Swelling of cell walls in mature sweet cherry fruit : factors and mechanisms

Main conclusion: Swelling of sweet cherry cell walls is a physical process counterbalanced by turgor. Cell turgor prevents swelling in intact cells, whereas loss of turgor allows cell walls to swell. Abstract: Swelling of epidermal cell walls precedes skin failure in sweet cherry (Prunus avium) cracking. Swollen cell walls lead to diminished cell:cell adhesions. We identify the mechanism of cell wall swelling. Swelling was quantified microscopically on epidermal sections following freeze/thaw treatment or by determining swelling pressure or swelling capacity of cell wall extracts. Releasing turgor by a freeze/thaw treatment increased cell wall thickness 1.6-fold within 2 h. Pressurizing cell wall extracts at > 12 kPa prevented swelling in water, while releasing the pressure increased swelling. The effect was fully reversible. Across cultivars, cell wall thickness before and after turgor release in two subsequent seasons was significantly correlated (before release of turgor: r = 0.71**, n = 14; after release of turgor: r = 0.73**, n = 14) as was the swelling of cell walls upon turgor release (r = 0.71**, n = 14). Close relationships were also identified for cell wall thickness of fruit of the same cultivars grown in the greenhouse and the field (before release of turgor: r = 0.60, n = 10; after release of turgor: r = 0.78**, n = 10). Release of turgor by heating, plasmolysis, incubation in solvents or surfactants resulted in similar swelling (range 2.0–3.1 µm). Cell wall swelling increased from 1.4 to 3.0 µm as pH increased from pH 2.0 to 5.0 but remained nearly constant between pH 5.0 and 8.0. Increasing ethanol concentration decreased swelling. Swelling of sweet cherry cell walls is a physical process counterbalanced by turgor. © 2020, The Author(s)

Calcium decreases cell wall swelling in sweet cherry fruit

Swelling of epidermal cell walls decreases cell-to-cell adhesion and increases cracking susceptibility in sweet cherry. Ca is suggested to decrease cracking susceptibility by crosslinking of cell wall components and, possibly, by decreasing swelling. The objective is to test this hypothesis. The effect of Ca on swelling of anticlinal epidermal cell walls was quantified microscopically in vivo using excised skin sections and in vitro using extracted cell walls. After removal of turgor, cell wall thickness increased. Incubation in CaCl2 decreased cell wall thickness up to 3 mM CaCl2. At higher concentrations thickness remained constant. Decreased cell wall swelling in vivo also occurred with other salts of divalent and trivalent cations, but not with those of monovalent cations. Decreased swelling was due to the Ca cation, the anions had no effect. Ca also decreased swelling of cell walls that were already swollen. CaCl2 also decreased swelling of extracted cell walls in vitro. There was no effect on swelling pressure. The effect on swelling increased as the CaCl2 concentration increased. Chlorides of divalent and trivalent cations, but not those of monovalent cations decreased swelling in vitro. The decrease in swelling among the divalent cations was linearly related to the radius of the cation. The results indicate that Ca decreases cracking susceptibility by decreasing swelling

Dialogische Prozesse in der Instrumentalpädagogik

Die Fragestellung des vorliegenden Forschungsprojektes lautet: Welche Qualitäten der pädagogischen Beziehung lassen sich ausgehend vom Phänomen der Begegnung (M.Buber) über einen subjektorientierten Zugang zu einem Forschungsfeld im Verlauf musikalischer Lernprozesse hinsichtlich spezifisch instrumentalpädagogischer Anforderungen beobachten und in für die pädagogische Praxis geeigneten sprachlichen Begriffen differenziert beschreiben? (DIPF/Orig.

Eine "virtuelle Insel für Qual-Frösche": Erfahrungsbericht einer netzbasierten qualitativen Arbeitsgruppe im Rahmen des NetzWerkstatt-Konzepts

