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21.
Ecological implications of anti-pathogen effects of tropical fungal endophytes and mycorrhizae 总被引:5,自引:0,他引:5
We discuss studies of foliar endophytic fungi (FEF) and arbuscular mycorrhizal fungi (AMF) associated with Theobroma cacao in Panama. Direct, experimentally controlled comparisons of endophyte free (E-) and endophyte containing (E+) plant tissues in T. cacao show that foliar endophytes (FEF) that commonly occur in healthy host leaves enhance host defenses against foliar damage due to the pathogen (Phytophthora palmivora). Similarly, root inoculations with commonly occurring AMF also reduce foliar damage due to the same pathogen. These results suggest that endophytic fungi can play a potentially important mutualistic role by augmenting host defensive responses against pathogens. There are two broad classes of potential mechanisms by which endophytes could contribute to host protection: (1) inducing or increasing the expression of intrinsic host defense mechanisms and (2) providing additional sources of defense, extrinsic to those of the host (e.g., endophyte-based chemical antibiosis). The degree to which either of these mechanisms predominates holds distinct consequences for the evolutionary ecology of host-endophyte-pathogen relationships. More generally, the growing recognition that plants are composed of a mosaic of plant and fungal tissues holds a series of implications for the study of plant defense, physiology, and genetics. 相似文献
22.
Solidago altissima is a dominant perennial of old field succession in North America with the ability to form dense, almost monospecific stands;
the plant is also considered an aggressive invasive throughout Europe and Japan. S. altissima’s success is facilitated by large belowground rhizome systems that allow clonal spread and possible allelopathic suppression
of competitors. A diversity of polar and nonpolar terpenes and polyacetylenes have been described from S. altissima rhizomes; however, there is little information documenting the concentration or distribution of these allelochemicals and
how they relate to plant defense hypotheses. We thus developed a GC–MS method to simultaneously quantify rhizome terpenes
and polyacetylenes that spanned a range of polarities and confirmed the presence of 19 terpenoids in addition to the polyacetylene
dehydromatricaria ester (DME). We, (1) determined relative concentrations and variability of mono-, sesqui-, neutral diterpenes,
diterpene acids and DME within a central NY population; (2) compared accumulation of these compounds in differently developed
rhizome tissue; and (3) tested the alleopathic effect of DME at naturally occurring concentrations on germination and seedling
growth of Asclepias syriaca, a common competitor of S. altissima. Overall, diterpene acids dominated the phytochemical profile of most genotypes (averaging 0.75% of fresh mass) with kolavenic
acid being the single most abundant component. Monoterpene, sesquiterpene and acidic diterpene concentrations were all significantly
greater in the actively elongating (current-year) rhizomes compared to established rhizomes and followed optimal defense theory
predictions. Conversely, DME levels were lower in the current-year rhizomes than in established rhizomes. DME inhibited seed
germination of A. syriaca in a dose-dependent manner. The tissue-specific accumulation of the different compounds may represent a biosynthetic and/or
allocational strategy that limits the exposure of young-tissue to high concentrations of DME possibly limiting the cytotoxic
effects of DME. 相似文献
23.
Joris Koornneef Andrea Ramirez Toon van Harmelen Arjan van Horssen Wim Turkenburg Andre Faaij 《Atmospheric environment (Oxford, England : 1994)》2010,44(11):1369-1385
This study quantifies the trade-offs and synergies between climate and air quality policy objectives for the European power and heat (P&H) sector. An overview is presented of the expected performance data of CO2 capture systems implemented at P&H plants, and the expected emission of key air pollutants, being: SO2, NOX, NH3, volatile organic compounds (VOCs) and particulate matter (PM). The CO2 capture systems investigated include: post-combustion, oxyfuel combustion and pre-combustion capture.For all capture systems it was found that SO2, NOx and PM emissions are expected to be reduced or remain equal per unit of primary energy input compared to power plants without CO2 capture. Increase in primary energy input as a result of the energy penalty for CO2 capture may for some technologies and substances result in a net increase of emissions per kWh output. The emission of ammonia may increase by a factor of up to 45 per unit of primary energy input for post-combustion technologies. No data are available about the emission of VOCs from CO2 capture technologies.A simple model was developed and applied to analyse the impact of CO2 capture in the European P&H sector on the emission level of key air pollutants in 2030. Four scenarios were developed: one without CO2 capture and three with one dominantly implemented CO2 capture system, varying between: post-combustion, oxyfuel combustion and pre-combustion.The results showed a reduction in GHG emissions for the scenarios with CO2 capture compared to the baseline scenario between 12% and 20% in the EU 27 region in 2030. NOx emissions were 15% higher in the P&H sector in a scenario with predominantly post-combustion and lower when oxyfuel combustion (?16%) or pre-combustion (?20%) were implemented on a large scale. Large scale implementation of the post-combustion technology in 2030 may also result in significantly higher, i.e. increase by a factor of 28, NH3 emissions compared to scenarios with other CO2 capture options or without capture. SO2 emissions were very low for all scenarios that include large scale implementation of CO2 capture in 2030, i.e. a reduction varying between 27% and 41%. Particulate Matter emissions were found to be lower in the scenarios with CO2 capture. The scenario with implementation of the oxyfuel technology showed the lowest PM emissions followed by the scenario with a significant share allocated to pre-combustion, respectively ?59% and ?31%. The scenario with post-combustion capture resulted in PM emissions varying between 35% reduction and 26% increase. 相似文献
24.
