Staff Publications

Staff Publications

  • external user (warningwarning)
  • Log in as
  • language uk
  • About

    '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.

    We have a manual that explains all the features 

    Records 1 - 20 / 182

    • help
    • print

      Print search results

    • export

      Export search results

    Check title to add to marked list
    Elimination of epidermal wax from explants increases growth in tissue culture of lily
    Askari, Naser ; Klerk, Geert Jan De - \ 2020
    Scientia Horticulturae 274 (2020). - ISSN 0304-4238
    Contamination - Epidermis - Lily - Scale - Uptake - Wax

    The aerial parts of plants are covered by the cuticle, a skin containing among others waxes. The cuticle inhibits the outflow of compounds, in particular water, from the plant to the environment, and without a cuticle, plants dehydrate rapidly. In the cuticle, waxes are the chief actors in the blocking. In tissue culture, the humidity in the headspace is very high (close to 100 %) so evaporation is limited and the cuticle is less needed. The cuticle also inhibits the entry of compounds from the environment into plants. In tissue culture, the inflow of medium components occurs predominantly via wounds, primarily those made when explants are cut. The removal of the barrier is expected to enhance the uptake of medium components. This paper addresses the question as to whether the removal of the epidermal inflow barrier enhances growth in tissue culture of lily. Waxes were removed from scale explants by a short rinse (5 s) with chloroform. During this rinse, the stomata had to be closed since otherwise the tissue was severely damaged by the inflow of chloroform into the cavities below the stomata. The closure was achieved by an abscisic acid (ABA) pre-treatment. Removal of wax resulted in increased growth (50 %) relative to nonchloroform-treated explants. This procedure is, however, not suitable for practical application because the benefit was undone by an inhibitory effect of the ABA pre-treatment. The ABA pre-treatment also increased the percentage of contaminated cultures, probably because during surface-sterilization the disinfectant did not reach the contaminants inhabiting the cavities below the stomata when the stomata had been closed.

    Assessing the activity of individual group-housed broilers throughout life using a passive radio frequency identification system—a validation study
    Sluis, Malou van der; Haas, Yvette de; Klerk, Britt de; Rodenburg, T.B. ; Ellen, Esther D. - \ 2020
    Sensors 20 (2020)13. - ISSN 1424-8220 - p. 1 - 21.
    Activity - Broilers - Radio frequency identification - Tracking - Ultra-wideband - Video

    Individual data are valuable for assessing the health, welfare and performance of broilers. In particular, data on the first few days of life are needed to study the predictive value of traits recorded early in life for later life performance. However, broilers are generally kept in groups, which hampers individual identification and monitoring of animals. Sensor technologies may aid in identifying and monitoring individual animals. In this study, a passive radio frequency identification (RFID) system was implemented to record broiler activity, in combination with traditional video recordings. The two main objectives were 1) to validate the output of the RFID system by comparing it to the recorded locations on video, and 2) to assess whether the number of antennas visited per unit time could serve as a measure of activity, by comparing it to the distance recorded on video and to the distance moved as recorded using a validated ultra-wideband (UWB) tracking system. The locations recorded by the RFID system exactly matched the video in 62.5% of the cases, and in 99.2% of the cases when allowing for a deviation of one antenna grid cell. There were moderately strong Spearman rank correlations between the distance recorded with the RFID system and the distance recorded from video (rs = 0.82) and between UWB and RFID (rs = 0.70) in approximately one-hour recordings, indicating that the RFID system can adequately track relative individual broiler activity, i.e., the activity level of a broiler in comparison to its group members. As the RFID tags are small and lightweight, the RFID system is well suited for monitoring the individual activity of group-housed broilers throughout life.

