References of "Saad, Layla"
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See detailPatterns of hybridization and hybrid survival in the invasive alien Fallopia complex (Polygonaceae)
Saad, Layla ULg; Tiébré, Marie-Solange; Hardy, Olivier et al

in Plant Ecology and Evolution (2011), 144(12-18),

Background -- Hybridization and polyploidization are considered important driving forces of invasive processes. In the invasive Fallopia spp. complex, hybridization between taxa of various ploidy levels ... [more ▼]

Background -- Hybridization and polyploidization are considered important driving forces of invasive processes. In the invasive Fallopia spp. complex, hybridization between taxa of various ploidy levels has been experimentally demonstrated. Extensive genetic variation has also been observed among hybrids in the field. However, what makes a certain hybridization event of evolutionary importance is still the subject of speculation considering the invasive potential of hybrid Fallopia. Aims -- The present study examined landscape scale patterns of interspecific hybridization within the alien invasive Fallopia complex, and tested whether cold winter might act as selective agent for hybrid survival. Methods -- Eighty seeds per clone were collected from four taxa (F. japonica, F. sachalinensis, F. aubertii, and F. xbohemica) and sown in greenhouse and outdoor conditions. Ploidy levels of the resulting seedlings were determined by flow cytometry at early stages of seedling growth and compared to those of mature clones present in the same landscapes. Key results -- The four studied taxa were involved in interspecific hybridization patterns. Seedlings resulting from hybridization had a large range of ploidy levels, including aneuploid and euploid progeny, and polyploid levels that were not observed in mature clones. Cold winter had a negative effect on germination success. However, a comparison of ploidy levels of seedlings that survived the cold winter with those grown under greenhouse conditions indicated that cold winter was not a significant selection agent for particular ploidy levels. Conclusions -- Our results stress the importance of interspecific hybridization and polyploidization events in generating invasive hybrids in the alien Fallopia spp complex. Cold winter represents a selection agent for the survival of early stages of progeny but does not explain the discrepancies in ploidy levels between produced seedlings and currently occurring mature clones. [less ▲]

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See detailPotentiel évolutif du complexe invasif Fallopia en Europe
Vanderhoeven, Sonia ULg; Saad, Layla ULg; Mahy, Grégory ULg

Scientific conference (2010, April)

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See detailDecline Of Endemic Oncocyclus Irises (Iridaceae) Of Lebanon: Survey And Conservation Needs
Saad, Layla ULg; Talhouk, Salma; Mahy, Grégory ULg

in Oryx (2009), 43(1), 91-96

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See detailInvasions biologiques: un peu de vocabulaire
Jacquemart, Anne-Laure; Vervoort, Arnaud; Lhoir, P. et al

in Silva Belgica (2009)

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See detailMolecular And Morphological Variation Of Rare Endemic Oncocyclus Irises (Iridaceae) Of Lebanon
Saad, Layla ULg; Mahy, Grégory ULg

in Botanical Journal of the Linnean Society (2009), 159

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See detailLes plantes exotiques envahissantes en Belgique ont-elles des impacts?
Saad, Layla ULg; Jacquemart, Anne-Laure; Cawoy, Valérie et al

in Parcs & Réserves (2009), 64(4), 10-16

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See detailContribution Of Delayed Autonomous Selfing To Reproductive Success In Kosteletzkya Virginica
Ruan, Cj.; Zhou, Lj.; Zeng, Fy. et al

in Belgian Journal of Botany (2008), 141(1), 3-13

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See detailLandscape Dynamics And Habitat Selection By The Alien Invasive Fallopia (Polygonaceae) In Belgium
Tiebre, Marie-Solange; Saad, Layla ULg; Mahy, Grégory ULg

in Biodiversity & Conservation (2008), 17(10), 2357-2370

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See detailHybridisation efficiency in generating Hybridisation efficiency in generating invasive progeny in the alien Fallopia (Polygonaceae) complex
Saad, Layla ULg; Tiébré, Marie-Solange; Hardy, Olivier et al

Poster (2007, November 16)

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See detailPhytoremediation of contaminated sites in urban environment : preliminary results of a study focussed on Lubumbashi.
Colinet, Gilles ULg; Saad, Layla ULg; Cubaka, Alfred et al

Conference (2007, July)

A specific flora has developped in Central Africa on soils which are naturally rich in Cu and Co. Mining and ore treatment activities in the Katanga province (RDC) have generated contaminations which do ... [more ▼]

