Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

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The sound of salts by Broadband Acoustic Resonance Dissolution Spectroscopy
Ruth, Saskia van; Dekker, Pieter ; Brouwer, Erwin ; Rozijn, Maikel ; Erasmus, Sara ; Fitzpatrick, Dara - \ 2018
Food Research International (2018). - ISSN 0963-9969 - 12 p.
Authenticity - BARDS - Food identity - Provenance - Resonance - Sound spectroscopy

Salts are available in different grades and in a wide price range. Some contain more impurities than others, while some have special culinary traits that determine their identity. Acoustic profiling, which is based on the ‘hot chocolate effect’ may provide an interesting strategy to characterise salts of various origins to underpin their identity. In this study, the link between the identity of 60 food grade and technical salts and their acoustic properties was examined by Broad Acoustic Resonance Dissolution Spectroscopy. In particular, the influence of the composition of the salts and the impact of the salts’ particle size distributions on their acoustic profiles were examined. Sodium and potassium contents were measured by flame photometry and the salts’ particle size distributions by laser light diffraction. Reference salts (NaCl, KCl, MgCl2) and mixtures thereof were analysed for comparison, as well as intact and ground versions of the salt samples. The results show that both the composition and morphology of the salt crystals determine the down-slope of the resonance frequency, which is caused by the rate of release of entrained and dissolved gas. Coarse salts with high levels of non-NaCl constituents showed a rapid decline in sound frequency, which corresponds to a high gas release rate. On the other hand fine salts composed of pure NaCl revealed a slower change in sound frequency and thus lower gas release rates. The frequency minimums were however not affected by the salts’ compositions nor particle size distributions. It is primarily the particle size distribution that affects the rate at which gas is released, and thus the change in sound frequency. Only when the particles are more similar in size, the composition also starts playing a role. Since both particle size distribution and composition is unique for each salt, the various salts show distinct acoustic profiles. Evidently, the current study shows that ‘listening’ to the sound of salts reveals interesting information about their identity and origin.

Classification of European and Mediterranean coastal dune vegetation
Marcenò, Corrado ; Guarino, Riccardo ; Loidi, Javier ; Herrera, Mercedes ; Isermann, Maike ; Knollová, Ilona ; Tichý, Lubomír ; Tzonev, Rossen T. ; Acosta, Alicia Teresa Rosario ; Fitzpatrick, Úna ; Iakushenko, Dmytro ; Janssen, John A.M. ; Jiménez-Alfaro, Borja ; Kacki, Zygmunt ; Keizer-Sedláková, Iva ; Kolomiychuk, Vitaliy ; Rodwell, John S. ; Schaminée, Joop H.J. ; Šilc, Urban ; Chytrý, Milan - \ 2018
Applied Vegetation Science 21 (2018)3. - ISSN 1402-2001 - p. 533 - 559.
Ammophiletea - Biogeography - Expert system - Honckenyo-Elymetea - Koelerio-Corynephoretea canescentis - Phytosociology - Sand dune - Vegetation classification

Aims: Although many phytosociological studies have provided detailed local and regional descriptions of coastal dune vegetation, a unified classification of this vegetation in Europe and the Mediterranean Basin has been missing. Our aim is to produce a formalized classification of this vegetation and to identify the main factors driving its plant species composition at a continental scale. Location: Atlantic and Baltic coasts of Europe, Mediterranean Basin and the Black Sea region. Methods: We compiled a database of 30,759 plots of coastal vegetation, which were resampled to reduce unbalanced sampling effort, obtaining a data set of 11,769 plots. We classified these plots with TWINSPAN, interpreted the resulting clusters and used them for developing formal definitions of phytosociological alliances of coastal dune vegetation, which were included in an expert system for automatic vegetation classification. We related the alliances to climatic factors and described their biogeographic features and their position in the coastal vegetation zonation. We examined and visualized the floristic relationships among these alliances by means of DCA ordination. Results: We defined 18 alliances of coastal dune vegetation, including the newly described Centaureo cuneifoliae-Verbascion pinnatifidi from the Aegean region. The main factors underlying the differentiation of these alliances were biogeographic and macroclimatic contrasts between the Atlantic-Baltic, Mediterranean and Black Sea regions, along with ecological differences between shifting and stable dunes. The main difference in species composition was between the Atlantic-Baltic and Mediterranean-Black Sea regions. Within the former region, the main difference was driven by the different ecological conditions between shifting and stable dunes, whereas within the latter, the main difference was biogeographic between the Mediterranean and the Black Sea. Conclusions: The first formal classification of the European coastal dune vegetation was established, accompanied by an expert system containing the formal definitions of alliances, which can be applied to new data sets. The new classification system critically revised the previous concepts and integrated them into a consistent framework, which reflects the main gradients in species composition driven by biogeographic influences, macroclimate and the position of the sites in the coast-inland zonation of the dune systems. A revision of the class concept used in EuroVegChecklist is also proposed.

