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941.
Patricia Delgado Daniel Piñero Virginia Rebolledo Lev Jardón Francisco Chi 《Annals of Forest Science》2011,68(1):121-128
• Introduction
The recognition of endangered species takes into account geographic isolation and small size of populations, as is the case of two populations of Pinus caribaea var. hondurensis distributed in México. 相似文献942.
Ernesto Escalante Valentín Pando Cristóbal Ordoñez Felipe Bravo 《Annals of Forest Science》2011,68(4):715-726
• Introduction
Understanding diameter growth of the Mediterranean pine species is fundamental for evaluating and making appropriate strategic decisions in forest management. A matrix diameter growth model for two Mediterranean pine forest ecosystems in Spain has been developed. 相似文献943.
Encarna Rodríguez-García Cristóbal Ordóñez Felipe Bravo 《Annals of Forest Science》2011,68(2):337-346
• Introduction
Shrubs are recognized as important tree regeneration niches. In this study, we experimentally analysed the effects of shrub presence, canopy cover (closed cover and open cover-gaps), and seedling size on Pinus pinaster growth. 相似文献944.
• Context
Landscape structure is crucial for forest conservation in regions where the natural forest is fragmented. Practical conservation is currently shifting from local stands to a landscape perspective, although few studies have tested the relative effects of different spatial scales on plant species composition and diversity in forests. 相似文献945.
Corella-Madueño MA Harris MK Fu-Castillo AA Martínez-Téllez MA Valenzuela-Soto EM Gálvez-Ruiz JC Vargas-Arispuro I 《Pest management science》2011,67(12):1522-1527
BACKGROUND: Plant volatiles have complex intra‐ and interspecific effects in the environment that include plant/herbivore interactions. Identifying the quantity and quality of volatiles produced by a plant is needed to aid the process of determining which chemicals are exerting what effects and then examining whether these effects can be manipulated to benefit society. The qualitative characterization of volatile compounds emitted by pecan, Carya illinoinensis (Wang.) K. Koch, was begun in order to establish a database for investigating how these volatiles affect Acrobasis nuxvorella Nuenzig, a monophagous pest of pecan. Headspace solid‐phase microextraction combined with gas chromatography–mass spectrometry was used for the analysis of the volatile constituents of pecan during three phenological stages (dormant buds, intact new shoot growth and intact nutlets) of the Western Schley and Wichita cultivars. RESULTS: About 111 distinct compounds were identified from the two cultivars, accounting for ~99% of the headspace volatiles. The chromatographic profiles of both varieties revealed variations in the volatile composition and proportion between cultivars, with a predominance of terpene hydrocarbons, of the sesquiterpenes class, as well as monoterpenes. CONCLUSION: The significantly higher responsiveness recorded for the larvae of A. nuxvorella to C. illinoinensis shoots indicates that the larvae may be activated by terpenes emanating from the new shoot growth. This is the first study that has examined volatiles of pecan in Mexico. Copyright © 2011 Society of Chemical Industry 相似文献
946.
Hortensia Sixto Jordi Salvia Marcos Barrio Mª Pilar Ciria Isabel Cañellas 《New Forests》2011,42(2):163-177
Growth and production in the first year, as additional selection criteria, were assessed for nine poplar clones to be used
as short rotation woody crops (SRWC) in the production of biomass for energy purposes. In order to identify the most promising
clones in terms of growth and yield and also to assess their stability, trials were established at different locations in
Spain. The majority of these clones, which form part of the European list of base materials, have frequently been used in
plantations aimed at timber production but not for biomass in Mediterranean conditions. Others, such as those selected in
Italy specifically for biomass production (currently provisionally admitted), are being tested for the first time under different
soil and climatic conditions in Southwest Europe. The early selection of clones for rapid juvenile growth provides a valuable
additional input to the clonal selection process, especially where very short rotations are desired (no more than 3 years).
In any case, determining clonal stability in terms of growth is of great use not only when deciding on the clones to be used
in plantations but also when developing breeding programs. ANOVA and Genotype plus Genotype × Environment (GGE) biplot analyses
were used to analyse the growth and stability of the clones, which were then ranked according to mean performance and stability.
Differences were detected between clones as well as between the different environments tested. The biplot analysis allowed
different groups of clones to be identified according to their performance and degree of interaction displayed, thus providing
useful information for the selection process. The production of aboveground biomass in the first vegetative period ranged
from 1.7 to 8.0 Mg DM ha−1 at the different sites. ‘Monviso’, ‘Guardi’, ‘AF2’ and ‘2000 verde’ were the most productive clones whereas ‘Unal’, ‘Pegaso’
and ‘USA 49-177’ were the least productive. The stability analysis identified ‘AF2’, ‘Guardi’, ‘I-214’ and ‘MC’ as more stable
clones while ‘Monviso’, ‘2000 verde’, ‘Unal’, ‘Pegaso’ and ‘USA 49-177’ were found to be specifically adapted to certain environments.