Andre DuPont 《Mitigation and Adaptation Strategies for Global Change》2013,18(1):97-111
This paper focuses on developing countries that are striving to understand the requirements for the sustainable, commercial development of algae for the production of biofuels. The paper will review the sustainable development of biofuel production, including the major issues that must be addressed before embarking on the path to sustainable biofuel production. The sustainable production of biofuel should be implemented with an ecologically friendly perspective to ensure that future generations will enjoy prosperity of the planet that we share. We can find more than one path for the development of biofuel production from algae but sustainable development must be stressed to ensure prosperity for future generations. 相似文献
25.
26.
Electronic tagging and remotely sensed oceanographic data were used to determine the oceanographic habitat use and preferences
of Atlantic bluefin tuna (Thunnus thynnus L.) exhibiting behaviors associated with breeding in the Gulf of Mexico (GOM). Oceanographic habitats used by 28 Atlantic
bluefin tuna exhibiting breeding behavior (259 days) were compared with available habitats in the GOM, using Monte Carlo tests
and discrete choice models. Habitat utilization and preference patterns for ten environmental parameters were quantified:
bathymetry, bathymetric gradient, SST, SST gradient, surface chlorophyll concentration, surface chlorophyll gradient, sea
surface height anomaly, eddy kinetic energy, surface wind speed, and surface current speed. Atlantic bluefin tuna exhibited
breeding behavior in the western GOM and the frontal zone of the Loop Current. Breeding areas used by the bluefin tuna were
significantly associated with bathymetry, SST, eddy kinetic energy, surface chlorophyll concentration, and surface wind speed,
with SST being the most important parameter. The bluefin tuna exhibited significant preference for areas with continental
slope waters (2,800–3,400 m), moderate SSTs (24–25 and 26–27°C), moderate eddy kinetic energy (251–355 cm2 s−2), low surface chlorophyll concentrations (0.10–0.16 mg m−3), and moderate wind speeds (6–7 and 9–9.5 m s−1). A resource selection function of the bluefin tuna in the GOM was estimated using a discrete choice model and was found
to be highly sensitive to SST. These habitat utilization and preference patterns exhibited by breeding bluefin tuna can be
used to develop habitat models and estimate the probable breeding areas of bluefin tuna in a dynamic environment. 相似文献
27.
28.
Katarzyna A. Michalow Dorota Flak Andre Heel Magdalena Parlinska-Wojtan Mieczyslaw Rekas Thomas Graule 《Environmental science and pollution research international》2012,19(9):3696-3708
TiO2:Nb nanopowders within a dopant concentration in the range of 0.1?C15?at.% were prepared by one-step flame spray synthesis. Effect of niobium doping on structural, optical and photocatalytic properties of titanium dioxide nanopowders was studied. Morphology and structure were investigated by means of Brunauer?CEmmett?CTeller isotherm, X-ray diffraction and transmission electron microscopy. Diffuse reflectance and the resulting band gap energy were determined by diffuse reflectance spectroscopy. Photocatalytic activity of the investigated nanopowders was revised for the photodecomposition of methylene blue (MB), methyl orange (MO) and 4-chlorophenol under UVA and VIS light irradiation. Commercial TiO2-P25 nanopowder was used as a reference. The specific surface area of the powders was ranging from 42.9?m2/g for TiO2:0.1?at.% Nb to 90.0?m2/g for TiO2:15?at.% Nb. TiO2:Nb particles were nanosized, spherically shaped and polycrystalline. Anatase was the predominant phase in all samples. The anatase-related transition was at 3.31?eV and rutile-related one at 3.14?eV. TiO2:Nb nanopowders exhibited additional absorption in the visible range. In comparison to TiO2-P25, improved photocatalytic activity of TiO2:Nb was observed for the degradation of MB and MO under both UVA and VIS irradiation, where low doping level (Nb?<?1?at.%) was the most effective. Niobium doping affected structural, optical and photocatalytic properties of TiO2. Low dopant level enhanced photocatalytic performance under UVA and VIS irradiation. Therefore, TiO2:Nb (Nb?<?1?at.%) can be proposed as an efficient selective solar light photocatalyst. 相似文献
29.
