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.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    Responses to combined abiotic and biotic stress in tomato are governed by stress intensity and resistance mechanism
    Kissoudis, Christos ; Sri Sunarti, Sri ; De Wiel, Clemens Van; Visser, Richard G.F. ; Linden, Gerard van der; Bai, Yuling - \ 2016
    Journal of Experimental Botany 67 (2016)17. - ISSN 0022-0957 - p. 5119 - 5132.
    Callose - cell death - ethylene - invertase - R-gene resistance - stress severity

    Stress conditions in agricultural ecosystems can occur at variable intensities. Different resistance mechanisms against abiotic stress and pathogens are deployed by plants. Thus, it is important to examine plant responses to stress combinations under different scenarios. Here, we evaluated the effect of different levels of salt stress ranging from mild to severe (50, 100, and 150mM NaCl) on powdery mildew resistance and overall performance of tomato introgression lines with contrasting levels of partial resistance, as well as near-isogenic lines (NILs) carrying the resistance gene Ol-1 (associated with a slow hypersensitivity response; HR), ol-2 (an mlo mutant associated with papilla formation), and Ol-4 (an R gene associated with a fast HR). Powdery mildew resistance was affected by salt stress in a genotype- and stress intensity-dependent manner. In susceptible and partial resistant lines, increased susceptibility was observed under mild salt stress (50mM) which was accompanied by accelerated cell death-like senescence. In contrast, severe salt stress (150mM) reduced disease symptoms. Na+ and Cl- accumulation in the leaves was linearly related to the decreased pathogen symptoms under severe stress. In contrast, complete resistance mediated by ol-2 and Ol-4 was unaffected under all treatment combinations, and was associated with a decreased growth penalty. Increased susceptibility and senescence under combined stress in NIL-Ol-1 was associated with the induction of ethylene and jasmonic acid pathway genes and the cell wall invertase gene LIN6. These results highlight the significance of stress severity and resistance type on the plant's performance under the combination of abiotic and biotic stress.

    Nauwkeurige gasanalyse-systemen voor kwaliteitsbewaking tijdens fruitopslag : Effecten van ethyleen en ethanol tijdens bewaring van appelen en peren189953 / RAPPORT
    Schaik, A.C.R. van; Reuler, H. van - \ 2015
    Randwijk : Praktijkonderzoek Plant en Omgeving, Bloembollen, Boomkwekerij & Fruit - 39
    fruitteelt - chemische bewaring - bewaarfysiologie - kwaliteitscontroles - kwaliteit na de oogst - houdbaarheid (kwaliteit) - ethyleen - ethanol - appels - peren - proeven op proefstations - sensors - fruit growing - chemical preservation - postharvest physiology - quality controls - postharvest quality - keeping quality - ethylene - ethanol - apples - pears - station tests - sensors
    Met een consortium van bedrijven en kennisinstellingen is onderzoek uitgevoerd naar grenswaarden voor de gasvormige componenten ethyleen en ethanol welke geproduceerd worden voor en tijdens de opslag van hardfruit. De ethyleen productie na de oogst kan mogelijk gebruikt worden als een rijpingsindicator voor partijen of cellen fruit. Deze componenten kunnen zich ook ophopen in de CA (controlled atmosphere) bewaring van appelen en peren en hebben ook tijdens de bewaring ook een duidelijke relatie met de kwaliteit van het product. Tevens is voor ethyleen een prototype ethyleen meter ontwikkeld.
    Met ethyleen heb je de afrijping van tomaten beter in de hand : goed alternatief voor de bespuiting met ethrel
    Stijger, H. ; Janse, J. - \ 2015
    Onder Glas 12 (2015)6/7. - p. 24 - 25.
    glastuinbouw - groenten - tomaten - cultuurmethoden - rijp worden - ethyleen - gewaskwaliteit - teeltsystemen - arbeid (werk) - greenhouse horticulture - vegetables - tomatoes - cultural methods - ripening - ethylene - crop quality - cropping systems - labour
    Het goed afrijpen van de laatste tomaten aan het eind van de teelt is veelal een probleem. Met een gecontroleerde toediening van ethyleengas is het rijpingsproces te bevorderen. Tomatenkwekerij Van Heijningen in Maasdijk heeft hier goede ervaringen mee opgedaan.