This implies that where information on site conditions is not available, the ‘AF2’ and ‘Guardi’ clones offer greater assurance
of successful establishment and higher initial growth. The growth of ‘Monviso’ ‘2000 verde’ ‘Unal’ ‘Pegaso’ and ‘USA 49-177’
clones is highly dependent on site conditions during the establishment phase. Similarly, the SH (Shore Henares river) and
LT (La Tallada) sites were identified as the most highly discriminative environments for the set of clones while CS (Cubo
de la Solana) and AR (Atarfe) were identified as those where performance levels were average. 相似文献
947.
Bernardino-Nicanor A Añón MC Scilingo AA Dávila-Ortíz G 《Journal of agricultural and food chemistry》2005,53(9):3613-3617
Five guava seed glutelin extracts were obtained with different buffer solutions: Na(2)B(4)O(7) alone (Glut.Bo) or containing SDS (Glut.BoSDS), 2-mercaptoethanol (Glut.Bo2-ME), or a combination of both (Glut.BoSDS2-ME) and NaOH (Glut.Na). All borate buffer solutions were at pH 10. The higher yield of glutelins corresponded to the Glut.BoSDS extract (81.9% dry basis) and the lower to Glut.Bo (6.8%). The functional properties of the five guava seed glutelin extracts were determined. Glut.BoSDS, Glut.BoSDS2-ME, and Glut.Na showed high values for several properties, including surface hydrophobicity (7.7, 10.8, and 0.6, respectively), solubility at pH 10 (91.1, 77.9, and 96.7, respectively), water-holding capacity at pH 3.6 (1.7, 2.5, and 2.8, respectively), emulsifying activity index (pH 10; 503.5, 238.2, and 838.0, respectively), and foaming properties (pH 10; V(0) = 0.14, 0.25, and 0.19, respectively; V(max) = 6.1, 5.59, and 4.51, respectively; t(1/2) = 266, 255.3, and 94 s, respectively). These results suggest that the denaturing reagent (SDS or NaOH) during extraction conferred on the proteins a structure that facilitated the development of their functional properties. 相似文献
948.
Athès V Peña y Lillo M Bernard C Pérez-Correa R Souchon I 《Journal of agricultural and food chemistry》2004,52(7):2021-2027
Several experimental methodologies exist for measuring volatilities; however, results show great dispersion and sometimes lack of agreement between different methods. The aim of our study was to compare the performance of three static headspace methods (vapor phase calibration, VPC; phase ratio variation, PRV; and liquid calibration static headspace, LC-SH) for determining gas/liquid partition coefficients of two aroma compounds in hydroalcoholic multicomponent solutions at infinite dilution. Comparison with literature data based on static and dynamic methods showed that PRV is simpler than VPC and LC-SH and that VPC and PRV are more accurate than LC-SH, which presented a significant bias (50% lower values). 相似文献
949.
Yagüe C Bayarri S Conchello P Lázaro R Pérez-Arquillué C Herrera A Ariño A 《Journal of agricultural and food chemistry》2005,53(13):5105-5109
A multicolumn solid-phase extraction cleanup for the determination of organophosphorus (OP) and organochlorine (OC) pesticides plus PCB congeners in virgin olive oil is presented. The method involves dissolution of the olive oil in hexane, followed by a cleanup system using a diatomaceous earth column (Extrelut-QE) with reversed (C(18)) and normal (alumina) phase SPE columns. Determination of OPs was by GC-NPD, while the OCs and PCBs were analyzed using GC-ECD. Recovery assays for OPs varied from 81.7% to 105.3%, for OCs ranged between 74.3% and 99.4%, while for PCBs were from 60.1% to 119.2%. Quantitation limits ranged from 10 to 25 microg/kg olive oil for OPs, and from 1 to 6 microg/kg olive oil for OCs and PCBs. In the case of positive samples, the confirmation of pesticide identity was performed by ion-trap GC-MS/MS. The applicability of the method was assayed with 19 virgin olive oil samples collected from different olive mills of Aragón (Spain). Only one OP pesticide (acephate) was detected in one sample at a concentration of 10 microg/kg. Organochlorine pesticides were found in 5-47% of samples at very low levels ranging from 1.5 to 5.2 microg/kg. PCBs were found in 20-90% of samples, showing concentrations between 2.3 and 17.3 microg/kg. 相似文献
950.
F. Rodá J. Bellot A. Avila A. Escarré J. Piñol J. Terradas 《Water, air, and soil pollution》1993,66(3-4):277-288
Saharan dust delivered by so-called ‘red rains’ strongly influences precipitation chemistry in the Mediterranean region. We show here that at rural sites in eastern Spain, red rains have much higher ion concentrations than non-red rains, and they account for up to 50% of the mean annual input of dissolved elements in bulk precipitation, though they make up only a minor part of the annual rainfall. The mean annual input of alkalinity in red rains is enough to neutralize the input of free acidity in acidic precipitation. Transport of Saharan dust is thus a major ecological force in Mediterranean ecosystems through its effects on the acid neutralizing capacity of the atmosphere and the atmospheric deposition of elements. 相似文献