In this article an account is given of the net-based working processes among the members of a group of qualitative researchers, called "Leuchtfeuer" (NetzWerkstatt, Institute for Qualitative Research, Freie Universität Berlin, see http://www.qualitative-forschung.de/netzwerkstatt/arbeitsgruppen/gruppen/NW4/). After presenting the group and the contexts of group development, three main characteristics constitutive for the group's profile will be outlined using the metaphors of: "island life," as extracted before from data analysis (Section 5.1); "'voluntariness in joining or leaving, in taking and giving back" (Section 5.1.1); "specifics in the phase of life of candidates doing their doctorate" (Section 5.1.2); "confining and protective mechanisms adapted by the 'islanders' during their voluntary insulation in a 'virtual island world'" (Section 5.1.3). Section 5.2 addresses the question in what respect does "island life" meets specific requirements of qualitative research: exploratory phases of qualitative research need expert colloquy in "periods of rough copy and draft" (Section 5.2.1). This can be explained by attributes like "spontaneity" (Section 5.2.2) and "'fluidity" (Section 5.2.3) of successive utterances; both dispositions of mutual support by informational expert interchange emerge from "island life." This situation of enhanced communicative activities among experts will on the one hand stimulate productive thinking and abductive reasoning. Along with extensive activities (Section 5.2.4), each researcher is summoned to develop capacities of reflection and selection in respect to one's own subject matter. From our point of view, the general conditions of the NetzWerkstatt concept—particularly aspects of "protection" and "continuity"—constitute a potentially serviceable and commonsense definition of the field of communication. However, the range of possibilities opened by permanent and quasi-automatic documentation of communicative research work—in our context referred to as everyday activities in the form of correspondence among group members' synchronous written communication (chat) and asynchronous digital correspondence (mailing list)—have not yet been adequately recognized. URN: urn:nbn:de:0114-fqs090134En este artículo se da cuenta de los procesos de trabajo basados en la red, entre los miembros de un grupo de investigadores cualitativos llamado "Faro" (Red de Trabajo, Instituto para la Investigación Cualitativa, Universidad Libre de Berlín, véase http://www.qualitative-forschung.de/netzwerkstatt/arbeitsgruppen/gruppen/NW4/). Luego de presentar el grupo y los contextos en los que el grupo se desenvuelve, se delinearán tres principales características constitutivas del perfil del grupo, utilizando metáforas de: "vida insular", como fue extraída antes del análisis de datos (sección 5.1); "voluntad de unirse o irse, de tomar o devolver" (sección 5.1.1); "especificidades en la fase de vida de candidatos haciendo su doctorado" (sección 5.1.2); "confinamiento y mecanismos de protección adaptados por los ‘isleños’ durante su aislamiento voluntario en un ‘mundo virtual insular’" (sección 5.1.3) La sección 5.2 apunta a la pregunta acerca de en qué sentido la "vida insular" encuentra requerimientos específicos en la investigación cualitativa: fases exploratorias de la investigación cualitativa requieren de un coloquio especializado en los "períodos del primer borrador" (sección 5.2.1). Esto puede ser explicado por atributos como "espontaneidad" (sección 5.2.2) y "fluidez" (sección 5.2.3) de sucesivas palabras; ambas disposiciones de soporte mutuo emergen de la "vida insular" por el intercambio experto informacional. Esta situación de actividades comunicativas mejoradas entre expertos estimulará el pensamiento productivo y el razonamiento abductivo. Junto con actividades extensas (sección 5.2.4), cada investigador es convocado a desarrollar capacidades de reflexión y selección en relación con su propio tema. Desde nuestro punto de vista, las condiciones generales del concepto de "trabajo en red" – particularmente los aspectos de "protección" y "continuidad" – constituyen una definición potencialmente duradera y de sentido común del campo de la comunicación. Sin embargo, el rango de posibilidades abiertas por la permanente y casi automática documentación de trabajo de investigación comunicativo – en nuestro contexto referido a las actividades cotidianas en la forma de correspondencia entre los escritos sincronizados de los miembros del grupo (Chat) y la correspondencia digital asincrónica (lista de correo) – no han sido aún reconocido adecuadamente. URN: urn:nbn:de:0114-fqs090134In diesem Beitrag werden die Arbeitsprozesse der netzbasierten qualitativen Arbeitsgruppe "Leuchtfeuer" (NetzWerkstatt-Konzept, Institut für Qualitative Forschung, Internationale Akademie an der Freien Universität Berlin) aus lernender Perspektive ins Blickfeld genommen. Nach der Vorstellung der Arbeitsgruppe und deren Rahmenbedingungen (Abschnitt 1 bis 4) werden auf der Basis in der Gruppe erhobener qualitativer Daten und entlang einer im Gruppenprozess explorierten Metapher, der des "Insellebens" (Abschnitt 5.1.), drei wesentliche Eigenschaften der Gruppe zusammengefasst: "Freiwilligkeit im Kommen und Gehen und Geben und Nehmen" (Abschnitt 5.1.1), "Spezifik der Lebensphase Promovierender" (Abschnitt 5.1.2) und "Abgrenzungs- und Schutzmechanismen der virtuellen Inselwelt" (Abschnitt 5.1.3). Der Frage, inwieweit das "Inselleben" den spezifischen Erfordernissen eines qualitativen Forschungsstiles gerecht wird, widmet sich Textabschnitt 5.2: Die explorativen Phasen qualitativen Forschens erfordern fachlichen Austausch in Bereichen des "Entwurfhaften und Vorläufigen" (Abschnitt 5.2.1), welches durch die in der "Inselwelt" erworbene Bereitschaft zu "Spontaneität" (Abschnitt 5.2.2) und "Fluidität" (Abschnitt 5.2.3) der Kommunikationshandlungen expliziert werden kann. Diese Situation einer erhöhten Kommunikationsaktivität von Promovierenden regt auf der einen Seite produktive Kognitionen und abduktive Denkprozesse an, auf der anderen Seite werden innerhalb eines langwierigen "Denk-, Auseinandersetzungs- und Produktionsprozesses" (Abschnitt 5.2.4) (selbst-) reflexive und selektive Fähigkeiten der Forschenden hinsichtlich der eigenen Forschungsthematik erforderlich. Die Rahmenbedingungen des NetzWerkstatt-Konzepts – insbesondere Schutz und Kontinuität der Gruppe – konstatieren demnach aus Perspektive der Teilnehmenden ein im virtuellen Raum potenziell funktionsfähiges und lebensweltlich abgrenzbares Kommunikationsfeld. Die Möglichkeiten, die über die permanente und quasi-automatische Fixierung der als Gegenwartshandlung zu bezeichnenden schriftsprachlichen Kommunikationshandlungen der Arbeitsgruppe hinsichtlich wissenschaftlicher Reflexions- und Produktionsprozesse eröffnet werden, wurden in den entsprechenden Fachdiskursen bisher noch nicht ausreichend wahrgenommen. URN: urn:nbn:de:0114-fqs09013

