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S. Marañón-Jiménez J. Castro A.S. Kowalski P. Serrano-OrtizB.R. Reverter E.P. Sánchez-Cañete R. Zamora 《Forest Ecology and Management》2011,261(8):1436-1447
After a wildfire, the management of burnt wood may determine microclimatic conditions and microbiological activity with the potential to affect soil respiration. To experimentally analyze the effect on soil respiration, we manipulated a recently burned pine forest in a Mediterranean mountain (Sierra Nevada National and Natural Park, SE Spain). Three representative treatments of post-fire burnt wood management were established at two elevations: (1) “salvage logging” (SL), where all trees were cut, trunks removed, and branches chipped; (2) “non-intervention” (NI), leaving all burnt trees standing; and (3) “cut plus lopping” (CL), a treatment where burnt trees were felled, with the main branches lopped off, but left in situ partially covering the ground surface. Seasonal measurements were carried out over the course of two years. In addition, we performed continuous diurnal campaigns and an irrigation experiment to ascertain the roles of soil temperature and moisture in determining CO2 fluxes across treatments. Soil CO2 fluxes were highest in CL (average of 3.34 ± 0.19 μmol m−2 s−1) and the lowest in SL (2.21 ± 0.11 μmol m−2 s−1). Across seasons, basal values were registered during summer (average of 1.46 ± 0.04 μmol m−2 s−1), but increased during the humid seasons (up to 10.07 ± 1.08 μmol m−2 s−1 in spring in CL). Seasonal and treatment patterns were consistent at the two elevations (1477 and 2317 m a.s.l.), although respiration was half as high at the higher altitude.Respiration was mainly controlled by soil moisture. Watering during the summer drought boosted CO2 effluxes (up to 37 ± 6 μmol m−2 s−1 just after water addition), which then decreased to basal values as the soil dried. About 64% of CO2 emissions during the first 24 h could be attributed to the degasification of soil pores, with the rest likely related to biological processes. The patterns of CO2 effluxes under experimental watering were similar to the seasonal tendencies, with the highest pulse in CL. Temperature, however, had a weak effect on soil respiration, with Q10 values of ca. 1 across seasons and soil moisture conditions. These results represent a first step towards illustrating the effects of post-fire burnt wood management on soil respiration, and eventually carbon sequestration. 相似文献
43.
Natera R Castro R de Valme García-Moreno M Hernández MJ García-Barroso C 《Journal of agricultural and food chemistry》2003,51(11):3345-3351
The phenolic composition, aroma compounds, and organic acid content of 83 vinegars have been determined. Multivariate analysis techniques have been used to classify these vinegar samples according to raw material (white wine, red wine, apple, honey, alcohol, balsamic, and malt) and production process (with and without aging in wood). Cluster analysis grouped the samples according to production process. Only apple and balsamic vinegars were separated from wine vinegars. Alcohol, honey, and malt vinegars were grouped with no aged wine vinegars. Linear discriminate analysis allowed a 88% differentiation according to raw material and 100% according to aging in wood. Besides, from the results obtained, a major role of the volatile compounds in the differentiation of the vinegar samples according to their aging period in wood can be seen. 相似文献
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Campbell John L. Hornbeck James W. Mitchell Myron J. Adams Mary Beth Castro Mark S. Driscoll Charles T. Kahl Jeffrey S. Kochenderfer James N. Likens Gene E. Lynch James A. Murdoch Peter S. Nelson Sarah J. Shanley James B. 《Water, air, and soil pollution》2004,151(1-4):373-396