    Effect of novel branching regulators on micropropagation of zantedeschia sprengeri (paco)
    Shahin, Heba ; Klerk, G.J. De - \ 2020
    Egyptian Journal of Botany 60 (2020)1. - ISSN 0375-9237 - p. 1 - 7.
    Apical dominance - Fluridone - Imazalil - Strigolactone - Zantedechia

    THE NOVEL branching regulators fluridone and imazalil (IMA) were examined for micropropagation of Paco (Zantedeschia sprengeri). IMA concentrations were 0, 4.5, 13.5 and 45µM in combination with 5µM benzylaminopurine (BAP). The shoots were transferred after 8 weeks to standard MS medium without IMA but with 5µM BAP. IMA resulted in a strong increase of new shoots from which the outgrowth was inhibited when IMA was present but that did grow out when IMA had been removed. Fluridone inhibits the biosynthesis of the endogenous regulator strigolactone. Increasing concentrations of fluridone were applied in combination with 13.5µM IMA for 8 weeks. Then the shoots were subcultured on standard medium without IMA and fluridone but with 5µM BAP for 8 weeks. Again a strong increase of new shoots occurred from which outgrowth was inhibited when IMA and fluridone were present but that did grow out when these regulators had been removed.

    On-farm automated tracking of group-housed poultry
    Ellen, E.D. ; Sluis, M. van der; Klerk, B. de; Haas, Y. de; Hijink, Thijme ; Rodenburg, T.B. - \ 2019
    In: Book of abstracts of the 70th Annual Meeting of the European Federation of Animal Science (EAAP). - Wageningen Academic Publishers (Book of Abstracts ) - ISBN 9789086863396 - p. 136 - 136.
    Production animals, including poultry, are increasingly kept in groups, making identication and tracking of individual animals challenging. Often video analyses are used, but these are time-consuming and prone to human error. Therefore, automated systems for monitoring individual animals are desired. One possible approach is the implementation of an ultra-wideband (UWB) system to track individual animals. A previous study implemented an UWB system for laying hens in a research setting. Hens were tted with an UWB tag in a small backpack and, using stationary sensing beacons, the location of each bird could be determined. Compared to video tracking of individual birds, the UWB system was shown to be capable of detecting the bird’s location with 85% accuracy. In the current study, the system was applied on a broiler farm to assess its on-farm applicability. At approximately 14 days of age, broilers were tted with an UWB tag. Twelve birds were tracked with the UWB system on nineteen consecutive days, for one hour each day. Distances moved according to the UWB system were compared to those found on video and a moderately strong correlation between the UWB system and video tracking was found (Repeated measures correlation, r=0.71, P<0.0005). Furthermore, individual levels of activity were assessed using this setup. 137 birds from different genetic crosses were tracked near-continuously for seventeen consecutive days. First results indicate that for all crosses, the UWB system was found to be capable of detecting a decrease in activity over time. Overall, the UWB system appears well-suited for tracking of broilers. However, the UWB tags are relatively large. Therefore, tracking and monitoring of young broilers is not possible. Current work is focussing on implementing a passive radio frequency identication system, with smaller tags. Possibly, this system can track individual activity of broiler chickens throughout their life.
    Potential of DNA pooling for the inclusion of commercial slaughterhouse data in genetic improvement
    Aldridge, M.N. ; Klerk, B. de; Haas, Y. de; Greef, K.H. de - \ 2019
    In: Book of Abstracts of the 70th Annual Meeting of the European Federation of Animal Science. - Wageningen Academic Publishers (EAAP Book of Abstracts 25) - p. 289 - 289.
    Pregnant women's adherence to national food-based dietary guidelines in the Netherlands, as assessed using the DHD15-index
    Beulen, Y.H. ; Klerk, de, E. ; Wagemakers, A. ; Vries, J.H.M. - \ 2019
    Developing sensor technologies to inform breeding approaches to reduce damaging behaviour in laying hens and pigs: The GroupHouseNet approach
    Rodenburg, T.B. ; Bennewitz, J. ; Haas, E.N. De; Košťál, L. ; Pichová, K. ; Piette, D. ; Tetens, J. ; Visser, B. ; Klerk, B. De; Sluis, Malou van der; Zande, L.E. van der; Siegford, J. ; Toscano, M. ; Norton, T. ; Guzhva, O. ; Ellen, E.D. - \ 2019
    In: Precision Livestock Farming 2019. - Teagasc (Precision Livestock Farming 2019 - Papers Presented at the 9th European Conference on Precision Livestock Farming, ECPLF 2019 ) - ISBN 9781841706542 - p. 467 - 470.
    Automatic tracking - Damaging behaviour - Genetic selection

    The European COST Action GroupHouseNet aims to provide synergy for preventing damaging behaviour in group-housed pigs and laying hens. One area of focus of this network is how genetic and genomic tools can be used to breed animals that are less likely to develop damaging behaviour directed at their pen-mates. Reducing damaging behaviour in large groups is a challenge, because it is difficult to identify and monitor individual animals. With the current developments in sensor technologies and animal breeding, there is the possibility to identify individual animals, monitor individual behaviour, and link this information to the genotype. Using a combination of sensor technologies and genomics enables us to select against damaging behaviour in pigs and laying hens.

