34 research outputs found

    Geographic variation in floral scent of Echinopsis ancistrophora (Cactaceae); evidence for constraints on hawkmoth attraction

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    Variation in floral phenotype (color, depth, nectar) suggests incipient specialization for bee or hawkmoth pollination across the geographic distribution of Echinopsis ancistrophora, with flower depth ranging from 4.5 to 24 cm. We used chemical and behavioral analyses to test whether fragrance has evolved in concert with morphology in these Andean cacti. Floral scent (145 total compounds) was collected using dynamic headspace methods and analyzed with gas chromatographyÁmass spectrometry, revealing subspecies-specific odors dominated by sesquiterpenes in E. ssp. ancistrophora and arachnacantha and fatty acid derivatives or aromatics in E. ssp. cardenasiana and pojoensis. Compounds indicative of sphingophily were not consistently found in moth-pollinated plants, and total scent emissions were significantly lower in populations with nocturnal anthesis. In wind tunnel assays, Manduca sexta moths were attracted to scent of ssp. ancistrophora from both bee and hawkmoth-pollinated populations, but not to scent of ssp. cardenasiana. However, hawkmoths were most attracted to the methyl benzoate-dominated scent of a distant relative, Echinopsis mirabilis. Thus, hawkmoth-pollinated descendants of the E. ancistrophora lineage may be phylogenetically constrained to emit weak, sesquiterpene-dominated fragrances that are not optimally attractive to hawkmoths, or floral scent may be under stronger selection by destructive flower visitors

    Overlimiting Current and Shock Electrodialysis in Porous Media

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    Most electrochemical processes, such as electrodialysis, are limited by diffusion, but in porous media, surface conduction and electro-osmotic flow also contribute to ionic fluxes. In this paper, we report experimental evidence for surface-driven over-limiting current (faster than diffusion) and deionization shocks (propagating salt removal) in a porous medium. The apparatus consists of a silica glass frit (1 mm thick with 500 nm mean pore size) in an aqueous electrolyte (CuSO4_4 or AgNO3_3) passing ionic current from a reservoir to a cation-selective membrane (Nafion). The current-voltage relation of the whole system is consistent with a proposed theory based on the electro-osmotic flow mechanism over a broad range of reservoir salt concentrations (0.1 mM - 1.0 M), after accounting for (Cu) electrode polarization and pH-regulated silica charge. Above the limiting current, deionized water (10μ\approx 10 \mu MM) can be continuously extracted from the frit, which implies the existence of a stable shock propagating against the flow, bordering a depleted region that extends more than 0.5mm across the outlet. The results suggest the feasibility of "shock electrodialysis" as a new approach to water desalination and other electrochemical separations.Comment: 39 pages, 9 fig

    Cactaceae at Caryophyllales.org- A dynamic online species-level taxonomic backbone for the family

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    This data paper presents a largely phylogeny-based online taxonomic backbone for the Cactaceae compiled from literature and online sources using the tools of the EDIT Platform for Cybertaxonomy. The data will form a contribution of the Caryophyllales Network for the World Flora Online and serve as the base for further integration of research results from the systematic research community. The final aim is to treat all effectively published scientific names in the family. The checklist includes 150 accepted genera, 1851 accepted species, 91 hybrids, 746 infraspecific taxa (458 heterotypic, 288 with autonyms), 17,932 synonyms of accepted taxa, 16 definitely excluded names, 389 names of uncertain application, 672 unresolved names and 454 names belonging to (probably artificial) named hybrids, totalling 22,275 names. The process of compiling this database is described and further editorial rules for the compilation of the taxonomic backbone for the Caryophyllales Network are proposed. A checklist depicting the current state of the taxonomic backbone is provided as supplemental material. All results are also available online on the website of the Caryophyllales Network and will be constantly updated and expanded in the future. Citation: Korotkova N., Aquino D., Arias S., Eggli U., Franck A., Gómez-Hinostrosa C., Guerrero P. C., Hernández H. M., Kohlbecker A., Köhler M., Luther K., Majure L. C., Müller A., Metzing D., Nyffeler R., Sánchez D., Schlumpberger B. & Berendsohn W. G. 2021: Cactaceae at Caryophyllales.org- A dynamic online species-level taxonomic backbone for the family.-Willdenowia 51: 251-270. Version of record first published online on 31 August 2021 ahead of inclusion in August 2021 issue. Data published through: Http://caryophyllales.org/cactaceae/Checklis

    Autophagy Protein Atg3 is Essential for Maintaining Mitochondrial Integrity and for Normal Intracellular Development of Toxoplasma gondii Tachyzoites

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    Autophagy is a cellular process that is highly conserved among eukaryotes and permits the degradation of cellular material. Autophagy is involved in multiple survival-promoting processes. It not only facilitates the maintenance of cell homeostasis by degrading long-lived proteins and damaged organelles, but it also plays a role in cell differentiation and cell development. Equally important is its function for survival in stress-related conditions such as recycling of proteins and organelles during nutrient starvation. Protozoan parasites have complex life cycles and face dramatically changing environmental conditions; whether autophagy represents a critical coping mechanism throughout these changes remains poorly documented. To investigate this in Toxoplasma gondii, we have used TgAtg8 as an autophagosome marker and showed that autophagy and the associated cellular machinery are present and functional in the parasite. In extracellular T. gondii tachyzoites, autophagosomes were induced in response to amino acid starvation, but they could also be observed in culture during the normal intracellular development of the parasites. Moreover, we generated a conditional T. gondii mutant lacking the orthologue of Atg3, a key autophagy protein. TgAtg3-depleted parasites were unable to regulate the conjugation of TgAtg8 to the autophagosomal membrane. The mutant parasites also exhibited a pronounced fragmentation of their mitochondrion and a drastic growth phenotype. Overall, our results show that TgAtg3-dependent autophagy might be regulating mitochondrial homeostasis during cell division and is essential for the normal development of T. gondii tachyzoites

