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Pyrrolizidine alkaloids in Senecio vulgaris L. depending on development stage and season
Get PDFDas Gewöhnliche Greiskraut (Senecio vulgaris L.) wird aufgrund seiner toxischen Inhaltsstoffe (Pyrrolizidinalkaloide, PAs) und seines enormen Verbreitungspotentials in landwirtschaftlichen Sonderkulturen als problematisch eingestuft (Robinson et al., 2003; BfR, 2007; Wiedenfeld, 2011; Wiedenfeld und Edgar, 2011). Die vorliegende Untersuchung hatte daher zum Ziel in Parzellenfreilandversuchen die Wachstumsparameter von Senecio vulgaris und den Gehalt von verschiedenen PAs hinsichtlich ontogenetischer Unterschiede zu verschiedenen Jahreszeiten zu untersuchen.Wie bereits für andere Senecio-Arten gezeigt, wird auch in Senecio vulgaris der PA-Gehalt (PA-Gesamtsumme, tertiäre PAs und PA-N-oxide) je nach Jahreszeit durch das Entwicklungsstadium beeinflusst. Allgemein zeigt sich eine Tendenz, dass die PA-Konzentration bis zur Vollblüte ansteigt und nachfolgend zur Frucht- und Samenreife wieder abnimmt. Von den N-oxiden wurden jeweils höhere Gehalte als von den entsprechenden tertiären PAs gefunden. Die Einzelverbindungen werden in ihrer Konzentration unterschiedlich beeinflusst; während einige PAs zu jeder Jahreszeit ontogenetisch verändert wurden (Retrorsin-N-oxid, Senecionin), konnte dieses für Senecivernin-N-oxid nicht nachgewiesen werden.The common groundsel (Senecio vulgaris L.) is a harmful weed because of its toxic compounds (pyrrolizidine alkaloids, PAs) and its enormous distribution potential in agricultural and horticultural crops (Robinson et al., 2003; BfR, 2007; Wiedenfeld, 2011; Wiedenfeld und Edgar, 2011). During different seasons and in plot-field experiments we have examined the growth parameters and the amount of different PAs of Senecio vulgaris L. related to ontogenetic differences.As already shown for other Senecio species, the PA content in Senecio vulgaris (PAs total, tertiary PAs and PA-N-oxides) is influenced by the developmental stage, depending on the season. In general, there is a tendency for the PA concentration to increase until full flowering and subsequently to decrease again for fruit and seed maturity. In each developmental stage the contents of the N-oxides were higher than the corresponding tertiary PAs. The individual compounds are influenced differently in their concentration: while some PAs are always subject to a significant influence by ontogenesis (retrorsine-N-oxide, senecionine), influences for senecivernine-N-oxide could only be detected in one season
Assessing the efficacy of bee promoting measures (Hymenoptera, Apiformes) along an urban-rural gradient
Get PDFDie Bedeutung von Städten als Refugien für Bestäuberinsekten zeichnet sich zunehmend ab. Bienen spielen eine wichtige Rolle in der Stabilisierung von Ökosystemen, sowohl im ruralen als auch im urbanen Kontext. Während bienenfördernde Maßnahmen vor allem im landwirtschaftlichen bzw. ruralen Kontext untersucht wurden, besteht eine große Wissenslücke in Bezug auf die Effektivität solcher Maßnahmen in urbanen Landschaften. Ziel dieses Übersichtsartikels ist es, einen Überblick über jüngere Forschungsaktivitäten basierend auf der im Peer-Review-Verfahren publizierten Literatur zu geben, um Empfehlungen für zukünftige Forschungsprojekte zum Schließen dieser Wissenslücke abzuleiten. Während Studien zu Saatgutmischungen hauptsächlich auf Ernährungsaspekte abzielen, sind Studien zu Staudenpflanzungen auf vergleichsweise wenige Pflanzentaxa beschränkt. Die Durchführung vergleichbarer Studien zu Effekten von Baumpflanzungen auf Bienenpopulationen wird durch eine geringgradige Methodenstandardisierung erschwert. Der Naturschutzwert künstlicher Niststrukturen in Städten bedarf weiterer Erforschung, insbesondere im Hinblick auf bodennistende Bienenarten. Während mehrere Fallstudien auf eine Ernährungsfunktion von Gründächern für urbane Bienenpopulationen hindeuten, sind die Ergebnisse bezüglich der vertikalen Isolation von Gründächern nicht eindeutig. Zahlreiche Faktoren wurden identifiziert, die die Diversität und Populationsstruktur im urbanen Raum auf lokaler und Landschaftsebene