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Effect of potassium fertilization on the contents of antioxidants in three cocktail tomato cultivars
No full textTomatoes are an important source of health beneficial phytochemicals, which act as antioxidants such as ascorbic acid, phenolic compounds, carotenoids, and tocopherols. The content of antioxidants is influenced, among others, by abiotic stress factors, like the nutritional status. Potassium (K) is a macronutrient, which is essential for several physiological functions in plants, for example, translocation of assimilates, activation of enzymes, maintenance of turgescence, and stomata regulation. The aim of this study was to investigate the effect of increasing K fertilization on the concentration of antioxidants in cocktail tomatoes. Therefore, three tomato cultivars (Primavera, Resi, and Yellow Submarine), grown in an outdoor pot experiment, were fertilized with increasing K doses for two consecutive years. It was confirmed that antioxidants in tomato fruit can be affected by the K regime, but was also shown that other factors may reduce or even inverse those effects when cultivation takes place in an uncontrolled outdoor environment. Most consistent K fertilization effects were found for naringenin, p-coumaric acid and caffeic acid. However, enrichment of tomatoes with antioxidants by K fertilization is cultivar dependent and, therefore, general statements should be avoided
Looking for residues of pesticides in bees, plants and bee products
Get PDFDie chemisch-analytische Bestimmung von Schadstoff-Rückständen verschiedenen Ursprungs ist essentiell für die Expositionsermittlung im Rahmen der Aufklärung von Bienenvergiftungen und von Studien zur Bewertung des Risikos für Bienen. Die etablierte und umfassend validierte Multimethode ist sowohl zur Bestimmung von Rückständen in Bienen- und Pflanzenproben als auch für diverse Bienenprodukte (z.B. Pollen/Bienenbrot, Gelée Royal oder Wachs) sehr gut geeignet. Die Zusatzversuche zur Methodenüberprüfung wurden mit dem jeweils aktuellen Wirkstoffspektrum der Untersuchungsstelle für Bienenvergiftungen und verschiedenen Zusatzkonzentrationen durchgeführt. Die Zusatzkonzentrationen wurden so gewählt, dass möglichst alle Wirkstoffe des Untersuchungsprogramms sowohl mit LC‑MS/MS als auch mit GC‑MS bestimmt werden konnten. Mit den Matrices „Bienen“ und „Raps“ wurden Validierungen mit den Konzentration 1, 10 und 50 μg/kg durchgeführt. Die Quantifizierung wurde mit Matrix-Standards vorgenommen, um die durch Probeninhaltsstoffe hervorgerufenen Matrixeinflüsse zu reduzieren.Für 240 Wirkstoffe (vor allem Insektizide, Fungizide), die 2011 im Screening-Programm enthalten waren, lagen die Wiederfindungsraten mit Bienenmatrix beim Zusatzniveau von 10 μg/kg überwiegend zwischen 70% und 110%, mit relativen Standardabweichungen unter 15%.The chemical-analytical determination of pollutant residues of various origins is essential for the determination of exposure in the context of the investigation of bee poisoning and of studies to assess the risk to bees. The established and extensively validated multi-method is very well suited for the determination of residues in bee and plant samples as well as for various bee products (e.g. pollen/bee bread, royal jelly or wax). The validation experiments were carried out with the current spectrum of active substances of the investigation center for bee poisoning incidents and various concentration levels. The concentrations were chosen so that as far as possible all active substances of the investigation program could be determined with LC-MS/MS and GC-MS. Validations with the concentrations 1, 10 and 50 μg/kg were carried out with the matrices “bees” and “rape”. The quantification was carried out with matrix standards in order to reduce the matrix influences caused by sample ingredients. For 240 active substances (especially insecticides, fungicides), included in the screening program in 2011, the recovery rates with the bee matrix at the concentration level of 10 μg/kg were mostly between 70% and 110%, with relative standard deviations below 15%
Effects of tank mixtures of plant protection products on honey bees and possible physiological interactions
Get PDFIm Zuge der Nahrungssuche werden Bestäuber, wie Honigbienen, unter Umständen einer Vielzahl von Pflanzenschutzmitteln (PSM) ausgesetzt. Während die Effekte einzelner PSM auf Bienen im Rahmen des Zulassungsprozesses umfangreich geprüft werden, erfolgt für Tankmischungen eine routinemäßige Risikobewertung i.d.R. nur für Insektizide und bekannte potentiell synergistisch wirkende Mischungspartner. Aus ökonomischen und arbeitswirtschaftlichen Gründen kommen Mischungen von PSM dennoch häufig zum Einsatz. In einigen Fällen führen Interaktionen zwischen den Mischungspartnern hierbei zu unerwünschten additiven oder synergistischen Effekten. Insbesondere für Pyrethroide und Neonikotinoide in Mischung mit Ergosterol-Biosynthese-hemmenden Azolfungiziden ist das synergistische Potential der Mischtoxizität auf Honigbienen bekannt und wird regulatorisch bereits berücksichtigt. Diese Wirkungssteigerung resultiert aus der Hemmung des Hauptentgiftungsenzyms P450 durch Azolfungizide, sodass das jeweilige Insektizid von den Bienen nicht mehr abgebaut werden kann. Erste Hinweise auf wirkungssteigernde Effekte liegen ebenfalls für Mischungen aus Insektiziden und Zusatzstoffen vor. Für eine realistische Risikobewertung ist ein besseres Verständnis von Mischungseffekten essentiell, das nur über weitere Forschung erreicht werden kann.During foraging bouts pollinators like honey bees may be exposed to multiple plant protection products (PPPs). In contrast to applications of single PPPs the effects of tank mixtures are not routinely evaluated in the risk assessment process of PPPs with the exception of known synergistic insecticides and mixing partners. Due to economical constraints and process efficiency PPP mixtures are commonly used in agricultural practices. However, sometimes interactions among agrochemicals lead to undesirable additive and synergistic effects. Especially mixtures of pyrethroids or neonicotinoids with azole fungicides, which inhibit sterol biosynthesis, have a synergistic potential of negatively affecting honey bees. For such mixtures, regulatory restrictions are already in place. These synergistic effects are associated with azole fungicides inhibiting the main detoxification enzyme P450, which hinders the bee to detoxify the insecticide. Further studies provide first evidence for increased impacts of mixtures of insecticides with adjuvants on honey bees. More research is necessary to better understand mixture toxicity and to implement this knowledge in the risk assessment