Formalized classification of European fen vegetation at the alliance level
Peterka, Tomáš ; Hájek, Michal ; Jiroušek, Martin ; Jiménez-Alfaro, Borja ; Aunina, Liene ; Bergamini, Ariel ; Dítě, Daniel ; Felbaba-Klushyna, Ljuba ; Graf, Ulrich ; Hájková, Petra ; Hettenbergerová, Eva ; Ivchenko, Tatiana G. ; Jansen, Florian ; Koroleva, Natalia E. ; Lapshina, Elena D. ; Lazarević, Predrag M. ; Moen, Asbjørn ; Napreenko, Maxim G. ; Pawlikowski, Paweł ; Plesková, Zuzana ; Sekulová, Lucia ; Smagin, Viktor A. ; Tahvanainen, Teemu ; Thiele, Annett ; Biţǎ-Nicolae, Claudia ; Biurrun, Idoia ; Brisse, Henry ; Ćušterevska, Renata ; Bie, Els De; Ewald, Jörg ; FitzPatrick, Úna ; Font, Xavier ; Jandt, Ute ; Kącki, Zygmunt ; Kuzemko, Anna ; Landucci, Flavia ; Moeslund, Jesper E. ; Pérez-Haase, Aaron ; Rašomavičius, Valerijus ; Rodwell, John S. ; Schaminée, Joop H.J. ; Šilc, Urban ; Stančić, Zvjezdana ; Chytrý, Milan ; Schwabe-Kratochwil, Angelika - \ 2017
Applied Vegetation Science 20 (2017)1. - ISSN 1402-2001 - p. 124 - 142.
Biogeography - Ecological gradients - Endangered habitats - Mires - Relevés - Supervised vegetation classification - Unsupervised vegetation classification - Vegetation plots - Wetlands
Aims: Phytosociological classification of fen vegetation (Scheuchzerio palustris-Caricetea fuscae class) differs among European countries. Here we propose a unified vegetation classification of European fens at the alliance level, provide unequivocal assignment rules for individual vegetation plots, identify diagnostic species of fen alliances, and map their distribution. Location: Europe, western Siberia and SE Greenland. Methods: 29 049 vegetation-plot records of fens were selected from databases using a list of specialist fen species. Formal definitions of alliances were created using the presence, absence and abundance of Cocktail-based species groups and indicator species. DCA visualized the similarities among the alliances in an ordination space. The ISOPAM classification algorithm was applied to regional subsets with homogeneous plot size to check whether the classification based on formal definitions matches the results of unsupervised classifications. Results: The following alliances were defined: Caricion viridulo-trinervis (sub-halophytic Atlantic dune-slack fens), Caricion davallianae (temperate calcareous fens), Caricion atrofusco-saxatilis (arcto-alpine calcareous fens), Stygio-Caricion limosae (boreal topogenic brown-moss fens), Sphagno warnstorfii-Tomentypnion nitentis (Sphagnum-brown-moss rich fens), Saxifrago-Tomentypnion (continental to boreo-continental nitrogen-limited brown-moss rich fens), Narthecion scardici (alpine fens with Balkan endemics), Caricion stantis (arctic brown-moss rich fens), Anagallido tenellae-Juncion bulbosi (Ibero-Atlantic moderately rich fens), Drepanocladion exannulati (arcto-boreal-alpine non-calcareous fens), Caricion fuscae (temperate moderately rich fens), Sphagno-Caricion canescentis (poor fens) and Scheuchzerion palustris (dystrophic hollows). The main variation in the species composition of European fens reflected site chemistry (pH, mineral richness) and sorted the plots from calcareous and extremely rich fens, through rich and moderately rich fens, to poor fens and dystrophic hollows. ISOPAM classified regional subsets according to this gradient, supporting the ecological meaningfulness of this classification concept on both the regional and continental scale. Geographic/macroclimatic variation was reflected in the second most important gradient. Conclusions: The pan-European classification of fen vegetation was proposed and supported by the data for the first time. Formal definitions developed here allow consistent and unequivocal assignment of individual vegetation plots to fen alliances at the continental scale.