beeinflussen. Der relevante Landschaftsmaßstab wird in den meisten Fällen durch Radien zwischen 500 und 1000 m repräsentiert. Zukünftige Studien, deren Versuchsaufbau einen kontinuierlichen und vollständigen Urbanisierungsgradienten berücksichtigt, werden von Nutzen sein, um die zahlreichen Ergebnisse zu bienenfördernden Maßnahmen in Agrarlandschaften mit den bislang wenigen Ergebnissen in urbanen Landschaften zu vergleichen. Studien, die die genetische Struktur von Bienenpopulationen im Hinblick auf Urbanisierung berücksichtigen, repräsentieren bislang nur einen sehr kleinen Ausschnitt der Bienenvielfalt. Die Weiterentwicklung molekularbiologischer Methoden könnte in naher Zukunft neuartige Werkzeuge zur Bewertung des Erfolgs bienenfördernder Maßnahmen im Hinblick auf die Habitatkonnektivität bereitstellen.Cities are emerging as refugia for pollinators, among which bees play a pivotal role for maintaining ecosystem functioning in agricultural and urban settings. While measures to promote bees have been investigated predominantly in the agricultural or rural context, a wide knowledge gap persists with regard to the effectiveness of such measures within urban landscapes. In order to guide research addressing this lack of knowledge, the aim of this perspective paper is to give an overview of the recent research activities based on the published peer-reviewed literature. While research on flower seed mixtures in general focuses on nutritional aspects, studies on plantings of perennial herbs are relatively limited to few plant taxa. Implementation of comparable case studies investigating the effects of tree plantings on bee populations is hampered by a lack of methodological standardization. The conservation value of providing nesting sites in cities needs to be further investigated, in particular concerning ground-nesting bee species. While several case studies indicate a nutritional supporting function of green roofs for urban bee populations, findings with regard to vertical isolation remain equivocal. Various factors driving bee diversity and population structure in the urban context at the local and landscape scale have been identified, the reported relevant landscape scale being represented by radii between 500 and 1000 m in most cases. Future study designs reflecting a continuous and complete gradient of urbanization will be helpful in comparing results on bee promoting measures in agricultural landscapes (which are numerous) to urban settings (which are still encountered much less frequently). Studies looking into the genetic structure of bee populations with regard to urbanization so far represent only a tiny fraction of bee diversity, and the further development of molecular methods could yield novel tools for assessing the success of bee promoting measures in terms of habitat connectivity in the near future
Grapevine trunk disease in German viticulture IV. Spreading of spores of the Esca related fungus Phaeomoniella chlamydospora and the occurrence of foliar Esca-symptoms in German vineyards
No full textThe anamorphic fungus Phaeomoniella chlamydospora (Pch), related to Grapevine trunk diseases (GTDs) such as "Petri disease" and Esca, was originally restricted to the Mediterranean area but can now be found worldwide. GTDs are the most destructive diseases in vineyards causing high losses every year. As there are no effective fungicides available it is important to understand the epidemiology of this fungus. To investigate the occurrence and distribution of Pch in the field, spore traps were placed in two selected vineyards located at the Julius Kühn-Institut (JKI) in Siebeldingen, Germany, for three consecutive years. Plots were planted with cultivars \u27Chardonnay\u27 and the fungus resistant cultivar \u27Phoenix\u27. Analysis of the traps was performed by a specifically developed nested-PCR approach. As a result it was proven that Pch is present in the vineyards throughout the whole year, including wintertime. The occurrence of Pch conidia during the winter months is a central issue as the annual pruning of vines is done in the winter season and pruning wounds are supposed to be the main entry point for this pathogen. During the three year survey also symptom appearance, both chronic and apoplectic, on leaves as well as weather conditions have been recorded. Symptoms were evident in both vineyards; however, no clear correlation was obtained between symptoms and spore flight. High temperatures combined with low humidity may have a negative impact on spore dispersal, while cold temperatures such as in wintertime have no negative effect on the appearance of spores
