7850 research outputs found
Sort by
NIRS-based detection and removal of pyrrolizidine alkaloid containing weeds in crop plants after harvest – PA-NIRSort
Get PDFPyrrolizindinalkaloide (PAs) sind lebertoxisch wirkende, sekundäre Pflanzeninhaltsstoffe, die den Pflanzen zum Schutz vor Fraßfeinden dienen. In den letzten Jahren sind PAs verstärkt in den Fokus gerückt, da sie als ungewollte Beiernte besonders in Bio- und Kindertees zu zum Teil sehr hohen Alkaloid-Belastungen führten. Inzwischen wurden strenge PA-Grenzwerte vom Bundesinstitut für Arzneimittel und Medizinprodukte (BfArM) publiziert, denn Arzneipflanzen können mit PA-haltigen Unkräutern wie verschiedenen Kreuzkraut-Arten, Gemeinem Natternkopf, Ackervergißmeinnicht, Gewöhnlicher Hundszunge, Wasserdost oder Borretsch verunreinigt sein und so über Arznei- oder Aroma-Tees Menschen potenziell gefährden (BfArM, 2016). Durch diese strengen Grenzwerte genügen unter Umständen vier bis fünf PA-bildende Pflanzen des Gemeinen Greiskrauts (Senecio vulgaris) je Hektar Anbaufläche, um die Verkehrsfähigkeit einer Tonne Medizinaldroge zu gefährden. Dies zu verhindern erfordert eine engmaschige regelmäßige Feldkontrolle und mechanisches Unkrautentfernen, das unter ökonomischen Aspekten kaum realisierbar ist. Daher kommt einer, der Ernte nachgelagerten Qualitätskontrolle zum Entfernen potentieller PA-Beikräuter eine besonders wichtige Rolle zu.
Ziel des im März 2019 gestarteten, von der Fachagentur für Nachwachsende Rohstoffe (FNR) geförderten Verbundprojekts des Julius Kühn-Instituts Berlin (Institut für Ökologische Chemie, Pflanzenanalytik und Vorratsschutz) und des Fraunhofer-Institut für Optronik, Systemtechnik und Bildauswertung (IOSB) ist die Entwicklung einer leistungsfähigen Detektionsmethode auf Basis von Hyperspektral-Nah-Infrarot-Spektroskopie (hyperspektral-NIRS) zur Erkennung von Verunreinigungen durch PA-haltige Pflanzen(teile) im Erntegut von Arznei- und Gewürzpflanzen. In Kombination mit einer gekoppelten Sortiereinheit (beispielsweise über Druckluftimpulse) soll so eine Abtrennung unerwünschter und potentiell toxischer Beikräuter erzielt werden. Am Ende des Projektes soll ein Prototyp zur echtzeitfähigen Reinigung der Erntechargen verschiedener Arznei- und Gewürzpflanzen vorgestellt werden. Ähnliche Systeme sind bereits in der Kunststoff-Abfallsortierung bzw. der Qualitätskontrolle von Weinbeeren auf Basis des Oechsle-Grades etabliert (Freund et al., 2015). Angestrebt wird ein Durchsatz von bis zu 1,5 t/h. Mit einer solchen automatisierten Sortiertechnik ließen sich die gesundheitlichen Risiken durch PA-verunreinigte Arzneipflanzenprodukte für die Anbauer und Verarbeiter von Arzneipflanzen ökologisch und ökonomisch effizient reduzieren. Dies würde auch eine Sicherung der qualitativ hochwertigen und konkurrenzfähigen Produktion pflanzlicher Arzneimittel in Deutschland bedeuten.
