Explaining variability in the production of seed and allergenic pollen by invasive Ambrosia artemisiifolia across Europe

To better manage invasive populations, it is vital to understand the environmental drivers underlying spatial variation in demographic performance of invasive individuals and populations. The invasive common ragweed, Ambrosia artemisiifolia, has severe adverse effects on agriculture and human health, due to its vast production of seeds and allergenic pollen. Here, we identify the scale and nature of environmental factors driving individual performance of A. artemisiifolia, and assess their relative importance. We studied 39 populations across the European continent, covering different climatic and habitat conditions. We found that plant size is the most important determinant in variation of per-capita seed and pollen production. Using plant volume as a measure of individual performance, we found that the local environment (i.e. the site) is far more influential for plant volume (explaining 25% of all spatial variation) than geographic position (regional level; 8%) or the neighbouring vegetation (at the plot level; 4%). An overall model including environmental factors at all scales performed better (27%), including the weather (bigger plants in warm and wet conditions), soil type (smaller plants on soils with more sand), and highlighting the negative effects of altitude, neighbouring vegetation and bare soil. Pollen and seed densities varied more than 200-fold between sites, with highest estimates in Croatia, Romania and Hungary. Pollen densities were highest on arable fields, while highest seed densities were found along infrastructure, both significantly higher than on ruderal sites. We discuss implications of these findings for the spatial scale of management interventions against A. artemisiifolia

ESG megfontolások a kriptovaluták árazásában

INST: Szakdolgozatok (GTK) - Szakdolgozatok (GTK)Dolgozatom célja a kriptovaluták általános megítélésének feltárása, főbb események hatásának vizsgálata az árfolyamukra és az energiafogyasztásuk konzenzus protokollal való összefüggésének bizonyítás

Semi-natural habitat types provide different disservices in terms of weed infestations in European arable fields

There is an increasing interest in the conservation of semi-natural habitat (SNH) because they provide ecosystem services for crop production, environmental protection and society. However, their true value can only be estimated if also the level of disservices is known. The EU FP7 project QuESSA (Quantification of ecological services for sustainable agriculture), aims, among others, to assess disservices provided by semi-natural habitat types by quantifying weed densities and community composition in adjacent arable crops throughout Europe. Weed species have also been classified in relation to how problematic they are in arable crops and how desirable they may be for the provisioning of ecosystem services. Therefore in 2014 and 2015 a total of 62 sunflower fields were selected in Italy and Hungary. Weed composition was determined by scoring density and percentage cover of the species in 14 1m2 plots in each field about 3 weeks after main weed management practices were performed in the crop. The plots were positioned along 2 transects, 10 m apart, at increasing distances into the field. GLM and ANOVA showed that, total weed densities and weed cover were higher next to cropped margins in Hungary while in Italy adjacent SNH type did not affect these variables. The hypothesis that increased distance from the SNH decreases weed density of various weed groups (monocots, dicots, annual, and perennials) was confirmed in Italy but was not so clear in Hungary. In Italy increased weed species richness and abundance were found in fields surrounded by increasing SNH percentage in the 1km radius landscape sector. The preliminary analyses indicate that the response of weed communities to SNH is area specific.. This project has received funding from the European Union’s Seventh Framework Programme for research, technological development and demonstration

Contribution of Glutathione Transferases in the Selective and Light-Dependent Effect of Flumioxazin on Winter Wheat (Triticum aestivum L.) and Its Typical Weed Common Poppy (Papaver rhoeas L.)

Glutathione transferases (GSTs) are enzymes that catalyse modifications and conjugations of a range of organic and often cytotoxic compounds. GST enzymes with many functions—such as their conjugation activity against herbicides and their metabolites—can be induced and show light and circadian determination. The enzyme family, which is widespread in its function, also shows great diversity in its structure, which has been linked to its enzyme kinetic characteristics and physiological role at many points. In this study, we aimed to find out the role of different glutathione transferases in the herbicide responses to flumioxazin, as well as to determine how the antioxidant and detoxification response to herbicide treatment changes in the presence and absence of light. One of the herbicide treatments was carried out during the light period in the morning (9:00 a.m.), and the other before the end of the dark period (4:00 a.m.). The decrease in the maximal quantum efficiency of PS II and the reduction in the chlorophyll concentration supported the effect of the herbicide on Papaver rhoeas. In the guaiacol peroxidase POD and GST activity, there were large differences between the cultivated plants and the weed; both enzyme activities were much higher in the case of wheat. According to the activity of the antioxidant defence enzymes and GST gene expression data, the application of the photosynthesis inhibitor herbicide, flumioxazin, in the dark could allow the wheat antioxidant defence to switch on before the herbicide effect could appear in the light period. Phi and tau group GSTs were transcriptionally upregulated by the treatments in wheat plants (especially TaGSTU1B), while fewer changes were detectable in poppy weed (PrGSTU4). Based on our results, in the background of the greater and more successful response to flumioxazin may be—among other things—the higher degree of variability of the GSTU genes of wheat compared to poppies