Dynamics of Scaphoideus titanus population in southern South Tyrol (Italy) and detection of Grapevine Flavescence Dorée phytoplasma in the insect with a multiplex real-time PCR
Get PDFIn South Tyrol the population of Scaphoideus titanus, the vector of Grapevine Flavescence dorée phytoplasma (FD), has been steadily increasing since 2010. The present work provides an overview of the monitoring activity of Scaphoideus titanus in South Tyrolean vineyards coupled with the description of a sensitive and reliable detection method of FD in the insect vector. We have developed an endogenous control of Scaphoideus titanus to be used in a multiplex real-time PCR, amplifying the map gene of FD phytoplasma. We present evidence on the performance of this new vector reference and its compatibility with FD detection
Growth, development and quality of Passiflora tripartita var. mollissima fruits under two environmental tropical conditions
Get PDFThe curuba (Passiflora tripartita var. mollissima) is an important Andean fruit in bioprospecting industries because of its pleasant taste and aroma, antioxidant potential and sedative action. The objective of this study was to evaluate the development of curuba plants and the physicochemical characteristics of fruits under two environmental tropical altitudinal conditions. Crops were established in a low zone (2,006 m.a.s.l.) and a high zone (2,498 m.a.s.l.) in the municipality of Pasca (Cundinamarca, Colombia). Phenological monitoring was carried out in the principal growth stages. The weight, length, diameter, color, firmness, pH, total soluble solids, total titratable acidity and organic acid content were measured in the fruits. Climatic parameters were monitored during the crop cycle, and base temperatures and thermal times were estimated. The temperature and photosynthetically active radiation (PAR) were the climatic factors that had the greatest effect on plant development. The base temperatures of growth of the primary branches, floral buds and fruits were 4.3°C, 3.1°C and 0.01°C, respectively. In the lower zone, the plants accumulated more growing degree days than in the upper zone. The fruits in the upper zone presented a higher weight, total titratable acidity and ascorbic acid content. The plants presented a marked response to the differential agroecological conditions of the two sites
Antimicrobial compounds from Athyrium sinense damage the cell membrane of Clavibacter michiganensis subsp. sepedonicus
Get PDFClavibacter michiganensis subsp. sepedonicus is a widely distributed pathogen that causes ring rot of potato. Antimicrobial activity assays demonstrated that petroleum ether extracts from Athyrium sinense was a fraction with strong activity against C. michiganensis subsp. sepedonicus. The aim of this study was to determine the chemical compounds in this fraction, and to investigate the antimicrobial mechanism. The dominant components were palmitic acid (25.78%), neophytadiene (13.66%), linoleic acid (8.95%), oleic acid (8.20%), phloretic acid (7.48%), methyl sinapate (6.92%), e-11-hexadecen-1-ol (6.10%), 1-hexadecanol (5.41%), and stearic acid (2.87%). Electron micrographs showed that application of the petroleum ether extracts seriously altered the morphology of C. michiganensis subsp. sepedonicus. Release of alkaline phosphatase and leakage of intracellular soluble protein confirmed that the integrity of the cell membrane was destroyed. Furthermore, ATPase activity, intracellular DNA content, and cell membrane potential were all demonstrated to be inhibited. In addition, the petroleum ether extract penetrated through the damaged cell membrane, and subsequently disrupted the cell cycle of the bacteria. We concluded that the petroleum ether fraction of ethanolic Athyrium sinense extracts was effective to inhibit C. michiganensis subsp. sepedonicus by damaging the cell membrane, and could be used as a natural alternative for C. michiganensis subsp. sepedonicus control