    Metabolomics analysis of postharvest ripening heterogeneity of ‘Hass' avocadoes
    Pedreschi, R. ; Munoz, P. ; Robledo, P. ; Becerra, C. ; Defilippi, B.G. ; Eekelen, H.D.L.M. van; Mumm, R. ; Westra, E.H. ; Vos, R.C.H. de - \ 2014
    Postharvest Biology and Technology 92 (2014). - ISSN 0925-5214 - p. 172 - 179.
    mass-spectrometry - persea-americana - fatty-acid - low-oxygen - fruit - metabolite - quality - sugars - maturity - ethylene
    The complex physiology of ‘Hass’ avocado renders its postharvest ripening heterogeneous and unpre-dictable. Several approaches have previously been undertaken to broaden our understanding of the causesof this postharvest ripening heterogeneity but without much success. In this study, a fruit biopsy method-ology was undertaken to sample mesocarp tissue from a series of individual avocado fruit while followingindividual fruit postharvest ripening characteristics without significantly disturbing their metabolism.Using both targeted and untargeted metabolomics approaches, we analyzed the metabolite profiles of thebiopsies in order to get more insight into the biochemical mechanisms underlying ‘Hass’ avocado ripen-ing heterogeneity. While C7sugars (mannoheptulose and perseitol), dry matter and total Ca2+were notcorrelated with time to reach edible ripeness, untargeted metabolomics profiling of polar and semi-polarcompounds (based on GC–MS and LC–MS platforms), revealed several metabolites, mainly amino acids,that were related to ripening heterogeneity. In addition, analysis of fatty acids revealed linoleic acid tobe differentially accumulating. In general, slowest ripening avocados had lower amounts of precursors ofmetabolites involved in key metabolic pathways. Our study indicates that comprehensive metabolomicsmay provide new markers for avocado ripening stage at harvest, and may give more insight into thecomplex ripening physiology of this fruit.
    Opening of Iris flowers is regulated by endogenous auxins
    Doorn, W.G. van; Dole, I. ; Celikel, F.G. ; Harkema, H. - \ 2013
    Journal of Plant Physiology 170 (2013)2. - ISSN 0176-1617 - p. 161 - 164.
    ipomoea-nil convolvulaceae - ethylene - arabidopsis - corolla - growth - acid - gibberellin - elongation - roles
    Flower opening in Iris (Iris x hollandica) requires elongation of the pedicel and ovary. This moves the floral bud upwards, thereby allowing the tepals to move laterally. Flower opening is requires with elongation of the pedicel and ovary. In cv. Blue Magic, we investigated the possible role of hormones other than ethylene in pedicel and ovary elongation and flower opening. Exogenous salicylic acid (SA) and the cytokinins benzyladenine (N6-benzyladenine, BA) and zeatin did not affect opening. Jasmonic acid (JA) and abscisic acid (ABA) were slightly inhibitory, but an inhibitor of ABA synthesis' (norflurazon) was without effect. Flower opening was promoted by gibberellic acid (GA(3)), but two inhibitors of gibberellin synthesis (4-hydroxy-5-isopropyl-2-methylphenyltrimethyl ammonium chloride-l-piperidine carboxylate, AMO-1618; ancymidol) did not change opening. The auxins indoleacetic acid (IAA) and naphthaleneacetic acid (NAA) strongly promoted elongation and opening. An inhibitor of auxin transport (2,3,5-triodobenzoic acid, TIBA) and an inhibitor of auxin effects [alpha-(p-chlorophenoxy)-isobutyric acid; PCIB] inhibited elongation and opening. The data suggest that endogenous auxins are among the regulators of the pedicel and ovary elongation and thus of flower opening in Iris. (C) 2012 Elsevier GmbH. All rights reserved.