    Assessing individual activity levels in two broiler lines using an ultra-wideband tracking system
    Sluis, Malou van der; Klerk, B. De; Ellen, E.D. ; Haas, Y. De; Hijink, T. ; Rodenburg, T.B. - \ 2019
    In: Precision Livestock Farming 2019. - Teagasc (Precision Livestock Farming 2019 - Papers Presented at the 9th European Conference on Precision Livestock Farming, ECPLF 2019 ) - ISBN 9781841706542 - p. 903 - 906.
    Activity - Broilers - Tracking - Ultra-wideband

    Individual data on activity of broilers is valuable for breeding programmes, as activity may serve as proxy for multiple health, welfare and performance indicators. However, in current husbandry systems, broilers are often kept in large groups, which makes it difficult to identify and monitor them at the individual level. Sensor technologies, such as ultra-wideband (UWB) tracking systems, might offer solutions. This paper investigated the recorded distances of an UWB tracking system that was applied to broilers, as a first step in assessing the potential of an UWB tracking system for studying individual levels of activity in broilers housed in groups. To this end, the distances moved as recorded by the UWB system were compared to distances recorded on video, using Kinovea video tracking software. There was a moderately strong positive correlation between the output of the UWB system and video tracking, although some under- and over- estimations were observed. Even though the recorded distances from the UWB system may not completely match the true distances moved, the UWB system appears to be well-suited for studying differences in activity between individual broilers when measured with the same system settings.

    Validation of an ultra-wideband tracking system for recording individual levels of activity in broilers
    Sluis, Malou Van Der; Klerk, Britt De; Ellen, Esther D. ; Haas, Yvette De; Hijink, Thijme ; Rodenburg, Bas - \ 2019
    Animals 9 (2019)8. - ISSN 2076-2615
    Activity - Broilers - Group housing - Tracking - Ultra-wideband

    Broiler chickens are often kept in large groups, which makes it difficult to identify individual birds and monitor their activity. Here, we studied whether an automated tracking system, using ultra-wideband technology, could be implemented to study activity of individual broilers. We compared the distance as recorded with the tracking system to the distance recorded on video and found a moderately strong positive correlation. Using the tracking system, we were able to detect decreases in activity over time, and we found that lightweight birds were on average more active than heavier birds. Both these results match with reports from literature and therefore support the conclusion that the tracking system appears well-suited for monitoring activity in broilers. The information on activity over time that can be collected with this system can potentially be used to study health, welfare and performance at the individual level, but further research into individual patterns in activity is required. Individual data on activity of broilers is valuable, as activity may serve as a proxy for multiple health, welfare and performance indicators. However, broilers are often kept in large groups, which makes it dificult to identify and monitor them individually. Sensor technologies might offer solutions. Here, an ultra-wideband (UWB) tracking system was implemented with the goal of validating this system for individual tracking of activity of group-housed broilers. The implemented approaches were (1) a comparison of distances moved as recorded by the UWB system and on video and (2) a study recording individual levels of activity of broilers and assessing group-level trends in activity over time; that could be compared to activity trends from literature. There was a moderately strong positive correlation between the UWB system and video tracking. Using the UWB system, we detected reductions in activity over time and we found that lightweight birds were on average more active than heavier birds. Both findings match with reports in literature. Overall, the UWB system appears well-suited for activity monitoring in broilers, when the settings are kept the same for all individuals. The longitudinal information on differences in activity can potentially be used as proxy for health, welfare and performance; but further research into individual patterns in activity is required.

