Blanch J.-S., Peñuelas J., Sardans J., Llusià J. (2009) Drought, warming and soil fertilization effects on leaf volatile terpene concentrations in Pinus halepensis and Quercus ilex. Acta Physiologiae Plantarum. 31: 207-218.LinkDoi: 10.1007/s11738-008-0221-z
The changes in foliar concentrations of volatile terpenes in response to water stress, fertilization and temperature were analyzed in Pinus halepensis and Quercus ilex. The most abundant terpenes found in both species were α-pinene and Δ3-carene. β-Pinene and myrcene were also abundant in both species. P. halepensis concentrations were much greater than those of Q. ilex in agreement with the lack of storage in the latter species (15205.60 ± 1140.04 vs. 0.54 ± 0.08 μg g-1 [d.m.]). The drought treatment (reduction to 1/3 of full watering) significantly increased the total terpene concentrations in both species (54% in P. halepensis and 119% in Q. ilex). The fertilization treatment (addition of either 250 kg N ha-1 or 250 kg P ha-1 or both) had no significant effects on terpene foliar concentrations. The terpene concentrations increased from 0.25 μg g-1 [d.m.] at 30°C to 0.70 μg g-1 [d.m.] at 40°C in Q. ilex (the non-storing species) and from 2,240 μg g-1 [d.m.] at 30°C to 15,621 μg g-1 [d.m.] at 40°C in P. halepensis (the storing species). Both species presented negative relationship between terpene concentrations and relative water contents (RWC). The results of this study show that higher terpene concentrations can be expected in the warmer and drier conditions predicted for the next decades in the Mediterranean region. © 2008 Franciszek Górski Institute of Plant Physiology, Polish Academy of Sciences.
Porcar-Castell A, Peñuelas J, Owen SM, Llusià J, Munné-Bosch S, Bäck J (2009) Leaf carotenoid concentrations and monoterpene emission capacity under acclimation of the light reactions of photosysnthesis. Boreal Environment Research 14: 794-806.
Prieto P, Peñuelas J, Llusià J, Asensio D, Estiarte M (2009) Effects of long-term experimental night-time warming and drought on photosynthesis, Fv/Fm and stomatal conductance in the dominant species of a Mediterranean shrubland. Acta Physiol Plant doi: 10.1007/s11738-009-0285-4. 31: 729-739.
Peñuelas J, Sardans J, Llusià J, Owen SM, Carnicer J, Giambelluca TW, Rezende EL, Mashuri Waite, Niinemets Ü (2009) Faster returns on ‘leaf economics’ and different biogeochemical niche in invasive compared with native plant species. Global Change Biology doi: 10.1111/j.1365-2486.2009.02054.x.
Llorens L., Llusià J., Murchie E.H., Peñuelas J., Beerling D.J. (2009) Monoterpene emissions and photoinhibition of "living fossil" trees grown under CO2 enrichment in a simulated Cretaceous polar environment. Journal of Geophysical Research: Biogeosciences. 114: 0-0.LinkDoi: 10.1029/2008JG000802
Polar forests populated high-latitude landmasses during the Cretaceous and early Paleogene when the climate was warm and the atmospheric CO2 concentration ([CO2]) was at least double that of the present-day. We investigated emission rates and composition of monoterpenes in relation to photoinhibition and photoprotection of two evergreen and three deciduous "living fossil" tree species representative of these ancient forests, after growth in a simulated Cretaceous polar (75°N) environment at either ambient (400 ppm) or elevated (800 ppm) [CO2] for four years. Total monoterpene emission rates peaked during the polar summer, when prolonged periods of 24 h light would have been conducive to enhancing the formation and chemical lifetime of ozone, and hence its radiative forcing. During most of the growing season, a-pinene was the main compound emitted, although the magnitude and chemical speciation of emissions was highly species specific. Growth at elevated [CO2] changed the composition of monoterpene emissions in evergreen and deciduous species, but only altered total leafscale emission rates of the deciduous species. The continuous daylight (photon flux: 300400 μmol PAR m-2 s-1) of the simulated polar summer (14.5 weeks) did not result in leaf photoinhibition or increased photoprotection via the xanthophyll cycle. Nevertheless, species with high a-pinene emission* rates showed also high values of photochemical efficiency at ambient [CO 2], suggesting a possible function of this monoterpene in protecting the photosynthetic apparatus. We suggest that high monoterpene emissions from forests during the long polar summers may constitute a regional high-latitude climatic feedback through alteration of tropospheric composition, and secondary organic aerosol formation. These biotic effects may be important to represent in Earth system models of ancient "greenhouse" climates. Copyright 2009 by the American Geophysical Union.