    Unraveling Root Developmental Programs Initiated by Beneficial Pseudomonas spp. Bacteria
    Zamioudis, C. ; Mastranesti, P. ; Dhonukshe, P. ; Blilou, I. ; Pieterse, C.M.J. - \ 2013
    Plant Physiology 162 (2013)1. - ISSN 0032-0889 - p. 304 - 318.
    induced systemic resistance - stem-cell niche - arabidopsis-thaliana root - transcription factor myc2 - auxin biosynthesis - rhizosphere microbiome - biocontrol bacteria - promote growth - ethylene - rhizobacteria
    Plant roots are colonized by an immense number of microbes, referred to as the root microbiome. Selected strains of beneficial soil-borne bacteria can protect against abiotic stress and prime the plant immune system against a broad range of pathogens. Pseudomonas spp. rhizobacteria represent one of the most abundant genera of the root microbiome. Here, by employing a germfree experimental system, we demonstrate the ability of selected Pseudomonas spp. strains to promote plant growth and drive developmental plasticity in the roots of Arabidopsis (Arabidopsis thaliana) by inhibiting primary root elongation and promoting lateral root and root hair formation. By studying cell type-specific developmental markers and employing genetic and pharmacological approaches, we demonstrate the crucial role of auxin signaling and transport in rhizobacteria-stimulated changes in the root system architecture of Arabidopsis. We further show that Pseudomonas spp.-elicited alterations in root morphology and rhizobacteria-mediated systemic immunity are mediated by distinct signaling pathways. This study sheds new light on the ability of soil-borne beneficial bacteria to interfere with postembryonic root developmental programs.
    Canopy light cues affect emission of constitutive and methyl jasmonate-induced volatile organic compounds in Arabidopsis thaliana
    Kegge, W. ; Weldegergis, B.T. ; Soler, R. ; Vergeer-van Eijk, M.H. ; Dicke, M. ; Voesenek, L.A.C.J. ; Pierik, R. - \ 2013
    New Phytologist 200 (2013)3. - ISSN 0028-646X - p. 861 - 874.
    salicylic-acid - host-plant - induced resistance - insect herbivores - indirect defenses - chemical ecology - shade avoidance - abiotic factors - bean-plants - ethylene
    The effects of plant competition for light on the emission of plant volatile organic compounds (VOCs) were studied by investigating how different light qualities that occur in dense vegetation affect the emission of constitutive and methyl-jasmonate-induced VOCs. Arabidopsis thaliana Columbia (Col-0) plants and Pieris brassicae caterpillars were used as a biological system to study the effects of light quality manipulations on VOC emissions and attraction of herbivores. VOCs were analysed using gas chromatography-mass spectrometry and the effects of light quality, notably the red : far red light ratio (R : FR), on expression of genes associated with VOC production were studied using reverse transcriptase-quantitative PCR. The emissions of both constitutive and methyl-jasmonate-induced green leaf volatiles and terpenoids were partially suppressed under low R : FR and severe shading conditions. Accordingly, the VOC-based preference of neonates of the specialist lepidopteran herbivore P. brassicae was significantly affected by the R : FR ratio. We conclude that VOC-mediated interactions among plants and between plants and organisms at higher trophic levels probably depend on light alterations caused by nearby vegetation. Studies on plant-plant and plant-insect interactions through VOCs should take into account the light quality within dense stands when extrapolating to natural and agricultural field conditions.
    Ethyleenproductie- en gevoeligheid van diverse soorten vruchtbomen tijdens gesimuleerde bewaar- en transportomstandigheden
    Schaik, A.C.R. van; Elk, P.J.H. van; Anbergen, R.H.N. - \ 2013
    Randwijk : Praktijkonderzoek Plant en Omgeving, Bloembollen, Boomkwekerij & Fruit - 18
    vruchtbomen - rassen (planten) - cultivars - gevoeligheid van variëteiten - koudeopslag - opslag met klimaatbeheersing - ethyleen - schade - landbouwkundig onderzoek - fruit trees - varieties - cultivars - varietal susceptibility - cold storage - controlled atmosphere stores - ethylene - damage - agricultural research
    Vruchtbomen zijn tijdens bewaring en transport gevoelig voor ethyleengas dat bv geproduceerd wordt door verbrandingsmotoren en rijpend fruit. In het recente onderzoek uitgevoerd door PPO Fruit is ook vastgesteld dat ook de vruchtbomen zelf enigermate ethyleen produceren. Daarom is er extra noodzaak om de koelcellen goed te ventileren met buitenlucht en de bewaartemperatuur van de bomen zo laag mogelijk te houden. Vastgesteld is dat de schadegrens van vruchtbomen op ongeveer 0.5 ppm ligt, waarbij de perenbomen het gevoeligste zijn. Ook is vastgesteld dat ethyleenschade kan optreden tijdens het transport van vruchtbomen bij hogere temperaturen. Binnen enkele dagen kan dat al tot schade leiden.