    Automated tracking of individual activity of broiler chickens
    Sluis, M. van der; Klerk, B. de; Rodenburg, T.B. ; Haas, Y. de; Hijink, Thijme ; Ellen, E.D. - \ 2019
    In: Proceedings of the 53rd Congress of the International Society for Applied Ethology (ISAE). - Wageningen, The Netherlands : Wageningen Academic Publishers - ISBN 9789086863389 - p. 288 - 288.
    There is a growing interest in quantifying individual behaviour of group-housed animalsand its relation to individual performance. Broiler chickens are an example of a livestockspecies for which individual data can be valuable. Broiler breeding goals focus on efficientgrowth and reproduction, as well as welfare indicators for balanced genetic improvements.Recording of broiler behaviour can provide insight into welfare indicators, such as activity orgeneral leg health. However, monitoring individual behaviour in group-housed animals is achallenge. Often, video analyses are used, but these are time-consuming and prone to humanerror. Therefore, automated systems for monitoring individual animals are desired. Here, westudied whether individual broiler activity could be tracked using an ultra-wideband (UWB)system. Birds were fitted with UWB tags that sent out signals to four beacons. The location ofthe birds was determined using triangulation of the signal, allowing calculation of distancesmoved over time. Distances moved according to the UWB system were compared to thosefound on video for twelve birds. A moderately strong correlation between the UWB systemand video tracking was found (Repeated measures correlation, r=0.71 (95%-CI: 0.64-0.77),df=209, P<0.001). Furthermore, the UWB system was used for assessing individual levels ofactivity. In total, 137 birds from different genetic crosses were tracked near-continuously forseventeen consecutive days, starting on day 16 of life, and their weight was determined at thestart and end of this 17 d period. Data were analysed using an LME-model in R. First analysesshowed that activity, measured as the average distance moved, decreased over the seventeendays in all genetic crosses (F(1,127.00)=301.47, P<0.001). Furthermore, in all genetic crosses,birds with a lower weight at the start of the trial were on average more active (F(1,125.14)=9.16,P<0.01). Overall, the UWB system appears well-suited for activity monitoring in broilers andthe longitudinal information on individual differences in activity can potentially be used tomonitor health, welfare and performance at the individual level. Unfortunately, the UWBtags are too large and heavy for day-old chicks to wear and can only be implemented later inlife. Therefore, current work is focussing on the implementation of a passive radio frequencyidentification (RFID) system to track individual broiler activity, using smaller, lightweight tagsthat can be attached to the broilers’ legs at day-old. This system may be able to track individualactivity of broiler chickens throughout the entire life.
    Reduce damaging behaviour in laying hens and pigs by developing sensor technologies to inform breeding programs
    Rodenburg, T.B. ; Zande, Lisette van der; Haas, E.N. de; Kostal, L. ; Pichova, Katarina ; Piette, Deborah ; Tetens, Jens ; Visser, Bram ; Klerk, Britt de; Sluis, M. van der; Bennewitz, Jörn ; Siegford, Janice ; Norton, Tomas ; Guzhva, Oleksiy ; Ellen, E.D. - \ 2019
    In: Proceedings of the 53rd Congress of the International Society for Applied Ethology (ISAE). - Wageningen, The Netherlands : Wageningen Academic Publishers - ISBN 9789086863389 - p. 364 - 364.
    The COST Action GroupHouseNet aims to facilitate the prevention of damaging behaviourin group-housed pigs and laying hens. One area of focus is on how genetic and genomictools can be used to breed for animals that are less likely to develop damaging behaviour.The behaviours we are focusing on are feather pecking in laying hens and tail biting in pigs.Both species are kept in groups, and identifying actual performers of this behaviour (peckersand biters), and tracking them at the individual level remains challenging, but is essential forbreeding programs. It is possible to use traditional behavioural observation, but this is timeconsumingand costly. Sensor technology is a rapidly developing field and may offer solutionsfor phenotyping animals at the individual level. We propose that sensor technology combinedwith genomic methods may be useful in solving the problems of damaging behaviour in grouphousedpigs and laying hens. When evaluating the sensor technologies used until now, forlaying hens RFID and accelerometer-based approaches seem most promising. In pigs, computervision is already used to record technical performance, and there seems to be potential forexpanding this approach to the recording of damaging behaviour. If sensor signatures andgenomic fingerprints of individual animals can be combined, this would significantly improveour possibilities to reduce damaging behaviour through genetic selection.
    Automated tracking of individual activity of broiler chickens
    Sluis, M. van der; Klerk, B. de; Rodenburg, T.B. ; Haas, Y. de; Hijink, Thijme ; Ellen, E.D. - \ 2019
    Review of sensor technologies in animal breeding: Phenotyping behaviors of laying hens to select against feather pecking
    Ellen, Esther D. ; Sluis, Malou Van Der; Siegford, Janice ; Guzhva, Oleksiy ; Toscano, Michael J. ; Bennewitz, Jörn ; Zande, Lisette E. Van Der; Eijk, Jerine A.J. Van Der; Haas, Elske N. de; Norton, Tomas ; Piette, Deborah ; Tetens, Jens ; Klerk, Britt de; Visser, Bram ; Bas Rodenburg, T. - \ 2019
    Animals 9 (2019)3. - ISSN 2076-2615
    -omics - Computer vision - Damaging behavior - Genetic selection - Identification - Measuring behavior - Radio frequency identification - Ultra-wideband