Predicting wild bee sensitivity to insecticides utilizing phylogenetically controlled inter-species correlation models
Get PDFRecent experiences with bumblebee (Bombus terrestris) semi-field tunnel testing following ICPPR Non-Apis 2016 and 2017 workshop recommendations to investigate the insecticide chlorantraniliprole
Get PDFThe study investigated the potential impact of the insecticide chlorantraniliprole (Coragen® brand) on the bumble bee (Bombus terrestris L.) under semi-field conditions in Phacelia tanacetifolia in Germany based on ringtest protocols from the ICPPR Non-Apis workshops (2016 and 2017). The P. tanacetifolia crop was grown in soil treated with the predicted 20-year plateau concentration of chlorantraniliprole in the top 20 cm of soil (equivalent to a predicted 20-year plateau concentration of 0.088 mg a.s./kg). Additionally, two chlorantraniliprole applications at 60 g a.s./ha were made in the chlorantraniliprole treatments (T1 and T2). In T1 both applications took place before P. tanacetifolia flowering at BBCH 51-55 and BBCH 55-59. In T2 one application was conducted before P. tanacetifolia flowering at BBCH 55-59 and one application during P. tanacetifolia flowering and during daily bee flight at BBCH 61-62. The application in the control (C) and reference item treatment (R) (400 g dimethoate a.s./ha) was carried out during full P. tanacetifolia flowering and bumble bee flight. The bumble bee colonies were exposed to the treated flowering P. tanacetifolia crop for 20 days in the tunnels and afterwards the colonies were kept on a monitoring site. The results of this study indicate no significant differences between the chlorantraniliprole treatment groups T1 and T2 and the control regarding all parameters assessed (i.e. mortality in the colonies and in the tunnels, flight activity at the hive entrance, hive weight development, condition of the colonies and production of young queens and males). Overall, no effects of chlorantraniliprole on bumble bee B. terrestris colonies including queen/male production, adult and larval survival and forager flight activity were found.The study investigated the potential impact of the insecticide chlorantraniliprole (Coragen® brand) on the bumble bee (Bombus terrestris L.) under semi-field conditions in Phacelia tanacetifolia in Germany based on ringtest protocols from the ICPPR Non-Apis workshops (2016 and 2017). The P. tanacetifolia crop was grown in soil treated with the predicted 20-year plateau concentration of chlorantraniliprole in the top 20 cm of soil (equivalent to a predicted 20-year plateau concentration of 0.088 mg a.s./kg). Additionally, two chlorantraniliprole applications at 60 g a.s./ha were made in the chlorantraniliprole treatments (T1 and T2). In T1 both applications took place before P. tanacetifolia flowering at BBCH 51-55 and BBCH 55-59. In T2 one application was conducted before P. tanacetifolia flowering at BBCH 55-59 and one application during P. tanacetifolia flowering and during daily bee flight at BBCH 61-62. The application in the control (C) and reference item treatment (R) (400 g dimethoate a.s./ha) was carried out during full P. tanacetifolia flowering and bumble bee flight. The bumble bee colonies were exposed to the treated flowering P. tanacetifolia crop for 20 days in the tunnels and afterwards the colonies were kept on a monitoring site. The results of this study indicate no significant differences between the chlorantraniliprole treatment groups T1 and T2 and the control regarding all parameters assessed (i.e. mortality in the colonies and in the tunnels, flight activity at the hive entrance, hive weight development, condition of the colonies and production of young queens and males). Overall, no effects of chlorantraniliprole on bumble bee B. terrestris colonies including queen/male production, adult and larval survival and forager flight activity were found