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. / Angraecum is a group of tropical orchids that includes ca. 221 species distributed in Sub-Saharan Africa, the western Indian Ocean region, and Sri Lanka. At least half of the species are found in Madagascar, 90% being endemic to the island. Taxonomic studies of Angraecum have always been problematic because of the great morphological diversity of the group. To facilitate classification, sections have been proposed, the best-known system to date being that of Garay (1973) that subdivides the genus into 19 sections. Previous phylogenetic studies had shown that genus Angraecum and Garay’s sections are not monophyletic. However, no systematic review was made because of a reduced species sample in these analyses. Using a greater sampling from Madagascar and adding morphological characters to the analyses, we brought greater resolution to the phylogenetic reconstruction of the group. This resolution mainly concerns the deeper nodes representing different clades within Angraecum, which basically correspond to natural sections. By using these clades, we redefined 14 sections and recognized five new ones. Using this phylogeny of Angraecum, we evaluated species diversification using macroevolutionary methods, essentially the effect of floral traits in speciation. The great diversity of Angraecum species in Madagascar, the high endemicity, and the geology and paleoclimate histories allowed us to evaluate diversification patterns within the genus as well as sub-tribe Angraecinae. The model of diversification in Angraecinae follows that of most tropical rain forest taxa, which results from the gradual accumulation of species through time and not from a rapid adaptive radiation, as is often the case for Malagasy fauna lineages. Several morphological characters are involved in the diversification of Angraecum. The beginning of Angraecum diversification in Madagascar coincided with the progressive movement of the island northwards, the establishment of a monsoon regime in the northern part of the island during the Miocene, and the expansion of the Malagasy rainforest during that period. Our historical biogeographic study of Angraecinae suggests a Malagasy origin of the subtribe Angraecinae and Angraecum. We observed out-of Madagascar long-distance dispersal in Angraecum. The north-eastern Malagasy rainforest is the center of species radiation for the genus. The first dispersal event within the island started in the late Miocene. This event was a migration from the north to the central highland. The majority of long-distance dispersal events outside Madagascar occurred during the Pliocene-Pleistocene, originating from either the center or the North East of the island. There were multiple independent dispersals to East Africa and the Comoros, and to the Mascarenes. A single founder-effect event in section Hadrangis is observed in the Mascarenes. The cyclonic seasons play a significant role in long-distance dispersal of orchid seeds, as compared to prevailing winds in the western Indian Ocean region, essentially trade wind and monsoon. Ecological niche similarity favored the expansion of Angraecum species in the Comoros and Mascarene archipelagos.

The aim of master´s thesis is analysis of utilization of large-capacity battery energy storage systems, used in cooperation with facility Červený mlýn to supply ancillary services to ČEPS, a.s.. In the first part, categorisation of ancillary services is presented. Within the categorisation technical and legislative requirements on subjects providing individual services are defined, the overview of ancillary services providers is listed and the mechanisms of ancillary services procurement are elucidated. The thesis continues with an overview of accumulation technologies used in high-capacity application around the world and in Czech republic. Subsequently three technologies are presented – Li-Ion, NaS and VRB, which are considered as suitable technological solutions for given application. The last part of thesis deals with specification of parameters of the accumulation system, with selection of installation site within the facility and with description of operating modes while providing ancillary services. In order to evaluate the investment from an economic point of view, a model of sensitivity analysis is created and described and its outputs are presented and discussed at the end of the thesis.

This thesis deals with issues of smart houses and smart buildings. In the first part there is a research of possible systems installed in smart house. Each system is described from the perspective of its function and importance .The second part is focused on energy demands and where there is described European standard EN 15232 (Energy demand of building – influence of control automation and house management). In the practical part there was created scheme with devices which can be equipped smart houses with and their separation according to their relation to electricity. Each device is characterized by its electrical and nonelectrical parameters typical for family houses. Next part is about the proposal of prediction model of electricity consumption and generation. There are also stated quantities needed for prediction model and then method for prediction model realization.

No description available.

This diploma thesis is devoted to a rainwater management in commercial and administrative buildings. The goal of this work is to describe rainwater management system with a focus on its later usage. The work is divided into theoretical and practical parts. The first part examines the binding conditions, as well as the individual technologies and devices that must be included in the implementation of a rainwater management system. The practical part of the work is an analysis of the possibility of using rainwater for the needs of the fire brigade in Havlíčkův Brod. The result of this work is a calculation of the approximate payback period of the proposed system.