A new 1D biogeochemical model framework for assessing and managing acid sulfate soil risks
Mosley, L.M. ; Fitzpatrick, R. ; Bonten, L.T.C. ; Groenenberg, J.E. - \ 2012
In: Proceedings of the 7th International Acid Sulfate Soil Conference in Vaasa, 28 August - 01 September 2012, Vaasa, Finland. - Finland : Espoo - p. 72 - 74.
Candidate genes for behavioural ecology
Fitzpatrick, M.J. ; Ben-Sahar, Y. ; Smid, H.M. ; Vet, L.E.M. ; Robinson, G.E. ; Sokolowski, M.B. - \ 2005
Trends in Ecology and Evolution 20 (2005)2. - ISSN 0169-5347 - p. 96 - 104.
dependent protein-kinase - alternative reproductive tactics - silkmoth antheraea-pernyi - horn length dimorphism - drosophila-melanogaster - philomachus-pugnax - onthophagus-taurus - learning-ability - hormonal-control - monogamous vole
In spite of millions of years of evolutionary divergence, the conservation of gene function is common across distant lineages. As such, genes that are known to influence behaviour in one organism are likely to influence similar behaviours in other organisms. Recent studies of the evolution of behaviour and morphological adaptation support this notion. Thus, the candidate gene approach offers great potential to expand our understanding of behavioural ecology. Changes in the expression of candidate genes can reveal their contribution to behavioural variation and/or phenotypic plasticity. Knowledge of gene function also enables experimental manipulation of behaviour in the lab and in the field. The candidate gene approach provides an accessible and useful tool for generating insights about animals that are not typically associated with genetic experimentation
Monitoring/detectie van Pythium in tomaat
Paternotte, S.J. ; Groen, B.W. - \ 2004
PPO Glastuinbouw (Rapporten PPO Glastuinbouw ) - 22
solanum lycopersicum - tomaten - pythium - plantenziekteverwekkende schimmels - monitoring - detectie - nederland - glastuinbouw - gewasbescherming - tomatoes - plant pathogenic fungi - detection - netherlands - greenhouse horticulture - plant protection
Op bedrijven worden regelmatig tomatenplanten gevonden die zonder aanwijsbare redenen slap gaan en /of vaatverbruining hebben. Verticillium, pepinomozaïekvirus en Pythium en alle combinaties van deze pathogenen lijken hierbij een rol te kunnen spelen. Daarom zijn een aantal bedrijven waar deze verschijnselen voorkwamen over een periode van drie teeltseizoenen inclusief de teeltwisselingen gemonitord. Op de bedrijven zijn in wortels van tomatenplanten Pythium diclinum Tokunga, Pythium sp. “group F (alleen filamenteuze sporangia) en Pythium aphanidermatum (Edson) Fitzpatrick gevonden. De verspreiding van Pythium op deze bedrijven was zeer grillig en het optreden van Pythium-aantasting onvoorspelbaar. Het lijkt er wel op dat de kans op Pythium-aantasting het grootst is na een periode van zeer zware plantbelasting, een periode van donker of extreem warm weer, na geven van erg koud water, een erg droog of nat teeltsubstraat en/of als latere symptomen van pepinomozaïekvirus worden waargenomen. Er wordt daarom geadviseerd op een flink aantal plaatsen vroegtijdig wortelmonsters te nemen, te laten onderzoeken op de aanwezigheid van Pythium en als Pythium is gevonden een behandeling met chemische gewasbeschermingsmiddelen uit te voeren op het moment dat aantasting kan worden verwacht. Nog beter is uiteraard om aantasting te voorkomen door het geven van erg koud water en een erg droog of nat teeltsubstraat te vermijden. Er is geen relatie tussen het watergehalte van de matten, de aanwezigheid van Pythium in de wortels en zichtbare Pythium-aantasting in de vorm van wortelrot gevonden. Alle isolaten waren gevoelig voor zowel Previcur N als AAterra , maar het meest gevoelig voor AAterra.