Mediators and Cytokines in Persistent Allergic Rhinitis and Nonallergic Rhinitis with Eosinophilia Syndrome

Background: Patients with nonallergic rhinitis with eosinophilia syndrome (NARES) show typical symptoms of persistent allergic rhinitis (PAR). The aim of the present study was to compare nasal cytokine patterns between NARES and PAR. Methods: Nasal secretions of 31 patients suffering from NARES, 20 patients with PAR to house dust mite and 21 healthy controls were collected using the cotton wool method and analyzed for interleukin (IL)-1 beta, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, IL-10, IL-12, IL-13, IL-17, granulocyte-macrophage colony-stimulating factor (GM-CSF), granulocyte colony-stimulating factor (G-CSF), interferon-gamma (IFN-gamma), tumor necrosis factor-alpha (TNF-alpha), monocyte chemoattractant protein-1 (MCP-1) and macrophage inflammatory protein-1 beta (MIP-1 beta) by Bio-Plex Cytokine Assay as well as eosinophil cationic protein (ECP) and tryptase by UniCAP-FEIA. Results: NARES and PAR presented elevated levels of tryptase, while ECP was markedly increased solely in NARES compared to both the controls and PAR. Elevated levels of IL-1 beta, IL-17, IFN-gamma, TNF-alpha and MCP-1 were found in NARES compared to the controls as well as PAR. MIP-1 beta was elevated in NARES and PAR, while IL-4, IL-6 and G-CSF showed increased levels in NARES, and IL-5 was elevated in PAR only. Conclusions: In patients with NARES and PAR, eosinophils and mast cells appear to be the pivotal cells of inflammation, reflected by high levels of tryptase and ECP as well as IL-5 and GM-CSF as factors for eosinophil migration and survival. The elevated levels of proinflammatory cytokines in NARES may indicate the chronic, self-perpetuating process of inflammation in NARES which seems to be more pronounced than in PAR. IL-17 might be a factor for neutrophilic infiltration or be responsible for remodeling processes in NARES. Copyright (C) 2012 S. Karger AG, Base

Diversification for sustainable and resilient agricultural landscape systems

This virtual issue comprises papers that address diversification for providing sustainable solutions at different scales from cropping and grassland to food systems. The authors investigated processes in case studies at the landscape scale where synergies and trade-offs between social and environmental objectives become the most tangible. Contributions from all continents highlighted regional specificities related to diversification and include research from natural and social sciences, with inter- and transdisciplinary approaches including synthesis of knowledge (reviews), empirical studies with experiments as well as assessments with interviews in case studies: Model-based design of crop diversification, the role of digitalization for achieving sustainability in the European context, ecological engineering for rice pest suppression in China, the role of cereal species mixtures in Ethiopian smallholder farmers, diversified planting in arid irrigation areas in northwestern China, integration of legumes in European and Canadian cropping systems, screening of native forage legumes for northern Swedish grassland systems, cropping system diversification of smallholder farmers in south-central Bangladesh, identification of how farmers imagine diversified landscapes in southern Idaho in the US, farm diversification affecting impacts from COVID-19 across Europe, the role of diversified farming in Mato Grosso Brazil, diversification and soil management measures in Germany, value chain formation for the scaling of crop diversification, and the design process with farmers and scientists for the transition toward legume-supported farming in Europe. A key finding from these examples is that agricultural intensification has led to the simplification of cropping systems and landscapes in terms of species diversity and ecosystem function. To instead move towards sustainable transformation, all system levels (i.e. from the plot, farm, landscape, governance and overall food systems) need to interact and reinforce each other for diversification to deliver the desired outcomes

Efficacy of different strategies using an ALS-inhibitor herbicide for weed control in sugar beet (Beta vulgaris L.)

