Search results for "Systematic"
showing 10 items of 7608 documents
Metabolism of chlortoluron in tolerant species: possible role of cytochrome p-450 mono-oxygenases
1988
Summary Pathways of chlortoluron metabolism were compared in excised leaves of four tolerant species, namely wheat (Triticum aestivum var Clement), Bromus sterilis, Galium aparine and Veronica persica. The herbicide was principally detoxified by hydroxylation of the ring methyl in wheat and by N-dealkylation in Veronica persica. Both pathways were involved in Bromus sterilis and Galium aparine. Kinetic study of the degradation showed that capacity to form non-toxic conjugates could, at least partially, explain the tolerance of these species to chlortoluron. In plants treated with 1-aminobenzotriazole, a cytochrome P-450 enzyme inactivator, N-dealkylation of chlortoluron was little or not af…
Life‐form diversity across temperate deciduous forests of Western Eurasia: A different story in the understory
2021
[Aim]To analyse the biogeographic patterns of Temperate Deciduous Forests (TDFs) in Western Eurasia based on different life-forms and forests layers and explore their relationships with the current climate, Last Glacial Maximum (LGM) climate and topography.
Seed oils as additives: penetration of triolein, methyloleate and diclofop-methyl in maize leaves
1992
Summary: Resume: Zusammenfassung Methyl ester derivatives of seed oils have a greater effect on graminicide efficacy than the parent oils. To explain this difference, we investigated the penetration of the radiolabelled oils, triolein (TRI) and methyl oleate (MEO), in maize leaves, and their influence on diclofop-methyl penetration. Over a period of 3 h 30% of applied TRI penetrated maize leaves, but no further penetration was observed. In contrast, MEO entry proceeded regularly to 72% over a period of 27 h. The amount of oil found in epicuticular wax (chloroform wash) was generally less than 4% of the recovered label, and was even lower (<1%) in ‘glossy 1’ hybrids which have no crystalline…
Isolation and identification of 4,6,8-trimethyl-7,9-undecadien-5-ol, a female-specific compound, in tergal gland secretion ofCryptocercus punctulatus…
1991
International audience; The secretion of the tergal glands of Cryptocercus punctulatus consists of a complex mixture of 27 compounds. Of this mixture, only one compound (compound B) is specific for females. By dissecting 200 tergal glands, 50 µg of pure compound B was collected by preparative GC; it was identified as (Z, E-4,6,8-trimethyl-7,9-undecadien-5-oI. Its functions as well as its absolute configuration still have to be determined.
Can the large ecological amplitude of Ambrosia artemisiifolia explain its invasive success in France?
2008
International audience; In order to understand the successful spread of Ambrosia artemisiifolia in France, the variability of colonised habitat by this species was studied at 48 locations, from its central to peripheral area of distribution. Each site was characterised by a vegetation survey, a description of the A. artemisiifolia population and a soil analysis. Differences in the number of species, Shannon diversity index, evenness index and plant life form spectra were compared among the sites. A total of 276 species occurring along with A. artemisiifolia was observed. Therophytes and hemicryptophytes represented more than 80% of all the species. The two most frequent species occurring al…
Degradation of sexual reproduction in Veronica filiformis after introduction to Europe
2011
Abstract Background Baker’s law predicts that self-incompatible plant species are generally poor colonizers because their mating system requires a high diversity of genetically differentiated individuals and thus self-compatibility should develop after long-distance dispersal. However, cases like the introduction of the self-incompatible Veronica filiformis (Plantaginaceae) to Europe constitute an often overlooked alternative to this rule. This species was introduced from subalpine areas of the Pontic-Caucasian Mountains and colonized many parts of Central and Western Europe in the last century, apparently without producing seeds. To investigate the consequences of the absence of sexual rep…
From clear lakes to murky waters – tracing the functional response of high-latitude lake communities to concurrent ‘greening’ and ‘browning’
2019
Climate change and the intensification of land use practices are causing widespread eutrophication of subarctic lakes. The implications of this rapid change for lake ecosystem function remain poorly understood. To assess how freshwater communities respond to such profound changes in their habitat and resource availability, we conducted a space-for-time analysis of food-web structure in 30 lakes situated across a temperature-productivity gradient equivalent to the predicted future climate of subarctic Europe (temperature +3 degrees C, precipitation +30% and nutrient +45 mu g L-1 total phosphorus). Along this gradient, we observed an increase in the assimilation of pelagic-derived carbon from…
Protist predation can select for bacteria with lowered susceptibility to infection by lytic phages
2015
Background: Consumer-resource interactions constitute one of the most common types of interspecific antagonistic interaction. In natural communities, complex species interactions are likely to affect the outcomes of reciprocal co-evolution between consumers and their resource species. Individuals face multiple enemies simultaneously, and consequently they need to adapt to several different types of enemy pressures. In this study, we assessed how protist predation affects the susceptibility of bacterial populations to infection by viral parasites, and whether there is an associated cost of defence on the competitive ability of the bacteria. As a study system we used Serratia marcescens and i…
Individual-Based Tracking Systems in Ornithology: Welcome to the Era of Big Data
2016
Technological innovations have led to exciting fast-moving developments in science. Today, we are living in a technology-driven era of biological discovery. Consequently, tracking technologies have facilitated dramatic advances in the fundamental understanding of ecology and animal behaviour. Major technological improvements, such as the development of GPS dataloggers, geolocators and other bio-logging technologies, provide a volume of data that were hitherto unconceivable. Hence we can claim that ornithology has entered the era of big data. In this paper, which is particularly addressed to undergraduate students and starting researchers in the emerging field of movement ecology, I summaris…
Diurnal timing of nonmigratory movement by birds: the importance of foraging spatial scales
2020
Timing of activity can reveal an organism's efforts to optimize foraging either by minimizing energy loss through passive movement or by maximizing energetic gain through foraging. Here, we assess whether signals of either of these strategies are detectable in the timing of activity of daily, local movements by birds. We compare the similarities of timing of movement activity among species using six temporal variables: start of activity relative to sunrise, end of activity relative to sunset, relative speed at midday, number of movement bouts, bout duration and proportion of active daytime hours. We test for the influence of flight mode and foraging habitat on the timing of movement activit…