Restricting layers, flow paths, and correlation between duration of soil saturation and soil morphological features along a hillslope with an altered soil water regime in western Victoria
Brouwer, J. ; Fitzpatrick, R.W. - \ 2002
Australian Journal of Soil Research 40 (2002)6. - ISSN 0004-9573 - p. 927 - 946.
quantitative relationships - degraded landscapes - dundas tableland - dryland salinity - color patterns - indiana soils - australia - terrain - groundwater - catchments
This paper is the second of two describing how soil macromorphological and chemical data can be combined with soil hydrological data to distinguish between, and to quantify, past and present hydrological processes relevant to waterlogging and dryland salinity. The first paper provides a methodological framework for the study, and describes the initial interpretation of the macromorphological features of the toposequence studied, using the soil feature-system-domain grouping method. This second paper deals with the added value of extensive piezometric and other hydrological observations relative to soil macromorphological studies, and with quantitative relationships between soil colour and duration of waterlogging. As with the first paper, this paper focuses on a soil toposequence at Gatum on the eastern Dundas Tableland in western Victoria. For the the broad crest with yellow gradational soils or Dermosols (Plinthoxeralfs), the hydrological data confirmed the conclusion from macromorphological observations that: (1) There are three levels at which downward flow of water is restricted: at the top of the largely unaltered mottled zone, that is at 0.8-1.0 m depth, well below the top of the yellow Bt1-horizon (fresh water); at the top of the pallid zone, at about 3-3.5 m depth (fresh water); and on top of the unweathered ignimbrite (saline water). (2) Below about 30 mm depth, down at least as far as 2.0 m and sometimes even more, the major pathways for downward movement of water are indeed root channels, with or without live roots, and not interpedal cracks. The 3-dimensional spacing of the rootholes above and through the less-permeable mottled zone, and the (horizontal) conductivity, storage capacity, and thickness of overlying horizons determine the extent of ponding, runoff, and deep infiltration taking place. In addition, the hydrological observations showed that: (3) If rainfall is regular, well-spaced, and not excessive, ponding is unlikely to take place even where there is a rainfall surplus and there are layers restricting downward flow of water. Furthermore, along the toposequence with yellow duplex soils or Dermosols, Chromosols, and Hydrosols, (4) There were generally good correlations between duration of saturation at the bottom of the E-horizon and colour aspects of the E-horizon (value and chroma of the matrix) and of the B2-horizon (hue, value, and chroma of the matrix). Based on these findings additional suggestions are made for improving identification and management of water logging and salinisation processes
Interpretation of morphological features in a salt-affected duplex soil toposequence with an altered soil water regime in western Victoria
Brouwer, J. ; Fitzpatrick, R.W. - \ 2002
Australian Journal of Soil Research 40 (2002)6. - ISSN 0004-9573 - p. 903 - 926.