Llusià J., Penuelas J., Prieto P., Estiarte M. (2009) Net ecosystem exchange and whole plant isoprenoid emissions by a mediterranean shrubland exposed to experimental climate change. Russian Journal of Plant Physiology. 56: 29-37.LinkDoi: 10.1134/S1021443709010051
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 (Erica multiflora L. and Globularia alypum L.) inhabiting the studied shrublands. Monoterpene emissions were detected in both species, but isoprene was emitted only by E. multiflora. Maximum emission rates were found during the hottest periods (except for G. alypum, in which they occurred in autumn), and minimum emission rates in winter in E. multiflora. Terpene emission rates ranged from 0.08 μg/(g dry wt h) in winter in E. multiflora to 8.8 μg/(g dry wt h) in G. alypum in autumn. In E. multiflora, 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 μg/(g dry wt h) in spring to 4.4 μg/(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 isoprenoid emissions at the canopy level and in response to climate change, soil drought, or warming. © 2008 MAIK Nauka.
Peñuelas J., Filella I., Seco R., Llusià J. (2009) Increase in isoprene and monoterpene emissions after re-watering of droughted Quercus ilex seedlings. Biologia Plantarum. 53: 351-354.LinkDoi: 10.1007/s10535-009-0065-4
We followed the diurnal cycles of isoprenoid emissions from Quercus ilex seedlings under drought and after re-watering. We found that Quercus ilex, generally considered a non-isoprene emitter, also emitted isoprene although at low rates. The emission rates of isoprene reached 0.37 ± 0.02 nmol m-2 s-1 in controls, 0.15 ± 0.03 nmol m-2 s-1 under drought and 0.35 ± 0.04 nmol m-2 s-1 after re-watering, while emission rates of monoterpenes reached 11.0 ± 3.0, 7.0 ± 1.0 and 23.0 ± 5.0 nmol m-2 s-1, respectively. Emission rates recovered faster after re-watering than photosynthetic rate and followed diurnal changes in irradiance in controls and under drought, but in leaf temperature after re-watering. © 2009 Springer Science+Business Media B.V.
Prieto P., Peñuelas J., Llusià J., Asensio D., Estiarte M. (2009) Effects of experimental warming and drought on biomass accumulation in a Mediterranean shrubland. Plant Ecology. 205: 179-191.LinkDoi: 10.1007/s11258-009-9608-1
We studied the effects of experimental warming and drought on the plant biomass of a Mediterranean shrubland. We monitored growth at plant level and biomass accumulation at stand level. The experimentation period stretched over 7 years (1999-2005) and we focused on the two dominant shrub species, Erica multiflora L. and Globularia alypum L. and the tree species Pinus halepensis L. The warming treatment increased shoot elongation in E. multiflora, and the drought treatment reduced shoot elongation in G. alypum. The elongation of P. halepensis remained unaffected under both treatments. The balance between the patterns observed in biomass accumulation for the three studied species in the drought plots (reduction in E. multiflora and P. halepensis and increase in G. alypum) resulted in a trend to reduce 33% the biomass of the drought treatment plots with respect to the untreated plots, which almost doubled their biomass from 1998 to 2005. The results also suggest that under drier conditions larger accumulation of dead biomass may occur at stand level, which combined with higher temperatures, may thus increase fire risk in the Mediterranean area. © Springer Science+Business Media B.V. 2009.
Pérez-Rial D., Peñuelas J., López-Mahía P., Llusià J. (2009) Terpenoid emissions from Quercus robur. A case study of Galicia (NW Spain). Journal of Environmental Monitoring. 11: 1268-1275.LinkDoi: 10.1039/b819960d
Isoprene and monoterpenes emission fluxes emitted by Quercus robur seedlings were measured at a leaf scale in the field. Isoprene emissions were always predominant over the monoterpene ones, α-pinene, β-pinene and camphene being the most abundant emitted monoterpenes. Emission fluxes were normalised at standard conditions of temperature and photosynthetically active radiation, PAR, (30 °C and 1000 mol m-2 s-1 respectively) using temperature and light dependent algorithms. The standardised emission fluxes ranged from 43 to 73 g gDM -1 h -1 for isoprene and from 0.04 to 2.95 g gDM -1 h-1 for the monoterpenes. The values reported in the literature are within our experimental intervals. These standardised fluxes were used to estimate the Quercus robur emissions in Galicia (NW Spain). This region is characterised by its abundant forest extensions where Quercus robur occupies the second place in species abundance with a total of 195029 ha of Quercus robur pure stands. To estimate the region emission fluxes, both the extension and distribution of the forest areas and the regional climatic conditions over five years (2002-2006) were taken into account. The averaged annual fluxes regarding the forest extension were 0.04 t ha-1 yr-1 for isoprene and 0.52 kg ha-1 yr-1 for monoterpenes. This means averaged annual fluxes of 9730 t yr-1 and 114 t yr-1 for isoprene and monoterpenes, respectively. These values place Galicia as an important isoprene emitter power in Spain as a consequence of the extension of its forests more than of the climatic conditions. © 2009 The Royal Society of Chemistry.
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