Allgemeine Gleichgewichtsmodelle (Computable General Equilibrium (CGE) models) werden oft genutzt, um Erkenntnisse über die gesamtwirtschaftlichen Auswirkungen bildungspolitischer Maßnahmen zu gewinnen. Eine Literaturrecherche zur Integration des Bildungs- und Ausbildungssystems in CGE-Modellen zeigt klare Limitationen bisheriger Studien bezüglich der Darstellung des Bildungs- und Ausbildungssystems und identifiziert damit eine wichtige Forschungslücke, der sich diese Dissertation widmet. Vor diesem Hintergrund ist das Hauptziel dieser Dissertation die Entwicklung eines neuartigen Ansatzes zur Einbeziehung der anerkannten Bildungs- und Berufsbildungssysteme in CGE-Modellen, einschließlich aller potenziellen Verbindungen zwischen diesen beiden Systemen. Das entwickelte Modell ermöglicht die Akkumulation von Arbeitskräften entsprechend der Veränderungen der Anzahl der Absolventen und Schulabbrecher eines integrierten Bildungs- und Ausbildungssystems. Es handelt sich um ein rekursiv-dynamisches Ein-Land-CGE-Modell (STAGE-Edu), das die mittel- bis langfristigen gesamtwirtschaftlichen Effekte verschiedener Bildungs- und Ausbildungspolitiken abbildet. Der Sudan gehört zu den Ländern der unteren mittleren Einkommensklasse, die bezüglich der Förderung der menschlichen Entwicklung vor zahlreichen Herausforderungen stehen. Aus diesem Grund werden in der vorliegenden Dissertation verschiedene bildungspolitische Maßnahmen analysiert und deren Auswirkungen auf das Wirtschaftswachstum und die Humankapitalbildung im Sudan bewertet. Der entwickelte Modellierungsrahmen leistet einen wichtigen Beitrag zur gesamtwirtschaftlichen Darstellung der durch Bildung und Ausbildung bewirkten menschlichen Entwicklung sowie der drauf abzielenden politischen Maßnahmen. STAGE-Edu bietet politischen Entscheidungsträgern ex-ante Erkenntnisse bezüglich der potenziellen Auswirkungen von Maßnahmen zur Verbesserung der Arbeitsqualifikation und letztlich zur Erhöhung des Lebensstandards der Bevölkerung. / Computable General Equilibrium (CGE) models have been widely used to generate insights into the economy-wide implications of education policy measures. A literature review on incorporating the education and training system in CGE models reveals explicit limitations of previous studies depicting vocational education and training system, hence, identifying a significant research gap, which shall be addressed in this dissertation. Against this background, the main objective of this dissertation is to develop a novel approach to incorporate the acknowledged education and vocational training systems in CGE models, including all potential exiting bridges between these two systems. The developed model enables labor force accumulation according to changes in the number of graduates and dropouts from an integrated education and training system. It is a recursive-dynamic single-country CGE model (STAGE-Edu), which depicts the medium- to long-run economy-wide effects of various education and training policies. The Sudan is one of the lower-middle-income countries that face numerous challenges in accelerating human development. For this reason, in the dissertation at hand different education and training policy measures are analyzed and their implications on economic growth and human capital accumulation in the Sudan are assessed. The developed modeling framework contributes to the field of economy-wide depiction of human development triggered by education and training as well as related policy measures. STAGE-Edu provides policymakers with ex-ante insights on potential impacts of measures for enhancing labor skills and ultimately for improving the livelihood of the population.

