9 research outputs found
Projects around the Lake of Tunis in the face of crises
LâavĂšnement de lâurbanisme de projet en Tunisie a Ă©tĂ© caractĂ©risĂ© depuis le dĂ©but des annĂ©es 2000 par lâarrivĂ©e de bailleurs de fonds Ă©trangers autour des marges urbaines dans la mĂ©tropole de Tunis. Le waterfront tunisois sâest dĂ©veloppĂ© partiellement, comportant de fortes inĂ©galitĂ©s entre la Rive-Nord et la Rive-Sud. Alors que le premier projet (Berges du Lac Nord), bien quâaffectĂ© par des blocages, des retards et mĂȘme des arrĂȘts partiels, a pu rĂ©sister aux derniĂšres « crises » vĂ©cues par la Tunisie - la crise financiĂšre mondiale (dĂšs 2008) et la « crise politique » gĂ©nĂ©rĂ©e par la RĂ©volution de 2011 - le deuxiĂšme grand projet (Berges du Lac Sud) est restĂ© toujours en attente. Entre temps, des sociĂ©tĂ©s de projet ont Ă©tĂ© crĂ©Ă©es, en partenariat avec des investisseurs Ă©trangers : la SPLT et la SEPTS. Comment les projets du Lac du Tunis sâarticulent avec lâurbanisme du Grand Tunis ? Comment les sociĂ©tĂ©s de projet sâarticulent avec la structure institutionnelle existante ? Ă partir dâune Ă©tude menĂ©e sur les temporalitĂ©s et lâinternationalisation des projets, nous cherchons Ă montrer, dâune part, les « adaptabilitĂ©s » de lâamĂ©nagement, des pratiques et des projets dâurbanisme face aux contraintes/opportunitĂ©s auxquelles ils sont confrontĂ©s, et Ă illustrer dâautre part la logique de la promotion fonciĂšre et immobiliĂšre sur le processus de mĂ©tropolisation de Tunis. Enfin, nous avons effectuĂ© une Ă©valuation de la qualitĂ© urbaine entre « le conçu » et « le rĂ©alisĂ© » Ă partir des reprĂ©sentations et des pratiques des usagers autour des Berges du Lac Nord.Urban planning in Tunisie begain in the early 2000s with the arrival of forgein donors around the urban margins in the metropolis of Tunis. The Tunisian waterfront has been partially developed, with strong inequalities between the northen and southern shores. Despite constrained blockages, delays, and even partial stops, the first project (North Lake Banks), survived the last âcrisesâ in Tunisia - the global financial crisis (as early as 2008) and the âpolitical crisisâ resulting from the 2011 Revolution. However, the second major project (South Lake Banks) remained on hold. In the meantime, project companies were set up, in partnership with foreign investors (the SPLT and the SEPTS). How do the projects of the Lake of Tunis relate to the urban planning of the Greater Tunis? How do project companies relate to the existing international structure? Based on a study of emporality and project internationalization, we hope to demonstrate the adaptability of planning, practices, and urban planning projects to both constraints and opportunities and to illustrate the reasoning behind land and property development on the processus of metropolization in Tunis. Finally, we carried out an evaluation of the urban quality between the âdesignedâ and the ârealizedâ from the representations and practices of users on the banks of the North Lake
Les projets autour du Lac de Tunis face aux crises
La thĂšse a pour objet lâĂ©tude de lâavĂšnement de lâurbanisme de projet en Tunisie, soutenu par des bailleurs de fonds Ă©trangers, plus particuliĂšrement dans lâaire mĂ©tropolitaine de Tunis. Le waterfront tunisois ne sâest dĂ©veloppĂ© que partiellement, avec des fortes inĂ©galitĂ©s entre la rive Nord et la rive Sud. Les amĂ©nagements qui le concernent ont par ailleurs connu des Ă©volutions diverses : alors que le premier, celui des Berges du Lac Nord, a pu rĂ©sister aux derniĂšres « crises » subies par l..
Efficient Haploid Production on 'Wilking' Mandarin by Induced Gynogenesis
International audienceSeedlessness is a major criterion for the citrus fresh fruit market. Therefore, triploidy breeding appears very promising for the selection of new citrus cultivars. CIRAD has developed a method to produce triploid hybrids by somatic hybridization between diploid and haploid lines and demonstrate the potential for haploid citrus production by induced gynogenesis in clementine. In this work we analyzed the efficiency of induced gynogenesis by irradiated pollen in 'Wilking' mandarin (Citrus reticulata). Four doses of gamma irradiation of 'Meyer' lemon pollen were tested (150, 200, 250, 300 Grays). Embryos were extracted from small seeds, obtained in immature fruits, and cultivated in vitro. The ploidy level of plantlets was determined by flow cytometry analysis. Irradiated pollen appeared to be efficient for gynogenesis induction in 'Wilking'. A relatively high number of haploids (7 plantlets) was obtained, essentially after hybridisation with pollen irradiated at 250 Grays. The ploidy level of all haploid plantlets was confirmed by chromosome count. These haploid lines should be useful for triploid breeding by somatic hybridisation and also constitute interesting resources for genomic studies
Induced parthenogenesis in mandarin for haploid production: induction procedures and genetic analysis of plantlets
International audienceThis study focused on haploid induction in mandarin through in situ gynogenesis by pollination with irradiated pollen of âMeyerâ lemon. Pollination was carried out for three genotypes of mandarin with four levels of gamma-ray-irradiated pollen (150, 300, 600, and 900 Gy). The resulting seeds were characterised by a small size. Embryos were rescued in vitro and the ploidy level of the plantlets was determined by flow cytometry analysis. Haploid, diploid, triploid plantlets were obtained. The haploid parthenogenetic origin was confirmed using microsatellite marker analysis and chromosome count. Diploid and triploid plants were the result of crosses between mandarin and lemon. The induction of gynogenetic haploids of âFortuneâ (Citrus clementina Hort ex Tan. Ă Citrus tangerina Hort ex Tan.) and âEllendaleâ (Citrus reticulata Blanco Ă Citrus sinensis L. Osb) is reported here for the first time