895 resultados para Floral Abscission
Resumo:
Capparaceae comprises 25 genera and 480 species, of which 110 are included in 18 genera in Neotropics. Its distribution is pantropical with high frequency in seasonally dry environments. Its representatives are woody, shrubs and rarely wines, with simple leave or compound 3-foliolate, shorts and deciduous floral bracts, tetramerous and nocturnal flowers with exserts and numerous stamens, ovary supero on a gynophore and fleshy fruits, dehiscents or indehiscentes. For Brazil, 12 genera and 28 species are recorded and 12 of that are endemic to the country, occurring preferentially in vegetation of savanna estépica s.str., seasonal semideciduos forest and restinga. This work shows two chapters. In the first chapter, the distributions patterns of the species occurring in the brazilian semi-arid region and their distribution intra Caatinga are discussed. The distribution patterns were determined from a review of the distribution of species in herbaria collections and supplemented with data obtained from specific bibliography about the family. A map containing 1 × 1 grid cells was used to evaluate the richness, collection efforts and floristic similarity of the species intra Caatinga. Six genera and eight species were registered in Caatinga. Four species are endemic to Brazil, with only one endemic to Caatinga, and the other four are widespread in Neotropics. Four distribution patterns were observed: restricted to the NE, broad and continuous in Brazil, disjunct and neotropical. All the species were recorded in Bahia, state with the highest species richness per grid cell and also remarkable sampling efforts species of the family. The state of Piauí presents priority areas for further collection of Capparaceae, due to low family representation in the state. The floristic similarity analysis intra Caatinga was low, 22 %, probably due to a few species of the family in the region and the wide distribution of the same. The second chapter presents the Capparaceae of flora to Rio Grande do Norte (RN), since the state has a little-known flora, with specific studies. Through collections in the state and herbaria review, five genera and six species of Capparaceae were recorded in RN: Capparidastrum (1 spp.); Crateva (1 spp.); Cynophalla (2 spp.); Mesocapparis (1 spp.) and Neocalyptrocalyx (1 spp.). Capparidastrum frondosum and Mesocapparis lineata are new records for the state. An identification key, descriptions and images, comments on the biology of the species and protected areas where they occur are showed.
Resumo:
We evaluated whether heating occurs in sub-Antarctic megaherbs, and the relation of heating to relevant environmental variables. We measured leaf and inflorescence temperature in six sub-Antarctic megaherb species on Campbell Island, latitude 52.3°S, New Zealand Biological Region. Using thermal imaging camera (Fluke TI20, http://www.fluke.com/fluke/caen/support/software/ti-update) and thermal probe (Fluke 51 II digital thermal probe), in combination with measurement of solar radiation, ambient air temperature, wind speed, wind chill and humidity.
Resumo:
Le genre Angraecum est un groupe d’orchidées tropicales qui compte environ 221 espèces réparties en Afrique subsaharienne, dans l’ouest de l’Océan Indien, et au Sri Lanka. Plus de la moitié des espèces se trouvent à Madagascar, dont au moins 90% sont endémiques à l’île. L’étude systématique et taxonomique du genre Angraecum a toujours été problématique à cause de sa grande diversité morphologique. Pour faciliter la classification, des sections ont été établies dont la plus connue est celle de Garay (1973), qui regroupe les espèces sous 19 sections. Plusieurs analyses phylogénétiques avaient montré que le genre Angraecum et les sections de Garay ne sont pas monophylétiques. Cependant, aucune révision systématique n’a été apportée à cause du faible échantillonnage dans ces analyses. En incorporant un plus grand nombre d'espèces et en ajoutant d’autres caractères morphologiques dans l’analyse, nous avons apporté une plus grande résolution à la reconstruction phylogénétique du groupe. Cette résolution concerne surtout les nœuds plus profonds qui représentent les différents clades à l’intérieur d'Angraecum, qui correspondent à des sections naturelles. A partir de ces clades, nous avons redéfini 14 sections monophylétiques toute en reconnaissant cinq nouvelles. Grâce à cette nouvelle phylogénie d'Angraecum, nous avons pu étudier la diversification du genre et de la sous-tribu Angraecinae en utilisant des méthodes macroévolutives, notamment les roles joués par les traits floraux dans la spéciation, tout en l'interprétant grâce aux histoires géologique et paléoclimatique. Le modèle de diversification chez les Angraecinae semble avoir été celui communément rencontré dans les forêts tropicales humides, c’est-à-dire une diversification par accumulation graduelle d’espèces à travers le temps et non pas une radiation adaptative rapide, comme souvent observée chez des lignées animales malgaches. Plusieurs caractères morphologiques jouent un rôle important dans la diversification des espèces d'Angraecum. Le début de la diversification d'Angraecum à Madagascar coïncide avec le mouvement progressif de l’île vers le nord, l’établissement de la mousson dans la partie nord de l’île durant le Miocène, et l’expansion de la forêt tropicale malgache pendant cette période. Notre étude de l’histoire biogéographique des Angraecinae suggère une origine malgache de la sous-tribu et du genre Angraecum. On observe de la dispersion à longue distance à partir de Madagascar vers le reste du monde dans le genre Angraecum. La forêt tropicale humide du Nord Est de Madagascar est le point de départ de la diversification des espèces d'Angraecum. Le premier événement de dispersion a débuté à l’intérieur de l’île vers la fin du Miocène. Cet évènement est marqué par une migration du Nord Est vers le centre de Madagascar. Par ailleurs, la majorité des événements de dispersion à longue distance se sont produits durant le Pliocène-Pléistocène à partir soit du centre, soit du Nord Est de l'île. On assiste à des migrations indépendantes vers l’Afrique de l’est et les Comores d’une part, et vers les Mascareignes d’autre part. Un seul événement fondateur ayant conduit à l’apparition de la section Hadrangis est observé dans les Mascareignes. La saison cyclonique joue un rôle significatif dans la dispersion à longue distance des graines d’orchidées, comparée aux vents dominants qui soufflent dans la région ouest de l’Océan Indien, notamment l’alizé et la mousson. La similarité des niches écologiques a facilité l’expansion des espèces d'Angraecum dans les Comores et les Mascareignes.
