Bartolome J, Peñuelas J, Filella I, Llusià J, Broncano MJ, Plaixats J (2007) Mass scans from a proton transfer mass spectrometry analysis of air over Mediterranean shrubland browsed by horses. Journal Environmental Biologi 28: 697-700
Peñuelas J, Sardans J, Stefanescu C, Parella T, Filella I (2007) Transferencia de defenses de les plantes als herbívors. UAB DIVULGA 05/2007.
Peñuelas J., Estiarte M, Ogaya R, Filella I, Jump A, Garbulsky M, Sardans J., Llusià J, Seco R, Alessio G., Hunt J, Owen S, Asensio D, Prieto P, Ribas A, Carrillo B, Blanch S, Coll M, Kefauer S, Stefanescu C, Lloret F, Terradas J (2007) Climate change effects on Mediterranean forests: from observations to experimentation, from genetics to remote sensing. Afforestation and sustainable forests as means to combat desertification. 16-19 April Jerusalem, Israel, p. 50.
Peñuelas J., Llusià J., Filella I. (2007) Methyl salicylate fumigation increases monoterpene emission rates. Biologia Plantarum. 51: 372-376.LinkDoi: 10.1007/s10535-007-0078-9
We aimed to assess the potential effects of fumigation by methyl salicylate (MeSA) on plant monoterpene production and emissions. We evaluated monoterpene production and emissions both by chromatographic and proton transfer reaction mass spectrometry at the whole plant-and leaf-scales, in MeSa-fumigated (ca. 60 mm3 m-3 in air) and control (without MeSa fumigation) holm oak (Quercus ilex L.) plants exposed to temperatures ranging from 25 to 50 °C. The MeSa-fumigated plants showed ca. 3-4-fold greater leaf monoterpene concentrations and emission rates than the control plants between the temperatures of 25 to 45 °C. © 2007 Institute of Experimental Botany, ASCR.
Seco R., Peñuelas J., Filella I. (2007) Short-chain oxygenated VOCs: Emission and uptake by plants and atmospheric sources, sinks, and concentrations. Atmospheric Environment. 41: 2477-2499.LinkDoi: 10.1016/j.atmosenv.2006.11.029
Emissions of volatile organic compounds (VOCs) have multiple atmospheric implications and play many roles in plant physiology and ecology. Among these VOCs, growing interest is being devoted to a group of short-chain oxygenated VOCs (oxVOCs). Technology improvements such as proton transfer reaction-mass spectrometry are facilitating the study of these hydrocarbons and new data regarding these compounds is continuously appearing. Here we review current knowledge of the emissions of these oxVOCs by plants and the factors that control them, and also provide an overview of sources, sinks, and concentrations found in the atmosphere. The oxVOCs reviewed here are formic and acetic acids, acetone, formaldehyde, acetaldehyde, methanol, and ethanol. In general, because of their water solubility (low gas-liquid partitioning coefficient), the plant-atmosphere exchange is stomatal-dependent, although it can also take place via the cuticle. This exchange is also determined by atmospheric mixing ratios. These compounds have relatively long atmospheric half-lives and reach considerable concentrations in the atmosphere in the range of ppbv. Likewise, under non-stressed conditions plants can emit all of these oxVOCs together at fluxes ranging from 0.2 up to 4.8 μg(C)g-1(leaf dry weight)h-1 and at rates that increase several-fold when under stress. Gaps in our knowledge regarding the processes involved in the synthesis, emission, uptake, and atmospheric reactivity of oxVOCs precludes the clarification of exactly what is conditioning plant-atmosphere exchange-and also when, how, and why this occurs-and these lacunae therefore warrant further research in this field. © 2006 Elsevier Ltd. All rights reserved.
Filella I., Peñuelas J. (2006) Daily, weekly, and seasonal time courses of VOC concentrations in a semi-urban area near Barcelona. Atmospheric Environment. 40: 7752-7769.LinkDoi: 10.1016/j.atmosenv.2006.08.002
In order to study the daily, weekly, and seasonal patterns and possible origins of air concentrations of volatile organic compounds (VOCs), measurements were taken on a minute-by-minute basis with a PTR-MS in the vicinity of a highway in a semi-urban site near Barcelona. Four periods of the year were chosen and samples were taken under different meteorological conditions and at different phenological stages of the surrounding vegetation. None of the measured VOCs concentrations exceeded air-quality guidelines. The results showed that diurnal, weekly, and seasonal fluctuations in measured VOC concentrations depended on variations in the strength of sources, as well as on photochemical activity and meteorological conditions. There was a decrease in concentrations in most VOCs when mixing depth, photochemical destruction, and wind speed increased at midday. On the other hand, high values of some VOCs occurred at night when the strength of their sinks and the mixing layer decreased. Interestingly, in June, night emissions and concentration peaks of methanol and acetone occurred in periods with dew formation and no wind. VOCs related to anthropogenic emissions presented a weekly pattern of variation with a clear distinction being found between working days and the weekend. The seasonal variation showed higher levels in December for all VOCs, except for isoprene. The thinning of the mixing layer leading to greater concentrations of volatiles and lower wind speeds in winter could account for those higher VOC levels. Benzene and toluene originated mainly from anthropogenic emissions. The sources of acetaldehyde, methanol, and acetone appeared to be mainly biogenic and these compounds were the most abundant of all the measured VOCs. Isoprene concentration patterns suggest a predominantly anthropogenic origin in December and March and a mainly biogenic origin in June and October. All these data provide useful information on the dynamics of VOCs in an area where ozone levels in summer exceed quite often the standard protection thresholds for O3. © 2006 Elsevier Ltd. All rights reserved.
