ISSN 1021-4437, Russian Journal of Plant Physiology, 2009, Vol. 56, No. 1, pp. 29–37. © Pleiades Publishing, Ltd., 2008.
Published in Russian in Fiziologiya Rastenii, 2009, Vol. 56, No. 1, pp. 35–45.
Climatic studies of the Mediterranean region in
northeastern Spain have shown a trend of increasing
temperature and soil drought in the last decades [1, 2].
It is likely that the warmer and drier weather and the
droughts will persist in the near future [3–5] with the
possibility of having signiﬁcant effects on vegetation
[2, 5, 6], including their isoprenoid emission rates [7, 8].
Volatile isoprenoids are produced by many plant tis-
sues and during various physiological processes.
Recent advances in molecular and genetic techniques
and development of new instrumentation for the collec-
tion and analysis of these volatile isoprenoids have
increased our knowledge for their nature and function.
In some plants, they accumulate in specialized organs
in leaves and stems and can be released as deterrents
against pathogens and herbivores or to aid wound seal-
ing after damage. In other plants, volatile isoprenoids
are not stored, being emitted after production. They
seem to attract pollinators and herbivore predators, and
to communicate with other organisms . Another pos-
sible function of isoprenoids like isoprene is the dissi-
The text was submitted by the authors in English.
pation of excessive energy . The release of the bio-
genic isoprene has also been considered a manifesta-
tion of excretory function of the leaf and a result of
carbon conversions in a chain of photosynthetic reac-
tions under stressful conditions . But in the frame
of current climate warming, recently some evidence
has emerged that the production and emission of iso-
prene and monoterpenes, which constitute a major frac-
tion of biogenic volatile organic compounds, might
confer plant protection against high temperatures
or/and oxidative stress [12–15] or even the ecosystem
Plant isoprenoid emission rates are altered by water
availability, for example, decrease in response to mod-
erate drought conditions [16, 17]. They also respond to
temperature [8, 14, 18, 19] and seasonality [17, 19, 20].
Temperature increases the production and emission
rates of most terpenes exponentially up to the maxi-
mum by enhancing the synthetic activities, raising the
terpene vapor pressure, and decreasing the resistance of
emission pathway [7, 21, 22].
However, the effects of soil drought and warming on
isoprenoid emission rates are still not well known, par-
ticularly the response of species and compound compo-
Net Ecosystem Exchange and Whole Plant Isoprenoid Emissions
by a Mediterranean Shrubland Exposed to Experimental
J. Llusià, J. Penuelas, P. Prieto, and M. Estiarte
Unitat d’Ecoﬁsiologia CSIC-CEAB-CREAF, Centre de Recerca Ecològica i Aplicacions Forestals, Ediﬁci C, Universitat
Autònoma de Barcelona, E-08193 Bellaterra, Barcelona, Spain; fax: 34-93-581-41-51,
Received July 4, 2007
— We tested the effect of forecasted soil drought and warming climate conditions for the next decades
on emission rates of isoprenoids by mediterranean shrublands. We measured isoprenoid emissions by whole
dominant mediterranean woody plants (
L.) inhabiting the studied
shrublands. Monoterpene emissions were detected in both species, but isoprene was emitted only by
Maximum emission rates were found during the hottest periods (except for
, in which they
occurred in autumn), and minimum emission rates in winter in
Terpene emission rates ranged
g/(g dry wt h) in winter in
g/(g dry wt h) in
in autumn. In
, the terpene emission rates decreased in response to soil drought only in summer, but increased in
response to warming in spring and autumn. Isoprene emissions ranged from 0.1
g/(g dry wt h) in spring to
g/(g dry wt h) in summer. The effect of the treatments was only detected in autumn when soil drought and
warming had a negative effect on isoprene emission rates. These data might improve our knowledge of iso-
prenoid emissions at the canopy level and in response to climate change, soil drought, or warming.
Key words: Erica multiﬂora - Globularia alypum - emission rate - isoprenoids - terpenes - climate change - soil
drought - warming