Erste Ergebnisse zeigen, dass eine Klassifizierung der Pflanzenarten mittels NIR-Spektroskopie zuverlässig möglich ist. Um solche Bildanalysen auch in Echtzeit durchführen zu können, werden die zu verarbeitenden Datenmengen mittels multifaktorieller Datenanalyse auf entscheidende spektrale Merkmale (Faktoren) reduziert.The general objective of the project is the development of an efficient sorting system based on hyperspectral near-infrared spectroscopy (NIRS) for the detection and separation of impurities by pyrrolizidine alkaloid (PA)-containing plant-derived contaminations in cultural plants, e.g. medicinal and aromatic plants. PAs are liver-toxic secondary metabolites that protect plants from predators and have drawn more attention in recent years after harmful concentrations were found in medicinal teas. By now, the German Federal Institute for Drugs and Medical Devices (BfArM) has published strict PA limit values because medicinal plants can be contaminated with PA-containing weeds such as various types of ragwort, groundsel, common viper\u27s head, field forget-me-not, common dog\u27s tongue, water-east or borage and thus, potentially endanger people with medicinal or aromatic teas (BfArM, 2016). Four to five PA-containing plants e.g of Senecio vulgaris per hectare are sufficient to contaminate one ton of the drug by exceeding the critical value of maximum uptake of 0,007 μg PA/kg body weight per day published by HMPC.
The planned process will analyze fresh and dried plant material on a flat-conveyer using hyperspectral NIR spectroscopy to detect impurities in the crop. After identification, contaminants should be removed by a sorting technique, e.g. using compressed air pulses. Similar systems have already been established in plastic waste sorting and quality control, for example for grapes (Freund et al., 2015). The aim is to achieve a high throughput of up to 1.5 t/h with such an automated sorting technology, the health risks posed by PA-contaminated medicinal plant products could be reduced ecologically and economically efficient for cultivation and processing of medicinal plants. This would also mean safeguarding high-quality and competitive plant-derived drug production in Germany.
First results show that a classification of target plant species and contaminating groundsel using NIR spectroscopy succeeds for various medicinal plants. To be able to carry out such image analyses in real-time, the amount of data to be processed will be reduced to the decisive factors using multifactorial data analysis
Sammlung alter Apfelsorten am Standort des Lehr- und Versuchszentrums Gartenbau in Erfurt – seit 2018 als Mitglied der Deutschen Genbank Obst
Get PDFPotassium fertilization in relation to downy mildew disease incidence in grape leaves
Get PDFInfluence of different sources of potassium and their method of application was studied on incidence of downy mildew infection in grape leaves of \u27Sharad Seedless\u27 (syn: \u27Kishmish Chorni\u27). The total phenolic content and individual phenolic acids were analysed from healthy and downy mildew infected leaves of \u27Sharad Seedless\u27 and the degree of downy mildew infection was well correlated with potassium content in the petioles. Different sources and method of potassium application had significant effect on Phenylalanine ammonia-lyase (PAL) enzyme activity and preformed phenols in healthy vines. Significant increase in PAL enzyme activity, total phenols and individual phenolic acids was registered with increase in disease severity. Magnitude of percent change in PAL enzyme activity and total phenolic content was highest in vines with maximum disease infection. Among the phenolic acids, o-Coumaric acid, p-Coumaric acid have a definite role in disease resistance. We could also observe the variation in disease severity in vines which received different sources of potassium which was supplied in different quantities whether through soil and/or through fertigation
Evolution of antioxidant capacity in seeds and skins during grape maturation and their association with proanthocyanidin and anthocyanin content
Get PDFIn order to investigate the antioxidant activity in seeds and skins during grape maturation and their relation with anthocyanin and proanthocyanidin content, two Portuguese red grape varieties, \u27Touriga Nacional\u27 and \u27Tinta Roriz\u27 were studied. For antioxidant activity analysis, one analytical method was used (ABTS method). Different proanthocyanidins fractions according to their degree of polymerization were analyzed, while 13 different individual anthocyanins were evaluate by HPLC as well. During the maturation period the antioxidant activity content quantified from the different grape berry fractions was characterized by a general decrease with a slight oscillation in the early stages of maturation, followed by a stabilization and slight increase of the values in the last weeks of ripening. Similar evolution was observed for the different proanthocyanidins fractions quantified. For the individual anthocyanins, in general the evolution was characterized by a slowly increase in the first 3 weeks of ripening process, followed by a marked increase and finally a slight decrease or stabilization in the last weeks of ripening. Finally, high linear positive correlations between proanthocyanidin fractions and the antioxidant activity evolution during the grape maturation were obtained while for the individual anthocyanins a high negative correlation values was quantified