    Damaging behaviors, like feather pecking (FP), have large economic and welfare consequences in the commercial laying hen industry. Selective breeding can be used to obtain animals that are less likely to perform damaging behavior on their pen-mates. However, with the growing tendency to keep birds in large groups, identifying specific birds that are performing or receiving FP is difficult. With current developments in sensor technologies, it may now be possible to identify laying hens in large groups that show less FP behavior and select them for breeding. We propose using a combination of sensor technology and genomic methods to identify feather peckers and victims in groups. In this review, we will describe the use of “-omics” approaches to understand FP and give an overview of sensor technologies that can be used for animal monitoring, such as ultra-wideband, radio frequency identification, and computer vision. We will then discuss the identification of indicator traits from both sensor technologies and genomics approaches that can be used to select animals for breeding against damaging behavior.

    Effect of growth regulators on multiplication and alkaloid production of narcissus tazetta var. italicus in tissue culture
    Shahin, Heba ; Klerk, G.J.M. de; El-Hela, Atef A. - \ 2018
    Propagation of ornamental plants 18 (2018)4. - ISSN 1311-9109 - p. 124 - 130.
    Two aspects of micropropagation of Narcissus tazetta, viz., contamination during initiation and multiplication were examined. A 30 min hot water treatment (HWT) of bulb segments at 40°C reduced contamination during initiation from 50% to less than 15%. After the HWT at 40°C, all explants survived and new shoot formation occurred in almost 100% of the explants, a noticeable increase relative to 70% in the nontreated control. The auxin transport inhibitor 2,3,5-triiodobezoic acid (TIBA) significantly (p < 0.01) increased shoot formation from twin scale explants. Fluridone, an inhibitor of strigolactone biosynthesis, increased shoot formation from scale explants a little. Newly formed shoots were rooted in vitro on medium with 0.5 µM indole-3-butyric acid (IBA). Plantlets with well-developed root and shoot systems were successfully acclimated (90%). They exhibited normal morphology and growth characteristics. Callus was initiated on different concentration of 2,4-dichlorophenoxyacetic acid (2,4-D) and 6-benzylaminopurine (BAP). In vitro tissues were screened for the production of alkaloids. In nondifferentiated callus, small amounts of galantamine occurred, which increased with tissue differentiation.
    A genome-wide association study for natural antibodies measured in blood of Canadian Holstein cows
    Klerk, Britt de; Emam, Mehdi ; Thompson-Crispi, Kathleen A. ; Sargolzaei, Mehdi ; Poel, Jan van der; Mallard, Bonnie A. - \ 2018
    Wageningen University and Research
    Genome-Wide Association Study - Natural antibody - Dairy cattle - Immune system - Veicle trafficking - Immunoglobulin class switching
    Background: Natural antibodies (NAb) are an important component of the innate immune system, and fight infections as a part of the first line defence. NAb are poly-reactive and can respond non-specifically to antigens. Therefore, NAb may be a key trait when evaluating an animal’s potential natural disease resistance. Variation in NAb is caused by both genetic and environmental factors. In this study genetic parameters of NAb were estimated and a genome-wide association study (GWAS) was performed to gain further understanding on the genes that are responsible for the observed genetic variation of NAb in Canadian Holsteins. Results In total, blood samples of 1327 cows from 64 farms were studied. NAb binding to keyhole limpet hemocyanin (KLH) were determined via indirect ELISA. Immunoglobulin (Ig) isotypes, IgG and IgM, were evaluated. From the sample population, 925 cows were genotyped for 45,187 markers and each individual marker was tested to detect genetic variation in NAb levels. The relationships among animals was accounted for with genomic relationship. Results show heritabilities of 0.27 ± 0.064 (IgG) and 0.31 ± 0.065 (IgM). In total, 23 SNPs were found to be associated