    Carbon dioxide and ethylene gas in the potato storage atmosphere and their combined effect on processing colour
    Daniels-Lake, B.J. - \ 2013
    Wageningen University. Promotor(en): Paul Struik; R.K. Prange. - S.l. : s.n. - ISBN 9789461736376 - 169
    solanum tuberosum - aardappelen - opslag - gasbewaring - ethyleen - kooldioxide - bewaarfysiologie - behandeling na de oogst - solanum tuberosum - potatoes - storage - controlled atmosphere storage - ethylene - carbon dioxide - postharvest physiology - postharvest treatment

    Keywords: Solanum tuberosum L., carbon dioxide, ethylene, storage, processing, fry colour, chip colour, 1-methylcyclopropene

    The finished colour of processed potato (Solanum tuberosum L.) products is a very important quality characteristic which is attributable to the concentration of reducing sugars in the raw tubers. Many internal and external factors can affect the concentration of these sugars during long-term storage. Ethylene gas, produced by the tubers or from external sources such as pathogens or engine exhaust, is known to increase reducing sugars and darken processing colour. For many years, elevated CO2 from tuber respiration or external sources was also believed to affect sugars and cause darkening, although the research was somewhat contradictory. Restricted ventilation in potato storage buildings can cause appreciable accumulation of both gases in the storage atmosphere.

    The effects of elevated CO2 and depleted O2, with and without trace ethylene (0.5 µL L-1), in the atmosphere surrounding potatoes were investigated. Short-term studies (three or nine weeks) using cultivar Russet Burbank stored at 9 ºC were conducted during several consecutive storage terms, with evaluation of the processing colour at intervals of three weeks. No responses to elevated CO2 or depleted O2 were observed, whereas ethylene darkened colour slightly. However, the colour was darker when tubers were exposed to CO2 and ethylene together than with ethylene alone. At 0, 0.5, 1.0 and 2.0% CO2 with 0, 0.25 and 0.5 µL L-1 ethylene in a 4 × 3 factorial design, the colour darkened as the concentration of either gas increased, except in CO2 without ethylene where darkening was not observed. Pre-treatment with the ethylene blocking compound, 1-methylcyclopropene prevented darkening attributable to 0.5 µL L-1 ethylene and to 2% CO2 plus 0.5 µL L-1 ethylene.

    Long-term studies (December to June) using cultivars Shepody, Innovator and Dakota Pearl in addition to Russet Burbank were subsequently undertaken, using 2% CO2 with 0.5 or 10 µL L-1 ethylene (trace and sprout-inhibiting concentrations, respectively) and evaluations every four weeks. There was little or no change in processing colour in Dakota Pearl, a potato chip cultivar, in response to any of the treatments throughout the storage season. In the three French fry cultivars Russet Burbank, Innovator and Shepody, processing colour was darker in response to either concentration of ethylene at four weeks after the exposure began, although recovery to a lighter colour occurred with increased duration of storage in Russet Burbank and Shepody tubers. Interestingly, darkening in response to 2% CO2 applied alone was observed after exposure for eight weeks or more in all three French fry cultivars. Darkening attributable to CO2 and ethylene applied together was observed from the first evaluation after the start of exposure in the three French fry cultivars. This darkening occurred whether or not the cultivar responded to ethylene or CO2 alone, and was worse than with ethylene alone in all three cultivars, except that Shepody tubers exposed to CO2 plus 10 µL L-1 ethylene was the same as with 10 µL L-1 ethylene alone. The magnitude of darkening varied slightly among cultivars, and was usually more severe as storage duration increased.

    This research has provided useful information to help storage managers maintain the physiological condition of stored potato tubers to ensure light processing colour.

