Staudt and Lhoutellier, 2007;. In the course of our work on Mediterranean vegetation we found a high variability for these compounds in close accordance with other reports (Duhl et al, 2008;Llusia and Peñuelas, 1998;Ormeno et al, 2007aOrmeno et al, , b, c, d, 2009). Sesquiterpene emissions from Buxus sempervirens, Ceratonia siliqua and Olea europaea could be reported for the first time here.…”

“…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).…”