Park K Chow JC Watson JG Trimble DL Doraiswamy P Park K Arnott WP Stroud KR Bowers K Bode R Petzold A Hansen AD 《Journal of the Air & Waste Management Association (1995)》2006,56(4):474-491
Results from six continuous and semicontinuous black carbon (BC) and elemental carbon (EC) measurement methods are compared for ambient samples collected from December 2003 through November 2004 at the Fresno Supersite in California. Instruments included a multi-angle absorption photometer (MAAP; lambda = 670 nm); a dual-wavelength (lambda = 370 and 880 nm) aethalometer; seven-color (lambda = 370, 470, 520, 590, 660, 880, and 950 nm) aethalometers; the Sunset Laboratory carbon aerosol analysis field instrument; a photoacoustic light absorption analyzer (lambda = 1047 nm); and the R&P 5400 ambient carbon particulate monitor. All of these acquired BC or EC measurements over periods of 1 min to 1 hr. Twenty-four-hour integrated filter samples were also acquired and analyzed by the Interagency Monitoring of Protected Visual Environments (IMPROVE) thermal/optical reflectance carbon analysis protocol. Site-specific mass absorption efficiencies estimated by comparing light absorption with IMPROVE EC concentrations were 5.5 m2/g for the MAAP, 10 m2/g for the aethalometer at a wavelength of 880 nm, and 2.3 m2/g for the photoacoustic analyzer; these differed from the default efficiencies of 6.5, 16.6, and 5 m2/g, respectively. Scaling absorption by inverse wavelength did not provide equivalent light absorption coefficients among the instruments for the Fresno aerosol measurements. Ratios of light absorption at 370 nm to those at 880 nm from the aethalometer were nearly twice as high in winter as in summer. This is consistent with wintertime contributions from vehicle exhaust and from residential wood combustion, which is believed to absorb more shorter-wavelength light. To reconcile BC and EC measurements obtained by different methods, a better understanding is needed of the wavelength dependence of light-absorption and mass-absorption efficiencies and how they vary with different aerosol composition. 相似文献
30.
A sensitive and reliable quantification method for Bisphenol A based on modified competitive ELISA method 总被引:1,自引:0,他引:1
Kim A Li CR Jin CF Lee KW Lee SH Shon KJ Park NG Kim DK Kang SW Shim YB Park JS 《Chemosphere》2007,68(7):1204-1209
Bisphenol A (BPA), generally known as bisphenols, has been identified as a potential estrogenic substance. BPA must be conjugated to carrier protein and BSA was commonly used. 4,4-Bis(4-hydroxyphenyl) valeric acid (BHPVA) has a bisphenolic structure and a long carbon chain with a reactive carboxyl group on the end. In this study, BHPVA-BSA was used to produce polyclonal antibody against bisphenolic structure, and a modified competitive ELISA method for quantification of BPA was developed. This system was based on BHPVA-BSA for polyclonal antibody production against bisphenolic structure, and BHPVA-HRP for determination of BPA substituting detection antibody in competitive reaction. Recovery was assessed at 10 different concentrations (2-1000 ng/ml) of BHPVA, and the recovery range was from 96.3% to 107.2%. The variation was from 6.2% to 9.8% for intra assay and from 10.1% to 12.6% for inter assay. The quadratic was used to establish the curve regression. The range was found to be between 2 and 1000 ng/ml. This modified competitive ELISA method has proven to be a very useful tool for quantification of BPA without the unexpected interaction of BSA and anti-BSA polyclonal antibody. 相似文献