    Verslag proeven Chinese kool bewaring 2012 - 2013 : verslag van N-bemestingsproef, CA-bewaring in hoezen en ethyleenmetingen
    Wijk, C.A.P. van; Wilms, J.A.M. - \ 2013
    Lelystad : PPO AGV (PPO publicatie 558) - 42
    opslag - houdbaarheid (kwaliteit) - chinese koolsoorten - stikstof - bemesting - ethyleen - opslagkwaliteit - meting - bladgroenten - vollegrondsgroenten - storage - keeping quality - chinese cabbages - nitrogen - fertilizer application - ethylene - storage quality - measurement - leafy vegetables - field vegetables
    Chinese kooltelers willen graag productverlies bij Chinese kool uit bewaring beperken en de bewaarperiode verlengen tot eind maart. Het merendeel van de partijen wordt nu in januari/februari geruimd. Het grootste verlies wordt veroorzaakt door het wegschonen van de 1-2 extra buitenbladen die voor bewaarkool mee geoogst worden, door vochtverlies tijdens de bewaring en door rot. Na een literatuur- en praktijkkennisinventarisatie is door de telers in 2012 gekozen voor de volgende onderzoeksonderwerpen ter verbeteringen van de bewaring van Chinese kool: a) N-bemestingswijzen, planttijdstippen en plantsapanalyses, b) Controlled Atmosphere (CA)-bewaring in hoezen en c) praktijktoetsing van ethyleengehalten in bewaarcellen.
    Productkwaliteit : State-of-the-art bewaren van tulpenbollen (2)
    Wildschut, J. - \ 2013
    BloembollenVisie 2013 (2013)271. - ISSN 1571-5558 - p. 22 - 22.
    bloembollen - tulpen - opslag met klimaatbeheersing - ventilatie - ethyleen - controle - projecten - ornamental bulbs - tulips - controlled atmosphere stores - ventilation - ethylene - control - projects
    Het in 2007 gestarte project State-of-the-Art bewaren van tulpenbollen heeft laten zien dat met deze technologie veel energie bespaard kan worden. De kwaliteit van de bollen wordt hierbij verbeterd. Daarnaast is er tot en met 2011 veel aanvullend onderzoek verricht, onder meer naar de verbetering van de luchtverdeling over de kistenstapeling. Hierdoor kan nog veel meer energie bespaard worden. In een reeks van vier artikelen worden de bevindingen van dit project samengevat. Dit tweede artikel behandelt de productkwaliteit.
    Effects of rind removal on physicochemical quality characteristics of fresh-cut watermelon [Citrus lanatus (Thunb) Matsum & Nakai] during cold storage
    Petrou, P. ; Soteriou, G. ; Schouten, R.E. ; Kyriacou, C. - \ 2013
    International Journal of Food Science and Technology 48 (2013)2. - ISSN 0950-5423 - p. 357 - 362.
    lycopene stability - shelf-life - fruit - ethylene
    The impact of removing the rind from fresh-cut watermelon slices was assessed on the quality of the product during storage at 4 °C for 9 days. Flesh lycopene declined from 55.4 to 47.9 mg kg-1 f.w. and colour lightness (L*) increased from 43.2 to 45.8 after 2 days of storage. Initial heart and placental flesh firmness increased from 7.3 and 9.8 N, respectively, to 9.5 and 12.8 N after 9 days, but were unaffected by rind processing. Electrolyte leakage from placental tissue was unaffected by storage and rind. Rind presence limited juice run-off by 47.2% and maintained mean total soluble sugar concentration in the slices at 86.0 mg mL-1 as opposed to 76.8 mg mL-1 in rind-less slices. Change in the quality was most pronounced between 0 and 2 day of storage. Removing the rind accelerated senescence and off-flavour production, while the presence of rind improved the overall storage stability of fresh-cut watermelon slices.