In den Jahren 2013 und 2014 wurden in sechs Umwelten in Deutschland Feldversuche durchgeführt, um die Wirksamkeit eines neuen ALS-Inhibitor Herbizids (F/T) zur Unkrautkontrolle im Zuckerrübenanbau zu bewerten. Fünf Herbizidstrategien mit verschiedenen Anwendungen von F/T (50 g Foramsulfuron ha–1 + 30 g Thiencarbazone-methyl ha–1) und eine klassische Herbizidstrategie mit drei Applikationen von Phenmedipham (75 g Wirkstoff ha–1), Desmedipham (59 g Wirkstoff ha–1), Ethofumesat (94 g Wirkstoff ha–1), Lenacil (34 g Wirkstoff ha–1) und Metamitron (700 g Wirkstoff ha–1) wurden miteinander verglichen. Die Wirksamkeit der klassischen Herbizidstrategie lag zwischen 84 und 99% durch nicht voll­ständig kontrollierte Chenopodium album L., Matricaria recutita L., Mercurialis annua L. und Solanum tuberosum L. Die durchschnittliche Wirksamkeit von F/T lag bei 95% in der einmaligen Applikation. Strategien mit zwei Applikationen in Kombination von klassischen Herbiziden und F/T erreichten eine Wirksamkeit über 97%. Dies führt zu einer höheren Flexibilität der Unkrautkontrolle in Zuckerrüben.In 2013 and 2014, field trials were conducted at six environments in Germany to evaluate the efficacy of a new ALS-inhibiting herbicide containing foramsulfuron and thiencarbazone-methyl (F/T) for weed control in sugar beet cultivation. Five herbicide strategies with different application frequencies of F/T (50 g foramsulfuron ha–1 + 30 g thiencarbazone-methyl ha–1) and a classic herbicide strategy with three applications of phenmedipham (75 g ai ha–1), desmedipham (59 g ai ha–1), ethofumesate (94 g ai ha–1), lenacil (34 g ai ha–1) and metamitron (700 g ai ha–1) were compared. The efficacy of the classic herbicide strategy was between 84 and 99% due to surviving Chenopodium album L., Matricaria recutita L., Mercurialis annua L. and Solanum tuberosum L. Average efficacy of F/T was 95% in the single application treatment. Strategies with two applications combining classic herbicides and F/T achieved an efficacy beyond 97%. This points to an increased flexibility of weed control in sugar beet

Crack initiation and propagation in sweet cherry skin: A simple chain reaction causes the crack to ‘run’

Rain cracking severely affects the commercial production of many fleshy-fruit species, including of sweet cherries. The objectives were to investigate how the gaping macroscopic cracks (macrocracks) of a rain-cracked fruit can develop from microscopic cracks in the cuticle (microcracks). Incubating fruit in deionized water is well known to cause significant macrocracking. We found that after a lag phase of 2 h, the numbers and lengths of macrocracks increased. Macrocrack number approached an asymptote at 12 h, whereas macrocrack length continued to increase. The rate of macrocrack propagation (extension at the crack tip) was initially 10.8 mm h-1 but then decreased to a near-constant 0.5 mm h-1. Light microscopy revealed three characteristic zones along a developing macrocrack. In zone I (ahead of the crack), the cuticle was intact, the epidermal cells were unbroken and their cell walls were thin. In zone II, the cuticle was fractured, the first epidermal cells died and their cell walls began to thicken (swell). In zone III, most epidermal cells had died, their cell walls were swollen and cell:cell separation began along the middle lamellae. The thickness of the anticlinal epidermal cell walls and the percentage of intact living cells along a crack were closely and negatively related. Cracks were stained by calcofluor white, but there was no binding of monoclonal antibodies (mAbs) specific for hemicelluloses (LM11, LM21, LM25). Strong binding was obtained with the anti-homogalacturonan mAb (LM19), indicating the presence of unesterified homogalacturonans on the crack surface. We conclude that macrocrack propagation is related to cell death and to cell wall swelling. Cell wall swelling weakens the cell:cell adhesion between neighbouring epidermal cells, which separate along their middle lamellae. The skin macrocrack propagates like a ‘run’ in a fine, knitted fabric