degraded landscapes - dundas tableland - australia - salinity - ancient - hillslope - duration
This paper is the first of two describing how soil macromorphological and chemical data can be combined with a minimum of hydrological data to distinguish between, and to quantify, past and present hydrological processes. These processes are relevant to both waterlogging and dryland salinity. The purpose of this first paper is to establish a methodological framework. It also describes the initial interpretation of the macromorphological features of the toposequence studied at Gatum on the Dundas Tablelands in western Victoria. A modified version of the soil feature¿system¿domain grouping method was used. Macromorphological data combined with only limited piezometric data showed that: (1) The soil feature¿system¿domain grouping method makes it possible to distinguish between the effects of past and present hydrological processes on soil macromorphology at Gatum. (2) Waterlogging of the surface horizons at Gatum is often caused by perching of soil water within the B-horizon (as opposed to on top of the B-horizon). Changes in soil structure and in colour of cutans and mottles can be an indicator of this first restricting layer. (3) It is likely that interpedal cracks and old tree root holes act as preferred paths for water to flow through this first restricting layer. (4) A second fresh perched water table can occur on top of the pallid zone. Where the pallid zone reaches close to the surface the two perched water tables may merge and cause a local increase in waterlogging, as indicated by local soil morphology. When this occurs, hillside seeps can occur quite high up on the slopes, even when there is no apparent irregularity in surface topography. 5) The permanent saline water table occurs on top of the bedrock and causes salting problems where it comes too close to the soil surface. Salting problems at the bottom of a slope are more severe where fresh perched water tables increase waterlogging On the basis of these findings the suitability of various management options to reduce waterlogging and salinisation is discussed. Further findings regarding restricting layers, flow paths through the soils, and relations between duration of saturation and soil morphological features, are discussed in a companion paper (by J. Brouwer and R. W. Fitzpatrick, pp. 927-946 in this issue).
Relations between soil macro-morphology and current soil hydrology in a toposequence in SE Australia
Brouwer, J. ; Fitzpatrick, R.W. - \ 1998
In: Symposium 15, Proceedings 16th World Congress of Soil Science, Montpellier, 1998, International Society of Soil Science, Vienna, and Association Française pour l'Etude du Sol, Ardon, France, CD-Rom, 7 pp
Glycoalkaloids and phenolic compounds in gamma irradiated potatoes; a food irradiation study on radiation induced stress in vegetable products
Bergers, W.W.A. - \ 1980
Landbouwhogeschool Wageningen. Promotor(en): W. Pilnik, co-promotor(en): J.H. Koeman. - Wageningen : Bergers - 49
voedingsmiddelen - voedselbewaring - druk - fermentatie - solanum tuberosum - aardappelen - straling - effecten - deeltjes - bestraling - ioniserende straling - landbouw - glycoalkaloïden - foods - food preservation - pressure - fermentation - potatoes - radiation - effects - particles - irradiation - ionizing radiation - agriculture - glycoalkaloids
Irradiation is a recent preservation method. With the aid of ionizing radiation microorganisms in food can be killed or specific physiological processes in vegetable products can be influenced.<p/>In order to study the effects of metabolic radiation stress on quantitative chemical changes in vegetable products, specific target compounds were investigated in stored irradiated potatoes. These target compounds, i.e. glycoalkaloids and phenolic compounds were choosen with a view to food toxicology and food sensoric quality.<p/>Much attention has been spent on quantitative analyses of the pre-selected target compounds in the potato samples. Enzymic changes of the polyphenolic compounds were kept to a minimum by the direct freezing of potato slices in liquid nitrogen, freeze-drying and extraction by boiling in 80% ethanol.