    ABA-deficiency results in reduced plant and fruit size in tomato
    Nitsch, L. ; Kohlen, W. ; Oplaat, C. ; Charnikhova, T. ; Cristescu, S. ; Michieli, P. ; Wolters-Arts, M. ; Bouwmeester, H.J. ; Mariani, C. ; Vriezen, W.H. ; Rieu, I. - \ 2012
    Journal of Plant Physiology 169 (2012)9. - ISSN 0176-1617 - p. 878 - 883.
    abscisic-acid biosynthesis - shoot growth - arabidopsis-thaliana - endogenous aba - ethylene - mutants - drought - stress - gene - expression
    Abscisic acid (ABA) deficient mutants, such as notabilis and flacca, have helped elucidating the role of ABA during plant development and stress responses in tomato (Solanum lycopersicum L.). However, these mutants have only moderately decreased ABA levels. Here we report on plant and fruit development in the more strongly ABA-deficient notabilis/flacca (not/flc) double mutant. We observed that plant growth, leaf-surface area, drought-induced wilting and ABA-related gene expression in the different genotypes were strongly correlated with the ABA levels and thus most strongly affected in the not/flc double mutants. These mutants also had reduced fruit size that was caused by an overall smaller cell size. Lower ABA levels in fruits did not correlate with changes in auxin levels, but were accompanied by higher ethylene evolution rates. This suggests that in a wild-type background ABA stimulates cell enlargement during tomato fruit growth via a negative effect on ethylene synthesis.
    Vermijd ethyleen in bomencellen : ethyleenschade bij bewaring fruitbomen: feiten en maatregelen : onderzoek
    Schaik, A.C.R. van - \ 2012
    De Fruitteelt 102 (2012)47. - ISSN 0016-2302 - p. 18 - 19.
    vruchtbomen - koudeopslag - ethyleen - schade - maatregelen - agrarische bedrijfsvoering - fruit trees - cold storage - ethylene - damage - measures - farm management
    Af en toe komt het voor dat er ethyleenschade optreedt bij de bewaring van fruitbomen. Tegenwoordig worden er steeds meer fruitbomen bewaard om tijdig te kunnen leveren en eventueel vorstschade te voorkomen. Alex van Schaik, onderzoeker WUR, behandelt in dit artikel onder welke omstandigheden ethyleenschade zich kan manifesteren, welke boomsoorten en rassen gevoelig zijn, de mogelijke ethyleenbronnen en hoe fruitboomkwekers en fruittelers schade kunnen voorkomen.
    Kernrot in tulp : de effecten van cultivar, ethyleeen, bollenmijten en stromijten
    Lommen, S.T.E. ; Duyvestein, R. ; Breeuwsma, S.J. ; Boer, F.A. de; Haaster, A.J.M. van; Leijden, J.P.H. van; Gude, H. - \ 2012
    Lisse : Praktijkonderzoek Plant & Omgeving BBF - 45
    tulpen - bollen - mijten - rhizoglyphus - tyrophagus - rassen (planten) - cultivars - ethyleen - landbouwkundig onderzoek - tulips - bulbs - mites - rhizoglyphus - tyrophagus - varieties - cultivars - ethylene - agricultural research
    Kernrot is het (gedeeltelijk) wegrotten van de spruit binnenin de tulpenbol. Deze schade is aan de buitenkant van de bol niet zichtbaar, waardoor ogenschijnlijk gezonde bollen na planten geen of een misvormde bloem geven. Het is nooit opgehelderd welke mijten precies kernrot veroorzaken: bollenmijten (waarmee in dit geval mijten van het geslacht Rhizoglyphus worden bedoeld), stromijten (mijten van het geslacht Tyrophagus) of beide. In dit project werd de rol van bollen- en stromijten in het ontstaan van kernrot onderzocht. Hiervoor werden verschillende cultivars gebruikt (4 parkiettulpen en 3 andere typen) die aan verschillende omstandigheden blootgesteld werden.