    A taxonomic backbone for the global synthesis of species diversity in the angiosperm order Caryophyllales

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    The Caryophyllales constitute a major lineage of flowering plants with approximately 12500 species in 39 families. A taxonomic backbone at the genus level is provided that reflects the current state of knowledge and accepts 749 genera for the order. A detailed review of the literature of the past two decades shows that enormous progress has been made in understanding overall phylogenetic relationships in Caryophyllales. The process of re-circumscribing families in order to be monophyletic appears to be largely complete and has led to the recognition of eight new families (Anacampserotaceae, Kewaceae, Limeaceae, Lophiocarpaceae, Macarthuriaceae, Microteaceae, Montiaceae and Talinaceae), while the phylogenetic evaluation of generic concepts is still well underway. As a result of this, the number of genera has increased by more than ten percent in comparison to the last complete treatments in the Families and genera of vascular plants” series. A checklist with all currently accepted genus names in Caryophyllales, as well as nomenclatural references, type names and synonymy is presented. Notes indicate how extensively the respective genera have been studied in a phylogenetic context. The most diverse families at the generic level are Cactaceae and Aizoaceae, but 28 families comprise only one to six genera. This synopsis represents a first step towards the aim of creating a global synthesis of the species diversity in the angiosperm order Caryophyllales integrating the work of numerous specialists around the world

    The uncertain history of an early illustration of Chamaedorea ernesti-augusti

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    [Extract] A high-quality, unattributed illustration of Chamaedorea ernesti-augusti is held in the archives of the Gottfried Wilhelm Leibniz Bibliothek, Hannover, Germany. We investigate its possible creator, its purpose and connection to the palm botanist Hermann Wendland

    Breeding system and estimation of the pollination efficiency on Trichocereus pasacana (Cactaceae) in two populations from Northwest Argentina

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    Volume: 58Start Page: 115End Page: 12

    SISTEMA DE CRUZAMIENTO Y ESTIMACIONES EN LA EFICIENCIA DE POLINIZACI 3N SOBRE TRICHOCEREUS PASACANA (CACTACEAE) EN DOS POBLACIONES DEL NOROESTE ARGENTINO

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    The objectives of this study were to analyse the breeding system and the pollination efficiency in Trichocereus pasacana and their effects on the reproductive fitness in two populations from Northwest Argentina. The first population is in a protected area (Tin Tin Valley), and the other is in a site with high human activity in agriculture and apiculture (Cachi Adentro). The breeding system was analysed by a pollination experiment considering hand self-pollination, hand cross-pollination, natural pollination and automatic self-pollination. The response variables were fruit production, seed production and seed germination. The fruit production permit suggests that the breeding system of T. pasacana is xenogamic and the pollination efficiency is greater in the protected area. However, the seeds from the population with human activity presented higher germination rates. These results permit the suggestion that the Cachi Adentro population presented lower fruit production, but with a higher resource allocation for the seeds. Instead, the Tin Tin population produced a higher number of fruits, but seeds of lower quality.Los objetivos de este estudio fueron analizar el sistema de cruzamiento y la eficiencia de la polinización en Trichocereus pasacana y sus efectos sobre la reproducción. Se trabajó sobre dos poblaciones del noroeste Argentino, una dentro de un área protegida (Valle de Tin Tin) y otra en un sitio con marcada actividad humana de agricultura y apicultura (Cachi Adentro). El sistema de cruzamiento se analizó mediante un experimento donde se evaluó autopolinización manual, polinización cruzada manual, polinización natural y autopolinización automática. Las variables de respuesta fueron producción de frutos, producción de semillas y capacidad germinativa. La producción de frutos permite sugerir que el sistema de cruzamiento de T. pasacana es xenogámico y que la eficiencia de polinización es mayor en el área protegida. Sin embargo, las semillas provenientes de la población con actividad humana presentaron mayores tasas de germinación. Estos resultados permiten sugerir que aunque en Cachi Adentro hubo una menor producción de frutos, esta población presentó una mayor asignación de recursos para las semillas. En cambio, la población de Tin Tin produjo un mayor número de frutos pero con semillas de menor calidad

    The Australian cabbage palm at Herrenhausen Gardens

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    For almost 100 years a single individual of the Australian cabbage palm Livistona australis reigned as the centrepiece of the Royal Gardens palm collection at Herrenhausen in Germany. It is one of the few cultivated glasshouse plants for which horticultural and botanical publications yield a continuous record of its life. Here we tell of the cabbage palm’s unexpected acquisition by Herrenhausen in 1827, aspects of its horticultural and social history spanning almost a century, and its regrettable demise in 1920

    The cactus-specialist bees of the genus brachyglossula Hedicke (Hymenoptera: Colletidae): Notes on host associations and description of a new species

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    The pollen-collecting behavior of three species of the South American Andean bee genus Brachyglossula is reported. Species studied are B. martinezi Trucco Alemn, B. communis Trucco Alemn, and B. ancasti Roig Alsina and Schlumpberger, new species. The new species, which is comparatively described and illustrated, inhabits the isolated mountain range of Sierra de Ancasti, in the province of Catamarca, Argentina. Observation of the bees in the field, and pollen counts from scopal loads strongly support specialization of these bees on the Cactaceae. Members of both major cactus subfamilies, the Opuntioideae and the Cactoideae, are frequently visited and represented in the pollen loads.Fil: Roig Alsina, Arturo Hernan. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Schlumpberger, Boris O.. Ludwig Maximilians Universitat; Alemani
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