with IgG, but no SNPs were associated with IgM (FDR p-value < 0.05). The significant SNPs were located on autosomal chromosomes 1, 20 and 21 of the cow genome. Functional annotation analysis of the positional candidate genes revealed two sets of genes with biologically relevant functions related to NAb. In one set, seven genes with crucial roles in the production of antibody in B cells were associated with the trafficking of vesicles inside the cells between organelles. In the second set, two genes among positional candidate genes were associated with isotype class-switching and somatic hypermutation of B cells. Conclusions This study demonstrated the possibility of increasing NAb through selective breeding. In addition, the effects of two candidate pathways are proposed for further investigation of NAb production in Holsteins.
    Negative hydrostatic pressure is an unnoticed but significant source of contamination in tissue culture
    Askari, N. ; Klerk, G.J. de - \ 2018
    In: Proceedings of the 2017 Annual Meeting of the International Plant Propagators' Society. - International Society for Horticultural Science (Acta Horticulturae ) - ISBN 9789462612099 - p. 85 - 87.
    Plants are characterized by a negative hydrostatic pressure, brought about by transpiration and by capillary activity of xylem vessels (Taiz and Zeiger, 2010). Because of this, a stem that is being cut sucks up what is nearby. Often this is air but it may also be liquid. The diameter of the xylem vessels is 50-100 μm, so when the liquid contains bacteria (that are typically 0.5-5.0 μm), they will enter deeply into the tissue (Askari et al., 2014; De Klerk et al., 2014). To our knowledge, this alleged source of contamination has never been examined.
    A genome-wide association study for natural antibodies measured in blood of Canadian Holstein cows
    Klerk, Britt de; Emam, Mehdi ; Thompson-Crispi, Kathleen A. ; Sargolzaei, Mehdi ; Poel, Johan J. van der; Mallard, Bonnie A. - \ 2018
    BMC Genomics 19 (2018)1. - ISSN 1471-2164
    Dairy cattle - Genome-wide-association study - Immune system - Immunoglobulin class switching - Natural antibody - Vesicle trafficking

    Background: Natural antibodies (NAb) are an important component of the innate immune system, and fight infections as a part of the first line defence. NAb are poly-reactive and can respond non-specifically to antigens. Therefore, NAb may be a key trait when evaluating an animal’s potential natural disease resistance. Variation in NAb is caused by both genetic and environmental factors. In this study genetic parameters of NAb were estimated and a genome-wide association study (GWAS) was performed to gain further understanding on the genes that are responsible for the observed genetic variation of NAb in Canadian Holsteins. Results: In total, blood samples of 1327 cows from 64 farms were studied. NAb binding to keyhole limpet hemocyanin (KLH) were determined via indirect ELISA. Immunoglobulin (Ig) isotypes, IgG and IgM, were evaluated. From the sample population, 925 cows were genotyped for 45,187 markers and each individual marker was tested to detect genetic variation in NAb levels. The relationships among animals was accounted for with genomic relationship. Results show heritabilities of 0.27 ± 0.064 (IgG) and 0.31 ± 0.065 (IgM). In total, 23 SNPs were found to be associated with IgG, but no SNPs were associated with IgM (FDR p-value < 0.05). The significant SNPs were located on autosomal chromosomes 1, 20 and 21 of the cow genome. Functional annotation analysis of the positional candidate genes revealed two sets of genes with biologically relevant functions related to NAb. In one set, seven genes with crucial roles in the production of antibody in B cells were associated with the trafficking of vesicles inside the cells between organelles. In the second set, two genes among positional candidate genes were associated with isotype class-switching and somatic hypermutation of B cells. Conclusions: This study demonstrated the possibility of increasing NAb through selective breeding. In addition, the effects of two candidate pathways are proposed for further investigation of NAb production in Holsteins.