The homing flight method to assess the effect of sublethal doses of plant protection products on the honey bee in field conditions: results of the ring tests
Get PDFDust drift from treated seeds during seed drilling: comparison of residue deposition in soil and plants
Get PDFICPPR WG Semi-field and field Report and Discussion
Get PDFThe ICPPR Semi-Field/Field Testing (SF/FT) workgroup consists of several ‘writing groups’ that are focused developing technical guidance that is focused on 4 separate but related topics: 1) designing and conducting pollen and nectar residue studies, 2) conducting large scale colony feeding studies, 3) updating guidance for conducting semi-field tunnel studies, and 4) design and interpretation of full field studies with bees. What follows is the current status of each of these activities.The ICPPR Semi-Field/Field Testing (SF/FT) workgroup consists of several ‘writing groups’ that are focused developing technical guidance that is focused on 4 separate but related topics: 1) designing and conducting pollen and nectar residue studies, 2) conducting large scale colony feeding studies, 3) updating guidance for conducting semi-field tunnel studies, and 4) design and interpretation of full field studies with bees. What follows is the current status of each of these activities
Lethality of Imidacloprid and Fipronil on Apis mellifera: a retrospective on the French case
Get PDFThe aim of this study is to draw a retrospective analysis on the lethality of imidacloprid (Gaucho®) and fipronil (Régent® TS) on Apis mellifera between 1992 and 2016 in France. Early monitoring reports in the 1992-2002 period notified these two embedded insecticides to be at the origin of massive colony collapse disorders. Ecotoxicological analyses based on the LD50 of imidacloprid and fipronil highlighted their differential lethality by both contact (imidacloprid: 81 ng/honeybee vs fipronil: 5,9 ng/honeybee) and ingestion (imidacloprid: 3,7 ng/honeybee vs fipronil: 4,2 ng/honeybee) but failed to point imidacloprid’s high solubility as a higher lethal agent. Chemical properties and action mode of these two insecticides originated neural disfunction in the case of imidacloprid, and honeybee brood immune depression for fipronil. Despite the conduction of these monitoring reports and laboratory researches, Fipronil was completely banned in 2005 but Imidacloprid only in 2016.The aim of this study is to draw a retrospective analysis on the lethality of imidacloprid (Gaucho®) and fipronil (Régent® TS) on Apis mellifera between 1992 and 2016 in France. Early monitoring reports in the 1992-2002 period notified these two embedded insecticides to be at the origin of massive colony collapse disorders. Ecotoxicological analyses based on the LD50 of imidacloprid and fipronil highlighted their differential lethality by both contact (imidacloprid: 81 ng/honeybee vs fipronil: 5,9 ng/honeybee) and ingestion (imidacloprid: 3,7 ng/honeybee vs fipronil: 4,2 ng/honeybee) but failed to point imidacloprid’s high solubility as a higher lethal agent. Chemical properties and action mode of these two insecticides originated neural disfunction in the case of imidacloprid, and honeybee brood immune depression for fipronil. Despite the conduction of these monitoring reports and laboratory researches, Fipronil was completely banned in 2005 but Imidacloprid only in 2016
Toxicity of oxalic acid on in vitro reared honeybee larvae
Get PDFVarroa destructor is considered as a serious pest of honeybees (Apis mellifera) and its resistance to acaricides has been reported since the early 1990s. Because large colony loses are yearly reported from over the world, new methods of treatment for Varroa mites are still in focus of many scientists. In our bioassay, we determined the lethal concentration 72 h LC50 of 2.425% oxalic acid solution following single spray exposure of honeybee larvae under laboratory conditions (Guideline OECD 237, 2013).Varroa destructor is considered as a serious pest of honeybees (Apis mellifera) and its resistance to acaricides has been reported since the early 1990s. Because large colony loses are yearly reported from over the world, new methods of treatment for Varroa mites are still in focus of many scientists. In our bioassay, we determined the lethal concentration 72 h LC50 of 2.425% oxalic acid solution following single spray exposure of honeybee larvae under laboratory conditions (Guideline OECD 237, 2013)