Input-output budgets for dissolved inorganic nitrogen (DIN) are summarized for 24 small watersheds at 15 locations in the northeasternUnited States. The study watersheds are completely forested, free of recent physical disturbances, and span a geographical region bounded by West Virginia on the south and west, and Maine on the north and east. Total N budgets are not presented; however, fluxes of inorganic N in precipitation and streamwater dominate inputs and outputs of N at these watersheds. The range in inputs of DIN in wet-only precipitation from nearby National Atmospheric Deposition Program (NADP) sites was 2.7 to 8.1 kg N ha-1 yr-1 (mean = 6.4 kg N ha-1 yr-1; median = 7.0 kg N ha-1 yr-1). Outputs of DIN in streamwater ranged from 0.1 to 5.7 kg N ha-1 yr-1 (mean = 2.0 kg N ha-1 yr-1; median = 1.7 kg N ha-1 yr-1). Precipitation inputs of DIN exceeded outputs in streamwater at all watersheds, with net retention of DIN ranging from 1.2 to 7.3 kg N ha-1 yr-1 (mean = 4.4 kg N ha-1 yr-1; median = 4.6 kg N ha-1 yr-1). Outputs of DIN in streamwater were predominantly NO3-N (mean = 89%; median = 94%). Wet deposition of DIN was not significantly related to DIN outputs in streamwater for these watersheds. Watershed characteristics such as hydrology, vegetation type, and land-use history affect DIN losses and may mask any relationship between inputs and outputs. Consequently, these factors need to be included in the development of indices and simulation models for predicting 'nitrogen saturation' and other ecological processes. 相似文献
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Thirty-nine grapevine cultivars widely grown in Portugal, especially in Vinhos Verdes and Douro regions, and two well known international cultivars as standards, were genotyped at 12 microsatellite loci. The number of alleles per locus ranged from 6 to 12, and the number of allelic combinations per locus from 13 to 26. The total number of unique genotypes in the 12 analysed loci was 120, having most of the cultivars (38 out of 41) at least one unique genotype in any of the loci. The microsatellite profiles were adequate to discriminate 41 cultivars. The level of observed heterozygosity at each locus varied from 70.7% to 95.1%. VVMD28 has been revealed as one of the most informative markers. Several synonymies between Spanish and Portuguese cultivars were confirmed, and some homonymies are discussed. The genetic profiles of all 41 cultivars were searched for possible parent-offspring groups. The data obtained revealed the possible descendence of Touriga Franca from Touriga Nacional and Marufo. 相似文献
49.
Castro SM Van Loey A Saraiva JA Smout C Hendrickx M 《Journal of agricultural and food chemistry》2004,52(18):5724-5729
Pectin methylesterase (PME) from green bell peppers (Capsicum annuum) was extracted and purified by affinity chromatography on a CNBr-Sepharose-PMEI column. A single protein peak with pectin methylesterase activity was observed. For the pepper PME, a biochemical characterization in terms of molar mass (MM), isoelectric points (pI), and kinetic parameters for activity and thermostability was performed. The optimum pH for PME activity at 22 degrees C was 7.5, and its optimum temperature at neutral pH was between 52.5 and 55.0 degrees C. The purified pepper PME required the presence of 0.13 M NaCl for optimum activity. Isothermal inactivation of purified pepper PME in 20 mM Tris buffer (pH 7.5) could be described by a fractional conversion model for lower temperatures (55-57 degrees C) and a biphasic model for higher temperatures (58-70 degrees C). The enzyme showed a stable behavior toward high-pressure/temperature treatments. 相似文献
50.
The wide distribution of Scots pine (Pinus sylvestris L.) in Europe includes two relict populations in southern Spain (Sierra Nevada and Sierra de Baza), belonging to the subspecies nevadensis. These populations are isolated in high mountains, which tends to protect them from the attack of a severe defoliating Mediterranean pest, the pine processionary moth Thaumetopoea pityocampa. However, as a consequence of climate change, the pine processionary caterpillar has increasingly attacked populations of this pine in recent years. This work describes the detrimental effects of defoliation by the pine processionary caterpillar in P. sylvestris subsp. nevadensis in Sierra Nevada. Defoliation strongly reduced pine growth as well as all the reproductive parameters measured (female and male cone production, mature cone size, seed production and seed weight), in addition to some deaths. If winter temperatures continue to increase, the pine processionary caterpillar will have a dangerous impact in these relict pine populations, by further reducing the pine's weak regeneration capacity. We suggest some mitigation actions based on managing habitat structure, in order to reduce or avoid such negative impacts. 相似文献