    Moderate abiotic stresses increase rhizome growth and outgrowth of axillary buds in Alstroemeria cultured in vitro
    Pumisutapon, P. ; Visser, R.G.F. ; Klerk, G.J. De - \ 2012
    Plant Cell, Tissue and Organ Culture: an international journal on in vitro culture of higher plants 110 (2012)3. - ISSN 0167-6857 - p. 395 - 400.
    dormancy development - salicylic-acid - abscisic-acid - plants - ethylene - morphology - heat - thermotolerance - protection - responses
    Alstroemeria is multiplied in vitro by forced outgrowth of lateral rhizomes from rhizome explants. The multiplication rate is very low because of strong apical dominance and poor rhizome growth. We report here that moderate abiotic stresses stimulate both rhizome growth and outgrowth of lateral rhizomes, and accordingly increase multiplication. Rhizome explants were exposed to heat by a hot-water treatment (HWT) or by a hot-air treatment. Both increased rhizome growth when applied for 1 or 2 h in the range of 30–40 C. The maximal enhancement was 75 %. Other abiotic stresses were also examined. Cold (0 C) and partial anaerobiosis increased rhizome growth significantly. The increases brought about by drought and salinity were not statistically significant. Because underground storage tissues like rhizomes are adaptations to survive climatic stresses, we presume that the increased sink-strength of rhizomes induced by moderate stress is related to stress adaptation. Moderate heat stress (38 C HWT, 1 h) also resulted in protection of Alstroemeria plantlets from severe heat stress (45 C HWT, 1–2 h) a few hours after the moderate stress. All abiotic stresses also increased the outgrowth of lateral rhizomes.
    OSCILLATOR: A system for analysis of diurnal leaf growth using infrared photography combined with wavelet transformation
    Bours, R.M.E.H. ; Muthuraman, M. ; Bouwmeester, H.J. ; Krol, A.R. van der - \ 2012
    Plant Methods 8 (2012). - ISSN 1746-4811
    arabidopsis-thaliana - circadian clock - ethylene - plant - movement - mutants - rhythms - angle
    Background Quantification of leaf movement is an important tool for characterising the effects of environmental signals and the circadian clock on plant development. Analysis of leaf movement is currently restricted by the attachment of sensors to the plant or dependent upon visible light for time-lapse photography. The study of leaf growth movement rhythms in mature plants under biological relevant conditions, e.g. diurnal light and dark conditions, is therefore problematic. Results Here we present OSCILLATOR, an affordable system for the analysis of rhythmic leaf growth movement in mature plants. The system contains three modules: (1) Infrared time-lapse imaging of growing mature plants (2) measurement of projected distances between leaf tip and plant apex (leaf tip tracking growth-curves) and (3) extraction of phase, period and amplitude of leaf growth oscillations using wavelet analysis. A proof-of-principle is provided by characterising parameters of rhythmic leaf growth movement of different Arabidopsis thaliana accessions as well as of Petunia hybrida and Solanum lycopersicum plants under diurnal conditions. The amplitude of leaf oscillations correlated to published data on leaf angles, while amplitude and leaf length did not correlate, suggesting a distinct leaf growth profile for each accession. Arabidopsis mutant accession Landsberg erecta displayed a late phase (timing of peak oscillation) compared to other accessions and this trait appears unrelated to the ERECTA locus. Conclusions OSCILLATOR is a low cost and easy to implement system that can accurately and reproducibly quantify rhythmic growth of mature plants for different species under diurnal light/dark cycling.
    DCS en ethyleen verminderen schilvlekjes
    Schoorl, F.W. ; Schaik, A.C.R. van - \ 2012
    De Fruitteelt 102 (2012)38. - ISSN 0016-2302 - p. 6 - 7.
    appels - opslag met klimaatbeheersing - ethyleen - rijp worden - landbouwkundig onderzoek - opslagkwaliteit - houdbaarheid (kwaliteit) - apples - controlled atmosphere stores - ethylene - ripening - agricultural research - storage quality - keeping quality
    Bewaring onder DCS-condities van Elstar vermindert het optreden van schilvlekjes in Elstar. Een experiment bij PPO Fruit te Randwijk toonde in 2011/`12 het positieve effect aan van DCS™ op het terugdringen van schilvlekjes. Dit was niet nieuw, maar werd niet eerder zo sterk vastgesteld als in dit experiment. Ook zagen we een goed resultaat van toegediend ethyleen bij bewaring onder ULO-condities. Onder ULO trad wél enig hardheid- en kleurverlies op bij continue toediening van ethyleen.