    A Dutch perspective on urban growth boundaries : From containing to stimulating growth
    Janssen-Jansen, Leonie ; Tan, Wendy - \ 2018
    In: Instruments of Land Policy Taylor and Francis - ISBN 9781138201514 - p. 137 - 141.
    Within international planning educational circles, the Netherlands has long been held up as an exemplar of effective national and regional land use planning practices. Well-known examples are the water management policies (van der Cammen and de Klerk 2012). The clearly defined administrative hierarchies, the policy consistency, and the management of the land resource with governmental controls in planning have been praised in planning literature. The Dutch planning system is seen as a great example for other countries, just as Sullivan’s Portland example (Bontje 2003; Fainstein 2005). The urban growth boundary (UGB) of the Regional Framework Plan of Portland is likewise one of the most outstanding elements of the land use planning system in State of Oregon. This is an example of an instrument accompanied by many other complementary ordinances, regulations, and rules that together result in a desired planning outcome. The UGB is therefore often compared to national planning instruments in the Netherlands intent on enforcing a strict boundary between the urban and the rural. In the Netherlands, this divide has always been a keystone concept of the land use planning system, which is to keep as much open space ‘open’ as possible, while concurrently address the need for expansion and growth by ensuring enough land for residential development in a context of land scarcity in the upcoming decades. This is a similar situation to Portland where the growth necessary for the next 20 years needs to be balanced by the geographical constraints of the nature and agricultural areas. Although the regional UGB enjoys statutory status in Portland, regional coordination is considered an informal norm within the Netherlands. For example, certain provinces keep to an 80–20 rule, whereby the majority of new developments should take place within existing urban contours. The regional focus of Portland’s planning system is relevant for international planners as most land use issues tend to cross administrative borders in nature and involve more than a single government level. On the surface, the Dutch planning system might not have much to offer as compared to Portland as the legal force is maintained mostly at the local level in the form of municipal land use plans (Needham 2016). Although the 2008 revision of the planning law (WRO 2008) does enable regional and inter-municipal zoning plans 138that can be brought forward by multiple municipalities or proposed by the Dutch regional government – the province – this instrument has been hardly implemented. From the provincial perspective, ‘overthrowing’ municipalities is politically not popular; municipalities – and their governors – focus on the land in their municipality as they are accountable for planning within the municipality, not outside.
    Physiological and anatomical factors determining the water balance and hyperhydricity in Arabidopsis seedlings
    Kemat, N. ; Visser, R.G.F. ; Klerk, G.J.M. de; Krens, F.A. - \ 2017
    Lunteren Lectures
    Trichloroacetate, an inhibitor of wax biosynthesis, prevents the development of hyperhydricity in Arabidopsis seedlings
    Klerk, Geert Jan de; Pramanik, Dewi - \ 2017
    Plant Cell, Tissue and Organ Culture: an international journal on in vitro culture of higher plants 131 (2017)1. - ISSN 0167-6857 - p. 89 - 95.
    Cuticula - Cuticular transpiration - Hyperhydricity - Intercellular spaces - Trichloroacetate - Wax
    Arabidopsis seedlings developed severe hyperhydricity (HH) when 0.2% Gelrite was used to solidify the medium instead of 0.7% agar. One mM trichloroacetate (TCA, an inhibitor of wax synthesis) strongly reduced the amount of wax. TCA also strongly increased the permeability of leaves for water as shown by a decrease of the water retention capacity. One mM TCA also fully prevented HH: the visible symptoms of HH were absent and the amounts of water and air in the intercellular spaces were as in normal, nonhyperhydric seedlings. Apparently, the excess of water that caused the symptoms of HH had been removed by the increased cuticular transpiration in the presence of 1 mM TCA.
    Check title to add to marked list
    << previous | next >>

    Show 20 50 100 records per page

     
    Please log in to use this service. Login as Wageningen University & Research user or guest user in upper right hand corner of this page.