A specific flora has developped in Central Africa on soils which are naturally rich in Cu and Co. Mining and ore treatment activities in the Katanga province (RDC) have generated contaminations which do endanger ecosystem viability and/or human health. A survey of edaphic conditions prevailing for plant growing in natural metalliferous outcrops, the « copper hills », in mining sites (quarries), and in contaminated areas around metal smelters, is conducted as a first stage of a phytoremediation-based research program. Soluble, available and total content in some metallic trace elements have been measured. The first results show a relatively high heterogeneity inside and between sites. But the main finding is related to the very different nature of contamination between the three types of sites. This point constitutes an additionnal difficulty that should be taken into account for the selection of metallophytic species from the copper hills or the quarries in order to vegetalize a site contaminated by atmospheric fall outs from metal smelters in Lubumbashi. [less ▲]

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See detailHybridization And Sexual Reproduction In The Invasive Alien Fallopia (Polygonaceae) Complex In Belgium
Tiebre, Ms.; Vanderhoeven, Sonia ULg; Saad, Layla ULg et al

in Annals of Botany (2007), 99(1), 193-203

† Background and Aims The knotweed complex, Fallopia spp. (Polygonaceae), belongs to the most troublesome invasive species in Europe and North America. Vegetative regeneration is widely recognized as the ... [more ▼]

† Background and Aims The knotweed complex, Fallopia spp. (Polygonaceae), belongs to the most troublesome invasive species in Europe and North America. Vegetative regeneration is widely recognized as the main mode of reproduction in the adventive regions. However, the contribution of sexual reproduction to the success of these invasive species has only been detailed for the British Isles. An examination was made as to how hybridization may influence the sexual reproduction of the complex in Belgium and to determine how it may contribute to the dispersal of the species. † Methods Studies were made of floral biology, reproductive success, seed rain, seed bank, germination capacity, seedling survival and dispersal capacity in order to characterize the reproductive biology of the species. Moreover, chromosome counts and flow cytometry were used to assess the hybrid status of seedlings produced by sexual reproduction. † Key Results In the area investigated, extensive sexual reproduction by hybridization within the complex, including one horticultural species, was demonstrated. A small percentage of seeds may be dispersed outside the maternal clone (.16 m) allowing the formation of genetically differentiated individuals. Seed germination was possible even after a winter cold period. †Conclusions The extensive sexual reproduction by hybridization could further contribute to the dramatic invasive success of knotweeds in Belgium and should not be underestimated when considering control and management measures. [less ▲]

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See detailAlien invasive species and climate change: overview of research activities
Vanderhoeven, Sonia ULg; Saad, Layla ULg; Tiébré, Marie-Solange et al

Poster (2007)

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See detailBimodal pollination system in rare endemic Oncocyclus irises (Iridaceae) of Lebanon
Monty, Arnaud ULg; Saad, Layla ULg; Mahy, Grégory ULg

in Canadian Journal of Botany (2006), 84(8), 1327-1338

Pollination systems based on indirect rewards, such as heat and shelter, have seldom been studied. Plant-pollinator interactions were characterized in Iris cedretii Dinsmore ex Chaudhary and Iris sofarana ... [more ▼]

Pollination systems based on indirect rewards, such as heat and shelter, have seldom been studied. Plant-pollinator interactions were characterized in Iris cedretii Dinsmore ex Chaudhary and Iris sofarana subsp. kasruwana Dinsmore ex Chaudhary, rare endemic Lebanese Oncocyclus irises exhibiting potential adaptation to shelter pollination. Despite a diversity of floral visitors (47 species), only two groups of Anthophoridae male bees (Xylocopa spp. and Eucera spp.) could be considered as efficient pollinators on the basis of frequency of visits, visiting behaviour, and pollen load. Lebanese Oncocyclus irises showed a bimodal pollination system with (1) diurnal visits at low rates but with potentially large pollen transfers by Xylocopa bees, exhibiting a foraging-like behaviour, principally during warm periods of the day and (2) sheltering, especially Eucera male bees, during night and day when the weather is changeable. Refuge occurrence in flowers was more important during the night (27%) than during the day (12%) and, for daytime, during cloudy or windy than sunny conditions. It also varied depending on the exposure of floral tunnels. Visitation rates of both day-visiting Xylocopa and night-sheltering Eucera were negatively associated with an increase of the number of flowers per clump. No experimental evidence was found showing that the principal advantage for male bees to shelter in Iris flowers was to fly earlier in the morning. [less ▲]

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See detailHybridization and polyploidy: driving forces of evolutionary processes in the Fallopia spp complex
Vanderhoeven, Sonia ULg; Saad, Layla ULg; Tiébré, Marie-Solange et al

Conference (2006)

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See detailHanging in there by a fall – The Oncocyclus of Lebanon
Saad, Layla ULg; Khuri, Sawsan

in British Iris Society Yearbook (2003)

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