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Though it is known that flower scent not only attracts pollinators but also herbivores, little is known about the importance
of flower scent on the distribution of leaf herbivores among individuals within a plant species. In this study we determined
the distribution of galls induced by the sawfly Pontania proxima (Serville 1823) (Hymenoptera, Tenthredinidae, Nematinae) on flowering and non-flowering representatives of several clones
belonging to Salix fragilis and S. × rubens (Salicaceae). Further, amounts and composition of scent of flowering and non-flowering twigs were compared (dynamic headspace-gas
chromatography–mass spectrometry, DHS-GC–MS), and a scent sample collected from flowering twigs of S. fragilis was tested by coupled gas chromatography and electroantennographic detection (GC-EAD) on the antennae of P. proxima females. The results show that the presence of flower catkins on plants led to a higher degree of allocation with galls,
but the number of galls differed not between flowering and non-flowering plants. The DHS-GC–MS analyses revealed that the
total amount of flower scent emitted per flowering twig is about 90 times higher than the scent emitted by a non-flowering
twig. Further, several compounds were emitted only by flowering but not by non-flowering twigs. In the GC-EAD analyses, antennae
consistently responded not only to green leaf volatiles, but also to compounds emitted only by the flowers (e.g. 1,4-dimethoxybenzene).
These flower scent compounds are suggested to affect the host plant choice by attracting more sawflies from the distance to
flowering plants compared to non-flowering plants. The EAD-active compounds emitted from vegetative plant parts are assumed
to act as long-distance signals especially when flowers are absent on host plants, e.g. during the oviposition period of the
second generation of P. proxima. 相似文献
204.
Zhou Nicolette A. Fagnant-Sperati Christine S. Komen Evans Mwangi Benlick Mukubi Johnstone Nyangao James Hassan Joanne Chepkurui Agnes Maina Caroline van Zyl Walda B. Matsapola Peter N. Wolfaardt Marianne Ngwana Fhatuwani B. Jeffries-Miles Stacey Coulliette-Salmond Angela Peñaranda Silvia Shirai Jeffry H. Kossik Alexandra L. Beck Nicola K. Wilmouth Robyn Boyle David S. Burns Cara C. Taylor Maureen B. Borus Peter Meschke John Scott 《Food and environmental virology》2020,12(1):35-47
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206.
Thorsten Zellmann Alexandra S. B?uerle Reiner Doluschitz Dietmar Jahnke und Detlef Marell 《Umweltwissenschaften und Schadstoff-Forschung》1999,11(3):181-186
Zusammenfassung Die Erfassung der Ist-Situation im Rahmen der Umweltprüfung bildet die Grundlage für effiziente Schritte im Rahmen der Implementierung
von Umweltmanagementsystemen (UMS). Diese Basis-analyse stützt sich auf die Elemente Wirkungsaudit, Management-audit und Rechtsaudit.
Durch die optimale Ausgestaltung einer Umweltprüfung wird bei der Implementierung eines UMS auch in der Landwirtschaft die
Basis für einen maximalen Nutzen des Anwenders geschaffen. Dieser Nutzen ist etwa für den Betrieb in seinen Innenbeziehungen,
die Transparenz der Betriebsabl?ufe, ?konomische Gesichtspunkte, wie z.B. Einsparpotentiale, Informationsgewinnung sowie Effizienzgesichtspunkte
durch die Dokumentation der Ablauforganisation. Darüber hinaus nutzt ein UMS bei externen Anforderungen, wie z.B. beim Umgang
mit der ?ffentlichkeit, Marktpartnern, der Stellung gegenüber Beh?rden, Deregulierung oder Haftungsminimierung.
相似文献
207.
Bruno Pennelli Karl-Otto Nagel Giuseppe Crivellaro Claudio Fabiani Alexandra Vancova Laura Mancini 《Water environment research》2006,78(4):446-455
The European Union Water Framework Directive requires the achievement of environmental objectives for the ecological quality of water bodies. A comparable implementation of the Directive throughout member countries of the European Union is necessary to verify equal protection of surface waters. The Directive specifies that member states determine ecological quality by means of biological indices. To improve comparability of water quality assessment, this research carried out an intercalibration trial between the Slovak Saprobic Index and the Italian protocol of the Extended Biotic Index, as part of a cooperative program between Italy and the Slovak Republic. When assessing streams with no or low pollution, statistics showed similar results for both methods. In contrast, the comparison of indices was not accurate in the case of severely affected waters. Reliable conversion formulas are feasible to transform the Italian Extended Biotic Index into the Slovak Saprobic Index, and not vice versa. 相似文献
208.
Breffní Lennon Niall Dunphy Christine Gaffney Alexandra Revez Gerard Mullally Paul O’Connor 《Journal of Environmental Policy & Planning》2020,22(2):184-197
ABSTRACTThe transition to more sustainable energy systems has set about redefining the social roles and responsibilities of citizens. Implicit in this are expectations around participation, though the precise contours of what this might mean remain open. Debates around the energy transition have been skewed towards a normative construct of what it means to be a ‘good citizen’, the parameters for which are shaped by predetermined visions of statist and/or market-driven determinations of the energy systems of the future. This article argues that concepts such as ‘energy citizen’ are co-opted to reflect popular neoliberal discourses, and ignore crucial questions of unequal agency and access to resources. Paradoxically, official discourses that push responsibility for the energy transition onto the ‘citizen-as-consumer’ effectively remove agency from citizens, leaving them largely disconnected and disempowered. Consequently, energy citizenship needs to be reconceptualised to incorporate more collective and inclusive contexts for action. Considering how much energy consumption occurs in (traditionally female) domestic spheres, do conventional notions of citizenship (especially with regards to its associated rights and duties) need to be recalibrated in order for the concept to be usefully applied to the energy transition? 相似文献
209.
Fire disturbance is a primary agent of change in the mediterranean-climate chaparral shrublands of southern California, USA. However, fire frequency has been steadily increasing in coastal regions due to ignitions at the growing wildland-urban interface. Although chaparral is resilient to a range of fire frequencies, successively short intervals between fires can threaten the persistence of some species, and the effects may differ according to plant functional type. California shrublands support high levels of biological diversity, including many endangered and endemic species. Therefore, it is important to understand the long-term effects of altered fire regimes on these communities. A spatially explicit simulation model of landscape disturbance and succession (LANDIS) was used to predict the effects of frequent fire on the distribution of dominant plant functional types in a study area administered by the National Park Service. Shrubs dependent on fire-cued seed germination were most sensitive to frequent fire and lost substantial cover to other functional types, including drought-deciduous subshrubs that typify coastal sage scrub and nonnative annual grasses. Shrubs that resprout were favored by higher fire frequencies and gained in extent under these treatments. Due to this potential for vegetation change, caution is advised against the widespread use of prescribed fire in the region. 相似文献
210.