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PDGFB as a vascular normalization agent in an ovarian cancer model treated with a gamma‐secretase inhibitor 下载免费PDF全文
994.
Plant diversity induces shifts in the functional structure and diversity across trophic levels 下载免费PDF全文
Anne Ebeling Michael Rzanny Markus Lange Nico Eisenhauer Lionel R. Hertzog Sebastian T. Meyer Wolfgang W. Weisser 《Oikos》2018,127(2):208-219
Changes to primary producer diversity can cascade up to consumers and affect ecosystem processes. Although the effect of producer diversity on higher trophic groups have been studied, these studies often quantify taxonomy‐based measures of biodiversity, like species richness, which do not necessarily reflect the functioning of these communities. In this study, we assess how plant species richness affects the functional composition and diversity of higher trophic levels and discuss how this might affect ecosystem processes, such as herbivory, predation and decomposition. Based on six different consumer traits, we examined the functional composition of arthropod communities sampled in experimental plots that differed in plant species richness. The two components we focused on were functional variation in the consumer community structure (functional structure) and functional diversity, expressed as functional richness, evenness and divergence. We found a consistent positive effect of plant species richness on the functional richness of herbivores, carnivores, and omnivores, but not decomposers, and contrasting patterns for functional evenness and divergence. Increasing plant species richness shifted the omnivore community to more predatory and less mobile species, and the herbivore community to more specialized and smaller species. This was accompanied by a shift towards more species occurring in the vegetation than in the ground layer. Our study shows that plant species richness strongly affects the functional structure and diversity of aboveground arthropod communities. The observed shifts in body size (herbivores), specialization (herbivores), and feeding mode (omnivores) together with changes in the functional diversity may underlie previously observed increases in herbivory and predation in plant communities of higher diversity. 相似文献
995.
Bijeesh Kozhikkodan Veettil Sebastian Felipe Ruiz Pereira Ngo Xuan Quang 《Hydrobiologia》2018,814(1):19-30
IPCC predictions indicate an increase in temperatures by 1.5–7°C in some Amazonian regions during the twenty-first century. These changes could disrupt the present distribution patterns of organisms, including wetland plant species. In this work, we determined in microcosms the effects of scenarios combining elevated temperature and atmospheric CO2 concentration on the germination and initial growth of the arborescent Amazonian aquatic macrophyte Montrichardia arborescens. Seeds were germinated, and seedlings produced were monitored over a 5-month period in four microcosms: Control: ambient temperature and CO2 level; Mild: Control + 1.5°C and + 200 ppm CO2; intermediate: control + 2.5°C and + 400 ppm CO2; Extreme: Control + 4.5°C and + 850 ppm of CO2. Rapid light response curves and Fv/Fm values taken in seedlings showed a decrease in electron transportation rate with CO2 and temperature elevation. Mild and Intermediate treatments stimulated biomass production; Extreme treatment and Control produced similar results. The severe climatic changes expected in the future may negatively influence carbon accumulation in M. arborescens. Since aquatic macrophytes in Amazonian wetlands and wetlands worldwide are key plant species, further studies are needed to predict their fate in a global change perspective. 相似文献
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Feng Lu Sundberg Sebastian Ooi Mark K. J. Wu Yu-Huan Wang Meng Bu Zhao-Jun 《Plant and Soil》2018,432(1-2):403-413
Plant and Soil - To test the effects of characteristic ecological gradients in peatlands including oxygen-deficiency and allelopathy on Sphagnum spore persistence. We determined the initial... 相似文献
998.
Koebernick Nicolai Schlüter Steffen Blaser Sebastian R. G. A. Vetterlein Doris 《Plant and Soil》2018,431(1-2):417-431
Plant and Soil - Root shrinkage in drying soil has been shown repeatedly. The aim of this study was to investigate the dynamics of root-soil contact and its relationship with plant water status... 相似文献
999.
Dimeric cytochromes bc are central components of photosynthetic and respiratory electron transport chains. In their catalytic core, four hemes b connect four quinone (Q) binding sites. Two of these sites, Qi sites, reduce quinone to quinol (QH2) in a step-wise reaction, involving a stable semiquinone intermediate (SQi). However, the interaction of the SQi with the adjacent hemes remains largely unexplored. Here, by revealing the existence of two populations of SQi differing in paramagnetic relaxation, we present a new mechanistic insight into this interaction. Benefiting from a clear separation of these SQi species in mutants with a changed redox midpoint potential of hemes b, we identified that the fast-relaxing SQi (SQiF) corresponds to the form magnetically coupled with the oxidized heme bH (the heme b adjacent to the Qi site), while the slow-relaxing SQi (SQiS) reflects the form present alongside the reduced (and diamagnetic) heme bH. This so far unreported SQiF calls for a reinvestigation of the thermodynamic properties of SQi and the Qi site. The existence of SQiF in the native enzyme reveals a possibility of an extended electron equilibration within the dimer, involving all four hemes b and both Qi sites. This substantiates the predicted earlier electron transfer acting to sweep the b-chain of reduced hemes b to diminish generation of reactive oxygen species by cytochrome bc1. In analogy to the Qi site, we anticipate that the quinone binding sites in other enzymes may contain yet undetected semiquinones which interact magnetically with oxidized hemes upon progress of catalytic reactions. 相似文献
1000.
The aim of the present research was to investigate the influence of packaging design on consumers' perception of quality of fresh carrots. We adopted a conjoint analytic approach in which 251 Danish consumers rated the perceived quality and value (expected price) of nine packaging images, obtained by systematically varying packaging type (plastic bag, plastic box, cardboard paper) and label color (blue, brown, grey). The results revealed that the main attribute influencing the perceptions of the consumer was packaging type. Specifically, the box packages (both plastic and cardboard) were associated to carrots of significantly higher perceived value and quality compared to the plastic bag packages. Furthermore, the study identified the most important aspects consumers attend to when purchasing carrots. A transparent packaging, allowing consumers to inspect the produce, was mentioned as the most important aspect. Being organic and local were identified as the second and third most important, respectively.