Resumo:
Polygonal tundra, thermokarst basins and pingos are common and characteristic periglacial features of arctic lowlands underlain by permafrost in Northeast Siberia. Modern polygonal mires are in the focus of biogeochemical, biological, pedological, and cryolithological research with special attention to their carbon stocks and greenhouse-gas fluxes, their biodiversity and their dynamics and functioning under past, present and future climate scenarios. Within the frame of the joint German-Russian DFG-RFBR project Polygons in tundra wetlands: state and dynamics under climate variability in Polar Regions (POLYGON) field studies of recent and of late Quaternary environmental dynamics were carried out in the Indigirka lowland and in the Kolyma River Delta in summer 2012 and summer 2013. Using a multidisciplinary approach, several types of polygons and thermokarst lakes were studied in different landscapes units in the Kolyma Delta in 2012 around the small fishing settlement Pokhodsk. The floral and faunal associations of polygonal tundra were described during the fieldwork. Ecological, hydrological, meteorological, limnological, pedological and cryological features were studied in order to evaluate modern and past environmental conditions and their essential controlling parameters. The ecological monitoring and collection program of polygonal ponds were undertaken as in 2011 in the Indigirka lowland by a former POLYGON expedition (Schirrmeister et al. [eds.] 2012). Exposures, pits and drill cores in the Kolyma Delta were studied to understand the cryolithological structures of frozen ground and to collect samples for detailed paleoenvironmental research of the late Quaternary past. Dendrochronological and ecological studies were carried out in the tree line zone south of the Kolyma Delta. Based on previous work in the Indigirka lowland in 2011 (Schirrmeister et al. [eds.] 2012), the environmental monitoring around the Kytalyk research station was continued until the end of August 2012. In addition, a classical exposure of the late Pleistocene permafrost at the Achchaygy Allaikha River near Chokurdakh was studied. The ecological studies near Pokhodsk were continued in 2013 (chapter 13). Other fieldwork took place at the Pokhodsk-Yedoma-Island in the northwestern part of the Kolyma Delta.
Resumo:
The distribution of diatoms, coccolithophores and planktic foraminifers mirrored the hydrographic and trophic conditions of the surface ocean (0-100 m) across the upwelling area off the Oman coast to the central Arabian Sea during May/June 1997 and July/August 1995. The number of diatoms was increased in waters with local temperature minimum and enhanced nutrient concentration (nitrate, phosphate, silicate) caused by upwelling. Vegetative cells of Chaetoceros dominated the diatom assemblage in the coastal upwelling area. Towards the more nutrient depleted and stratified surface waters to the southeast, the number of diatoms decreased, coccolithophore and planktic foraminiferal numbers increased, and floral and faunal composition changed. In particular, the transition between the eutrophic upwelling region off Oman and the oligotrophic central Arabian Sea was marked by moderate nutrient concentration, and high coccolithophore and foraminifer numbers. Florisphaera profunda, previously often referred as a 'lower-photic-zone-species', was frequent in water depths as shallow as 20 m, and at high nutrient concentration up to 14 µmol NO3/l and 1.2 µmol PO4/. To the oligotrophic southeast of the divergence, cell densities of coccolithophores declined and Umbellosphaera irregularis prevailed throughout the water column down to 100 m depth. In general, total coccolithophore numbers were limited by nutrient threshold concentration, with low numbers (<10*10**3 cells/l) at high [NO3] and [PO4], and high numbers (>70*10**3 cells/l) at low [NO3] and [PO4]. The components of the complex microplankton succession, diatoms, coccoliths and planktic foraminifers (and possibly others), should ideally be used as a combined paleoceanographic proxy. Consequently, models on plankton ecology should be resolved at least for the seasonality, to account for the bias of paleoceanographic transfer calculations.
Resumo:
This article-based thesis focuses on the formation of vocational knowing within adult and upper secondary floristry education in Sweden. Three articles explore classroom interaction and assessment actions; a fourth considers changes in vocational subject matter during the period 1990–2015. While the first three articles draw on empirical data in the form of video and audio recordings in combination with participant observation, the fourth is based primarily on material-based interview data. All four articles share a sociocultural perspective on educational practice (Wertsch, 1998; Säljö, 2011, 2013) and a relational view of knowing (e.g., Carlgren, 2015; Molander, 1996), in combination with the use of conversation analysis (Goodwin & Heritage, 1990; Sahlström & Melander, 2010) as a tool to illuminate the formation of vocational knowing. The interaction between teacher, student, and floral arrangement is foregrounded to facilitate analysis of the formation of vocational knowing. The results contribute to our understanding of the schooling of the gaze (Goodwin, 1994; Grasseni, 2009, 2011) as appropriated by participants in the interaction. Floristry vocational knowing is shown to evolve in the temporal dimension, encompassing (a) financial and aesthetic values, (b) verbal and non–verbal communication, (c) botanical material and tools, and (d) making. The respective roles and interrelations of these four components of vocational knowing in floristry are discussed. The contribution of the thesis is twofold. First, these articles contribute to the understanding of vocational education through close appraisal of the formation of vocational knowing. Second, in exploring the previously under-researched field of Swedish floristry vocational education, the thesis bridges a gap in existing knowledge of the evolution of Swedish vocational education. As floristry education is little researched internationally, the thesis also contributes to the wider body of international research.