    Flower Life: ontwikkeling duurzame bloembehandelingstechnologieën
    Woltering, E.J. ; Harkema, H. - \ 2012
    Wageningen UR Food & Biobased Research : Wageningen UR - Food & Biobased Research (Rapport / Wageningen UR Food & Biobased Research nr. 1340) - ISBN 9789461733382 - 57
    sierplanten - snijbloemen - snijbloemconserveringsmiddelen - vaasleven - ethyleen - landbouwkundig onderzoek - ornamental plants - cut flowers - cut flower preservatives - vase life - ethylene - agricultural research
    Adequate behandeling van snijbloemen ter voorkoming van ethyleeneffecten, vatverstopping en blad(vergelings)problemen is een noodzaak bij langdurige bewaring en transport. De middelen die hiervoor beschikbaar zijn worden toegepast als voorbehandeling, transportbehandeling of nabehandeling. Een aantal van deze middelen bevat stoffen die vanuit duurzaamheidsoogpunt minder wenselijk zijn, zoals (zware) metalen. Binnen dit project is gezocht naar natuurlijke of natuuridentieke verbindingen met geen of minder milieubezwaren om een aantal van de bovengenoemde fysisch/fysiologische defecten te behandelen. Hierbij zijn we uitgegaan van bestaande verbindingen met al een gedocumenteerd effect op bv. bacteriegroei of ethyleensynthese, dit effect hoeft niet niet per se in snijbloemen te zijn aangetoond. Hiernaast is als belangrijk duurzaamheidscriterium vooral gekeken of de betreffende stof vermeld wordt op lijsten van bv. “toegestane middelen in biologische productie methode”, “verbindingen met GRAS status” of “toegestane additieven in voedingsmiddelen (E-nummers)”. Er zijn na literatuuronderzoek zo’n 150 verbindingen geselecteerd waarvan er na overleg met o.a. de onderzoeksbegeleidingscommissie (OBC) zo’n 60 op de shortlist zijn gekomen. Hiervan zijn er ongeveer 40 getest op snijbloemen (anjer, roos, lelie). Naast laboratorium experimenten zijn er met een beperkt aantal middelen en/of combinaties testen onder praktijkomstandigheden gedaan. De anti ethyleen verbindingen die zowel wat betreft werkzaamheid als vanuit milieuoogpunt goed scoorden zijn amino ethoxy vinylglycine (AVG, Retain) en, in mindere mate 1-MCP. Een aantal andere middelen met positief effect op bloemkwaliteit (boorzuur, 2,4 pyridine dicarboxylaat [PDCA]) vertoonden onacceptabele bladschade. De anti bacteriële middelen die goed scoorden zijn EDTA en, in mindere mate poly aspartic acid (PAA) en lysozyme. Het onderzoek biedt diverse aanknopingspunten voor verdere ontwikkeling en formulering van deze middelen.
    Plant neighbor detection through touching leaf tips precedes phytochrome signals
    Wit, M. de; Kegge, W. ; Evers, J.B. ; Vergeer-van Eijk, M.H. ; Gankema, P. ; Voesenek, L.A.C.J. ; Pierik, R. - \ 2012
    Proceedings of the National Academy of Sciences of the United States of America 109 (2012)36. - ISSN 0027-8424 - p. 14705 - 14710.
    arabidopsis-thaliana - shade avoidance - petiole elongation - light quality - growth - responses - ethylene - gene - tobacco - perception
    Plants in dense vegetation compete for resources, including light, and optimize their growth based on neighbor detection cues. The best studied of such behaviors is the shade-avoidance syndrome that positions leaves in optimally lit zones of a vegetation. Although proximate vegetation is known to be sensed through a reduced ratio between red and far-red light, we show here through computational modeling and manipulative experiments that leaves of the rosette species Arabidopsis thaliana first need to move upward to generate sufficient light reflection potential for subsequent occurrence and perception of a reduced red to far-red ratio. This early hyponastic leaf growth response is not induced by known neighbor detection cues under both climate chamber and natural sunlight conditions, and we identify a unique way for plants to detect future competitors through touching of leaf tips. This signal occurs before light signals and appears to be the earliest means of above-ground plant–plant signaling in horizontally growing rosette plants.
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