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The impact of light on vase life in (Anthurium andraeanum Hort.) cut flowers
No full textThe impact of light quality and quantity on vase life was investigated using Anthurium (Anthurium andraeanum Hort.). Cultivars ‘Spirit’ and ‘Honduras’, were chosen based on their contrasting vase life in previous studies, and designated as ‘Vshort’ and ‘Vlong’ respectively. Both cultivars were kept under three light regimes at 12 h day length: fluorescent lights of 40 μmol m-2 s-1, low intensity LEDs producing light at 40 μmol m-2 s-1 and high intensity LEDs producing light at 400 μmol m-2 s-1. Degradation, water uptake and hyperspectral reflectance were measured three times a week as the cut flowers degraded. Spadix necrosis was used to quantify cut flower degradation over time and to determine the vase life for each cultivar. Light regime had a significant impact on vase life and water uptake in Vlong but not in Vshort, with high intensity LEDs resulting in a marked increase in the vase life of Vlong. The rate of water uptake was higher for Vshort, while Vlong maintained moderate and steady water uptake over time, particularly under high intensity LEDs. The reflectance spectrums changed during spathe degradation, with different responses seen in each cultivar. Reflectance spectrums showed consistent changes in the ‘red dip index’ (R800-R685), with Vshort demonstrating an increase in reflectance of red light over time while Vlong increased its absorption of red light over time. Extension of vase life under high intensity light was cultivar-dependent, revealing a previously unknown interaction between light and vase life. The absence of any interaction in the short vase life cultivar suggests that this mechanism is linked to genotypic differences in vase life, while the contrasting reflectance profiles suggest that pigment turnover is important for regulating this mechanism
Genotypic differences in vase life of Anthurium andraeanum (Hort.) cut-flowers are associated with differences in spathe chlorophyll content
No full textAnthurium (Anthurium andraeanum (Hort.)) is an important crop in the worldwide cut-flower industry, valued in particular for its showy colors and long vase life, which varies from a few days to several weeks depending on the cultivar. Previous work suggested that long vase life is associated with the chlorophyll content of the spathe, especially when more light is available. Here we compare the vase life of ten anthurium cultivars covering a range of chlorophyll contents, using two light intensities: low light (40 µmol m −2 s −1) and high light (400 µmol m −2 s −1). The experiment was arranged in a factorial design with six replicate cut-flowers per cultivar per light intensity, and measurements were recorded weekly for cut-flower degradation, water uptake, spathe chlorophyll content and spathe hyperspectral reflectance. Cultivar differences in vase life were positively associated with differences in the initial spathe chlorophyll content (accounting for > 60 % of the variation). The use of high light also significantly increased vase life in three of the high chlorophyll cultivars. Chlorophyll content increased over time in some cultivars, and this increase was associated with extended vase life under high light (accounting for 69 % of the variation). In both cases chlorophyll content provided a better indicator of vase life than the red dip index (R800 nm – R685 nm) derived from hyperspectral reflectance. The results show that cultivars with a high initial chlorophyll content often have an ability to ‘re-green’ by increasing chlorophyll content while in the vase. Both high initial chlorophyll content and the ability to perform re-greening are associated with a longer vase life suggesting that chlorophyll activity in the spathe helps to maintain the cut-flowers. </p
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Safe handling and movement of cocoa germplasm for breeding
Get PDFCocoa (Theobroma cacao L.) originated in South America, but is now cultivated in various parts of the tropics. Movement of cocoa germplasm is often required in breeding programmes to increase the genetic diversity pool or to test clones/progeny in the field. However, such movement brings with it the risks of spread of pests and diseases, many of which are confined to particular geographical locations. Thus, it is critical that movement of germplasm is conducted within a quarantine framework. This chapter reviews the risks associated with the movement of cocoa germplasm. It considers international governance of plant movement and discusses the International Cocoa Quarantine Centre at the University of Reading (ICQC,R) as a hub for safe handling and movement of cocoa germplasm
Genetics of resistance to cowpea severe mosaic virus (Trin.Isol.) and some important agronomic traits in Vigna unguiculata (L.) walp.
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Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
BetoCarib : Begomovirus disease management for sustainable production to tomato in Caribbean. Final report. 2002-2006 : INCO International scientific cooperation projects. Contract number: ICA4-2001-10002
Get PDFVariations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Begomovirus disease management for sustainable production to tomato in Caribbean. Annual report covering the period from 1 February 2002 to 31 January 2003 : INCO : International Scientific Cooperation Projects (1998-2002). Contract number : ICA4-2001-10002
No full textBegomovirus diseases transmitted by Bemisia tabaci are responsible for important economic losses in tomato crops in the Caribbean islands. Because of the limited resources of growers, the diversity of the agro-system and the fragility of the ecosystem, the management strategies must be multi component in nature and based on a thorough understanding of the pathosystem involved to ensure sustainable development. BETOCARIB aims to study the pathosystem Bemisia- begomovirus-host plants and their epidemics to develop models in order to identify keys factor involved in the development of epidemics. Integrated pest management strategies able to reduce the impact of the diseases on tomato crops will be developed from these models and tested in the various islands. This project will be achieved through three WPs: - WP A is devoted to the identification of begomoviruses, their relative incidence, their vectors and their respective host plants in order to develop specific tools for their detection. - WP B is focused on epidemiology studies in order to built an adequate agronomic model to predict begomovirus infestations. - WP C will define the adequate IPM strategies to control viruses based on the use of tolerant/resistant varieties, the cultural methods and prediction of infections due to the agronomic epidemic model developed. The results obtained during this first year concern the three WPs. Le viral status was clearly confirmed for Cuba and Dominican Republic where mixed infection by TYLCV/ToHMV and TYLCV alone occur respectively. Martinique and Guadeloupe have partially characterized a novel introduced begomovirus, TYLCV, in addition to PYMV already identified. Trinidad and Tobago has started to identify additional viruses different from begomovirus already characterized. Each partners had developed specific tools to begomoviruses already identified and had agreed on a unique common protocol to detect them, an hybridization using non radioactive probes. They have designed new primers for specific detection of NW and OW begomoviruses based on sequence alignment. These will be evaluated during the next year. All partners have selected Bemisia tabaci samples and sent them to the Partner P1 in France in order to precise the biotype using RAPDs and microsatelites markers. The first epidemic data collected from Guadeloupe was highly informative to adapt the I maximal model' proposed in order to define an ecosystem-based begomovirus disease risk prediction model. Protocols developed in Guadeloupe will be transferred and adapted to Cuba to test during the next year the hardiness of the keys factors suspected involved in the epidemics. In parallel, Cuba, Martinique and Trinidad were set up several trials to screen tomato varieties for their resistance to TYLCV and PYMV as well as resistance to nematodes and high temperature. At the beginning of the project, Partner P1 created a BETOCARIB Web site to formalise the interactions between consortium members and to keep us aware on the project progress. Due to these objectives, the Betocarib Web site has been divided into two parts: everybody can consult one and one restricted to members only. The web site can be accessed at the following address: htpp://betocarib.cirad.fr
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