About: Thistle is a research topic. Over the lifetime, 754 publications have been published within this topic receiving 10543 citations. The topic is also known as: Cirsium discolor.
TL;DR: The possibility that recent increases in atmospheric CO(2) during the 20th century may have been a factor in the selection of invasive weedy species is suggested.
Abstract: The response of plant species to future atmospheric carbon dioxide concentrations [CO(2)] has been determined for hundreds of crop and tree species. However, no data are currently available regarding the response of invasive weedy species to past or future atmospheric [CO(2)]. In the current study, the growth of six species which are widely recognized as among the most invasive weeds in the continental United States, Canada thistle (Cirsium arvense (L.) Scop.), field bindweed (Convolvulus arvensis L.), leafy spurge (Euphorbia esula L.), perennial sowthistle (Sonchus arvensis L.), spotted knapweed (Centaurea maculosa Lam.), and yellow star thistle (Centaurea solstitialis L.) were grown from seed at either 284, 380 or 719 micromol mol(-1) [CO(2)] until the onset of sexual reproduction (i.e. the vegetative period). The CO(2) concentrations corresponded roughly to the CO(2) concentrations which existed at the beginning of the 20th century, the current [CO(2)], and the future [CO(2)] projected for the end of the 21st century, respectively. The average stimulation of plant biomass among invasive species from current to future [CO(2)] averaged 46%, with the largest response (+72%) observed for Canada thistle. However, the growth response among these species to the recent [CO(2)] increase during the 20th century was significantly higher, averaging 110%, with Canada thistle again (+180%) showing the largest response. Overall, the CO(2)-induced stimulation of growth for these species during the 20th century (285-382 micromol mol(-1)) was about 3x greater than for any species examined previously. Although additional data are needed, the current study suggests the possibility that recent increases in atmospheric CO(2) during the 20th century may have been a factor in the selection of these species.
TL;DR: The results emphasize that biological diversity and ecological functions within a plant-insect community are not only affected by local habitat factors but also by large-scale landscape characteristics, and to improve future agri-environmental schemes for biodiversity conservation and biological control large- scale landscape effects and their scale-dependency should be considered.
Abstract: The effects of local habitat and large-scale landscape factors on species diversity and species interactions were studied using the insect community in stems of the creeping thistle Cirsium arvense. Thistle abundance was higher in fallows than in crop fields and field margins, with fallows providing 67% of thistle abundance within 15 study areas on a landscape scale. Species richness of the herbivores was positively related with thistle abundance, parasitoid species richness was influenced by habitat type and was positively correlated with herbivore species richness. The abundance of herbivores and parasitoids was affected by local factors such as habitat type and host abundance, but also by landscape factors such as the percentage of non-crop area and the isolation of habitats. The infestation rate caused by the agromyzid Melanagromyza aeneoventris was positively related to percent non-crop area, whereas the parasitism rate of this fly increased with increasing habitat diversity on the landscape scale. For these two interactions and for total herbivore abundance, a scale-dependency of the landscape effects was found. The results emphasize that biological diversity and ecological functions within a plant-insect community are not only affected by local habitat factors but also by large-scale landscape characteristics. Hence, to improve future agri-environmental schemes for biodiversity conservation and biological control large-scale landscape effects and their scale-dependency should be considered.
TL;DR: Thistle heads and emergent insects. Original data on herbivores and parasitoids infesting thistles, stored in a dataset accessible at (URL). Galls induced by herbivore infestations and metamorphosis of larvae into adults within the galls.
Abstract: Original data comes from a project which takes or took place as part of the DFG priority program "Exploratories for large-scale and long-term functional biodiversity research". The data is stored together with descriptive metadata, in combination called a dataset, in the project repository (https://www.bexis.uni-jena.de). Species information was extracted from that original dataset. The second paragraph is part of the metadata of the original dataset. Invertebrate herbivores infest different plant organs of thistle species. Furthermore, parasitoid species infest herbivores that feed on thistles. Often such infestations induce generation of plant galls. Within the galls invertebrate larvae metamorphose and emerge as adult imagos.
TL;DR: Field bindweed, Canada thistle, and tall morningglory metabolized the parent glyphosate to aminomethylphosphonic acid to a limited extent and 14C applied to excised leaves had disappeared within 25 days.
Abstract: Summary:
The pattern and extent of 14C-glyphosate [N-(phosphonomethyl)glycine] translocation from the treated leaf and metabolism of 14C-glyphosate were studied in field bindweed (Convolvulus arvensis L.), hedge bindweed (Convolvulus sepium L.). Canada thistle [Cirsium arvense (L.) Scop.] tall morning glory [lpomoea purpurea (L.) Roth.] and wild buckwheat (Polygonum convolvulus L.). 14C was translocated throughout the plants within 3 days with accumulation in the meristematic tips of the roots and shoots evident. Cross and longitudinal sections of stems and roots showed that the 14C was localized in the phloem. Field bindweed translocated 3–5% of the applied 14C from the treated leaf, hedge bindweed 21.6%, Canada thistle 7.8%, tall morningglory 6.5%, and wild buckwheat 5%. Field bindweed, Canada thistle, and tall morningglory metabolized the parent glyphosate to aminomethylphosphonic acid to a limited extent. This metabolite made up less than 15% of the total 14C. Of the total 14C applied to excised leaves, 50% had disappeared within 25 days.