<p/>A quantitative assay for solanidine potato glycoalkaloids was developed from a pre-existing method with minor changes, by which the rapidity of the assay is improved, without affecting its sensitivity. As a specific application, this method was used for the analysis of solanidine glycoalkaloids in industrial potato protein. Because of objections to the colour assays for glycoalkaloids, concerning their specificity (Fitzpatrick & Osman, 1974; Coxon et al., 1979), these quantitative reactions were investigated.<p/>Quantitative analyses of phenolics and coumarins were done, starting from the alcoholic extracts. Qualitative data were obtained by analysis of UV spectra and fluorescence of diluted extracts and TLC chromatography on cellulose plates. For quantitative analyses a method was developed by HPLC chromatography of alcoholic extracts. Evidence with respect to identification of scopolin and scopoletin in the alcoholic extracts was obtained by comparison of extracts with and without enzymic hydrolysis with B-glycosidase. Scopoletin was also directly identified by UV, IR and Mass Spectra.<p/>Results of glycoalkaloids, analyzed over several seasons, show no significant changes with regard to irradiation dose or storage time. On the other hand a change in phenolic compounds and coumarins was observed.<p/>A 10 to 30 fold accumulation of scopolin was found in irradiated (3 kGy) potatoes of the Eba variety after approx. one month's storage at 10 °C, 90% RH and also a decrease in the chlorogenic acid content. For irradiated (3 kGy) potatoes of the Bintje variety, the increase in fluorescent compounds was smaller. Several unidentified phenolic compounds increase in 3 kGy irradiated Eba potatoes, which were detected by UV absorbance at 310 nm.<p/>Chemical analyses of samples of irradiated Eba potatoes indicate a dose threshold for accumulation of fluorescent compounds. Below 0.5 kGy no increase is observed.<p/>By using the high fluorescence of the accumulated coumarins it was possible to detect accumulation of fluorescent compounds by simply examining potato halves under long wave UV light. The results agree with the chemical analyses of extracts of irradiated potatoes of the Eba and Bintje varieties. In this way potatoes of several varieties irradiated with a dose of 3 kGy and stored for at least 2 weeks at 10 °C could be examined. The results indicate pronounced differences between varieties. Further, a <em>threshold</em> for the accumulation of fluorescent compounds in irradiated Eba potatoes could be determined. In Eba potatoes irradiated above 0.5 kGy accumulation of fluorescent compounds could be seen. By fluorescence microscopy of sections of tubers it was observed that specific cells accumulate fluorescent coumarins. Examination of the fluorescent cells after plasmolysis, indicates a vacuolar origin of these compounds. Similar results have been reported for fungal infected potatoes (Clarke, 1973; Clarke & Baines, 1976). The increase in scopoletin can be explained by the increase in phenyl ammonia lyase, which has been shown to increase in irradiated citrus fruits (Riov et al., 1972) and irradiated potatoes (Pendharkar & Nair, 1975).<p/>In view of conflicting earlier reports of increases in mutagenic compounds in alcoholic extracts of irradited potatoes, glycoalkaloids and phenolic compounds as well as the alcoholic extracts of irradiated and control potatoes were examined using a bacterial mutagenicity test system. No increased mutagenicity of extracts or reference compounds were found. These results aqree with the negative findings of Levinsky & Wilson (1975) for mutagenic evaluation of extracts of irradiated potatoes and mutagenicity studies on irradiated potatoes and chlorogenic acid by Hossain et al. (1976).<p/>Radiation-induced increase in coumarins is to be expected primarily in vegetable products having a natural coumarin content. Chemical changes as a result of radiolytic processes in a theoretical foodstuff can be estimated. Diehl & Schertz (1975) calculated 55 mg/kg radiolytic decomposition products for a 5 kGy dose. In comparison, in this study an increase in scopolin content from 2 to 60 mg/kg was found in 3 kGy irradiated Eba potatoes after a month's storage at 10 °C caused by metabolic stress.
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