Filella I., Peñuelas J. (2006) Daily, weekly and seasonal relationships among VOCs, NOx and O3in a semi-urban area near Barcelona. Journal of Atmospheric Chemistry. 54: 189-201.LinkDoi: 10.1007/s10874-006-9032-z
Daily, weekly, and seasonal patterns of O3, NOx and VOCs and their relationship to meteorological conditions were studied in a semi-urban site near Barcelona by means of five-day long campaigns that included weekend and labor days in December, March, June, and October. The plant protection thresholds for ozone and NO2 were exceeded, respectively, on all the studied days in summer and on all the studied days. Ozone formation was predominantly local and relied on photochemical processes with VOCs playing a controlling role. Formaldehyde, acetaldehyde, methanol, toluene, isoprene, and acetone (in this order) presented the highest O3 formation potential during the studied periods. These results highlight the important role in O3 formation played by VOC species such as acetaldehyde, methanol, and acetone, that all have a significant biogenic component. Thus, these VOCs must be taken into account in the discussion of any ozone abatement strategy. © Springer Science+Business Media, B.V. 2006.
Filella I., Peñuelas J., Llusià J. (2006) Dynamics of the enhanced emissions of monoterpenes and methyl salicylate, and decreased uptake of formaldehyde, by Quercus ilex leaves after application of jasmonic acid. New Phytologist. 169: 135-144.LinkDoi: 10.1111/j.1469-8137.2005.01570.x
• Jasmonic acid (JA) is a signalling compound with a key role in both stress and development in plants, and is reported to elicit the emission of volatile organic compounds (VOCs). Here we studied the dynamics of such emissions and the linkage with photosynthetic rates and stomatal conductance. • We sprayed JA on leaves of the Mediterranean tree species Quercus ilex and measured the photosynthetic rates, stomatal conductances, and emissions and uptake of VOCs using proton transfer reaction mass spectrometry and gas chromatography after a dark-light transition. • Jasmonic acid treatment delayed the induction of photosynthesis and stomatal conductance by approx. 20 min, and decreased them 24 h after spraying. Indications were found of both stomatal and nonstomatal limitations of photosynthesis. Monoterpene emissions were enhanced (20-30%) after JA spraying. Jasmonic acid also increased methyl salicylate (MeSa) emissions (more than twofold) 1 h after treatment, although after 24 h this effect had disappeared. Formaldehyde foliar uptake decreased significantly 24 h after JA treatment. • Both biotic and abiotic stresses can thus affect plant VOC emissions through their strong impact on JA levels. Jasmonic acid-mediated increases in monoterpene and MeSa emissions might have a protective role when confronting biotic and abiotic stresses. © New Phytologist (2005).
Menzel A, Sparks TH, Estrella N, Koch E, Aasa A, Ahas R, Alm-Kübler K, Bissolli P, Braslavská O, Briede A, Chmielewski FM, Crepinsek Z, Curnel Y, Dahl A, Defila C, Donnelly A, Filella I, Jatczak K, Mage F, Mestre A, Nordli O, Peñuelas J et al. (2006) European phenological response to climate change matches the warming pattern. Global Change Biology 12: 1969-1976
Peñuelas J., Sardans J., Stefanescu C., Parella T., Filella I. (2006) Lonicera implexa leaves bearing naturally laid eggs of the specialist herbivore Euphydryas aurinia have dramatically greater concentrations of iridoid glycosides than other leaves. Journal of Chemical Ecology. 32: 1925-1933.LinkDoi: 10.1007/s10886-006-9118-8
We tested in the field the hypothesis that the specialist butterfly Euphydryas aurinia (Lepidoptera: Nymphalidae, Melitaeinae) lays eggs on leaves of Lonicera implexa (Caprifoliaceae) plants with greater iridoid concentrations. We conducted our investigations in a Mediterranean site by analyzing leaves with and without naturally laid egg clusters. There were no significant differences in iridoid glycoside concentrations between leaves from plants that did not receive eggs and the unused leaves from plants receiving eggs, a fact that would seem to indicate that E. aurinia butterflies do not choose plants for oviposition by their iridoid content. However, the leaves of L. implexa that bore egg clusters had dramatically greater (over 15-fold) concentrations of iridoid glycosides than the directly opposite leaves on the same plant. These huge foliar concentrations of iridoids (15% leaf dry weight) may provide specialist herbivores with compounds that they either sequester for their own defense or use as a means of avoiding competition for food from generalist herbivores. Nevertheless, it may still be possible that these high concentrations are detrimental to the herbivore, even if the herbivore is a specialist feeder on the plant. © Springer Science + Business Media, Inc. 2006.
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