Propagation potential for the conservation of Brackenridgea zanguebarica Oliv., a critically endangered plant species endemic to Vhembe District in Limpopo Province (South Africa)
Get PDFBrackenridgea zanguebarica Oliv. is an important multipurpose tree valued for its medicinal uses in Vhembe District. The unsustainable harvesting coupled with poor seed germination in the wild is threatening its regeneration; which poses a challenge in efforts to its conservation. This study was conducted to identify suitable methods for propagating B. zanguebarica species using seeds and stem cuttings. Seeds propagation was carried out to evaluate the effect of various pre-treatments. Vegetative propagation was tested to assess if B. zanguebarica could be successfully propagated via stem cuttings with appropriate treatments. The results showed that B. zanguebarica seeds did not germinate at all under any of the conditions tested. Stem cuttings presented a possibility of propagating this species despite the poor results obtained, where 51% of cuttings across all treatment produced buds and 17% only developed leaves without any root development. The growth media had insignificant (P > 0.05) effect on some vegetative growth parameters, while growth hormones showed significant (P < 0.05) effect in all the vegetative growth parameters of stem cuttings where IAA performed better than IBA and NNA. However, their interaction were significant (P < 0.05) on all the growth parameters of Brackenridgea zanguebarica stem cuttings except on the percentage of cuttings that produced buds (P = 0.107). The findings showed that B. zanguebarica is difficult to propagate sexually and asexually, hence, further studies are needed to identify suitable methods for both seed and vegetative propagation of this plant
Predicting potential sites of nine drought-tolerant native plant species in urban regions
Get PDFDrought and water scarcity are serious limiting factors for plant growth and can thus present an obstacle to development of the urban green areas in the cities in particular under climate change. Using native plants is a high-priority option to increase vegetation cover in areas facing global warming and water scarcity. In order to evaluate whether urban areas cover suitable habitats for nine native species in the east of Iran, species distribution models were developed and binary maps were generated. The model output indicated a relatively good performance. Most of the suitable habitats for the plant species are located in north, west and center of the study area. Cercis griffithii had the highest (46.63%) and Acantholimon erinaceum had the lowest (6.29%) proportion of suitable habitats among all studied species in the Khorasan region. Annual precipitation, annual mean temperature, and mean temperature of warmest quarter were the most important environmental variables in determining the potential geographic distribution for these species. Due to similar climateconditions, such as low rainfall, high temperature, low relative humidity and high solar radiation particularly in the summers, our findings showed that Cercis griffithii, Iris songarica and Tamarix ramosissima can be utilized in the development of green areas in the studied regions. According to the output of the species distribution models, planting of Acantholimon erinaceum, Salvia abrotanoides and Rosa canina is not advisable in the South and Razavi Khorasan provinces
Current experimental advances from the French Methodological Bee Group. New improvement for future repro-toxicity tests
Get PDFProgress on the Osmia acute oral test - findings of the ICPPR Non-Apis subgroup solitary bee laboratory testing
Get PDFRisk of exposure in soil and sublethal effects of systemic insecticides on ground-nesting hoary squash bees
Get PDFMeasures taken - the Swiss national action plan for bee health
Get PDFThe annual winter losses of honey bees in Switzerland vary between 9% and 23% during the years 2008 to 2019 and are exceeding the as normal defined 10% level. The causes for the losses can have several reasons. However, one of the main reasons is the infection of the honeybees with the Varroa mite. Therefore, a health services for bees was founded to offer education programs for beekeepers and to support beekeepers in preventing and combating diseases. Switzerland further decided in 2014 to implement an action plan to promote the health of bees. Measures have been taken in the areas of disease prevention, promotion of food supply and reduction of risks from plant protection products. Immediate measures have been implemented such as the inclusion of a flowering strip in the Direct Payments Ordinance and measures to protect bees from plant protection products. Switzerland is actively involved in the development of new OECD test guidelines to evaluate the acute and chronic risk to honey- and wild bees. Honey and wild bees play an important role in pollination of agricultural crops and wild plants. The current situation is in evaluation to decide if further measures are needed.The annual winter losses of honey bees in Switzerland vary between 9% and 23% during the years 2008 to 2019 and are exceeding the as normal defined 10% level. The causes for the losses can have several reasons. However, one of the main reasons is the infection of the honeybees with the Varroa mite. Therefore, a health services for bees was founded to offer education programs for beekeepers and to support beekeepers in preventing and combating diseases. Switzerland further decided in 2014 to implement an action plan to promote the health of bees. Measures have been taken in the areas of disease prevention, promotion of food supply and reduction of risks from plant protection products. Immediate measures have been implemented such as the inclusion of a flowering strip in the Direct Payments Ordinance and measures to protect bees from plant protection products. Switzerland is actively involved in the development of new OECD test guidelines to evaluate the acute and chronic risk to honey- and wild bees. Honey and wild bees play an important role in pollination of agricultural crops and wild plants. The current situation is in evaluation to decide if further measures are needed