Les terres rares (TRs) sont des métaux stratégiques du XXIe siècle dont la demande croissante résulte de leurs propriétés essentielles, notamment dans les domaines des énergies renouvelables, de la médecine et des hautes technologies. Ils sont classés en TR lourdes (HTRs), terres légères légères (LTRs) et non-lanthanides. Leur dissémination dans l'environnement, associée à une faible recyclabilité, fait des TRs des contaminants émergents pour lesquels les études de toxicité sont jusqu'à présent très disparates. Afin d’établir une base générale de la réponse cellulaire et moléculaire à un stress TRs, nous avons premièrement utilisé des stratégies complémentaires et à haut débit pour étudier la réponse, ainsi que l’absorption des TRs chez le modèle eucaryote Saccharomyces cerevisiae. Les deletome, transcriptome, protéome et ionome de la levure ont été analysés et approfondis par des analyses physiologiques ciblées. Bien que des réponses communes aux TRs et à d'autres métaux aient été mises en évidence, les réponses spécifiques aux TRs étaient prédominantes. La composition de la paroi cellulaire, la biosynthèse des sphingolipides, la voie ESCRT et l'endocytose sont des éléments clés de la réponse aux TRs. Deuxièmement, nous avons exploré les effets des TRs sur le transcriptome et le ionome du modèle végétal Arabidopsis thaliana. L'exposition des TRs a négativement impacté l'architecture racinaire, comme l'a révélé la modulation de gènes liés à l'auxine. De plus, le ionome a été modifié et les gènes liés à une carence en Fe largement représentés parmi les gènes les plus différentiellement exprimés. Afin d'identifier de nouvelles plantes modèles accumulant des TRs, des espèces de Phytolacca et de fougères ont été criblées. Malgré un trait d’accumulation des TRs conservé chez quelques genres de fougères et Phytolacca, un enrichissement en HTRs chez Phytolacca et en LTRs chez les fougères a été observé. Cependant, plusieurs espèces de Dryopteris présentent des teneurs contrastées en TRs dans les frondes et représentent de nouveaux modèles pertinents pour décrypter les mécanismes d’accumulation et de tolérance aux TRs. Globalement, des divergences ont été mises en évidence dans la réponse aux différentes TRs, en fonction de leur rayon ionique. La composition de la paroi cellulaire, la détoxification vacuolaire, mais aussi l’accumulation et le fractionnement des TRs ont souligné ces différences. Nous avons confirmé que les LTRs empruntaient les canaux calciques, tandis que de nouvelles preuves ont été données sur le rôle des transporteurs de Fe dans l'accumulation de HTRs. En conclusion, nous apportons ici de nouveaux éléments sur la toxicité et les spécificités des TRs, ainsi que des explications moléculaires pour certains effets déjà connus. Ce travail constitue un premier travail de base complet et multi-approches pour de futures études afin d’approfondir la compréhension de la toxicité des TRs chez les organismes vivants. / Rare earth elements (REEs) are strategic metals whose demand in the 21st century is increasing as a result of their essential properties useful to the fields of renewable energies, medicine, and high-technologies. They are classified as heavy REEs (HREEs), light REEs (LREEs) and non-lanthanides. Their dissemination in the environment, together with poor recyclability, leads REEs to be considered emerging contaminants, for which toxicity studies are currently very fragmented. To build a strong general foundation on the cellular and molecular response to REEs, we first adopted high-throughput and complementary strategies to study the REE stress response and their uptake in the unicellular eukaryotic model Saccharomyces cerevisiae. The deletome, transcriptome, proteome and ionome of yeast were analysed together with in-depth physiological experiments. Although common responses between REEs and other metals were highlighted, REE-specific responses were predominant. Cell wall composition, sphingolipid biosynthesis, the ESCRT pathway and endocytosis were emphasized as key elements in the cellular response to REEs. Second, we explored how REEs affect the transcriptome and ionome of the plant model Arabidopsis thaliana. REE exposure negatively affected the root architecture, as revealed by the modulation of auxin-related genes. REEs impaired the ionome, and Fe deficiency-related genes were largely represented among the most differentially expressed genes in both roots and leaves. Additionally, to identify new REE-accumulating plant models, collections of ferns and Phytolacca species were screened. Despite a conserved REE accumulation trait for Phytolacca and a few fern genera, HREE enrichment was observed in Phytolacca, while LREEs were preferentially transferred into the fronds of all fern species. However, several Dryopteris species harboured contrasting REE contents in the fronds. The latter species will be of great importance in deciphering the mechanisms of REE accumulation and tolerance. Overall, the response towards REEs differed according to their ionic radius. The cell wall composition, vacuolar detoxification, and the accumulation and fractionation of REEs notably accounted for these differences. Our findings support LREE-mediated entry through calcium channels, while new evidence was provided for the role of Fe transporters in the accumulation of HREEs. In conclusion, we have provided new insights into REE toxicity and specificities, together with the molecular elucidation of REE effects that have not previously been mechanistically explained. This work is a first multi-approach comprehensive groundwork that will be used for future studies to deepen the understanding and assessment of REE toxicity in organisms.

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal. / Thèse de doctorat effectuée en cotutelle au Département de Géographie Université de Montréal et à l'Institut Méditerranéen d'Écologie et de Paléoécologie Université de Droit, d'Économie et de Sciences d'Aix-Marseille 111 / La tourbière de Mirabel (basses terres du St-Laurent, Québec méridional) a été étudiée dans le but de préciser l'influence exercée par les différents paramètres autogènes et allogènes sur l'accumulation postglaciaire du carbone. (l) Les dynamiques végétales régionales révèlent un contrôle climatique général, modulé localement par le contexte paléogéographique, la physiographie et les processus écologiques. (2) L'histoire postglaciaire du climat régional fut reconstituée par la méthode des analogues modernes, contrainte par les fluctuations du niveau du lac Hertel (Mont St-Hilaire). Les résultats obtenus témoignent d'un important réchauffement entre 13 000 et 11 000 cal. BP, d'un optimum thermique autour de 8000 cal. BP, et de deux périodes sèches (10 000-6500 et 5000-3000 cal. BP). (3) Les dynamiques postglaciaires internes de la tourbière furent indépendamment reconstituées en trois dimensions par l'analyse pluridisciplinaire de sept profils. Ces derniers montrent des successions végétales similaires, conformes au modèle de terrestrialisation, mais asynchrones. Ils témoignent en outre de conditions de surface très humides avant 6700 cal. BP, suivies de nombreuses fluctuations asynchrones sur l'ensemble du site. L'accumulation du carbone présente en revanche des tendances similaires dans tous les profils, caractérisées par de fortes accumulations avant 6200 cal. BP (moyennes de 7.1 à 19.1 gC.m .an'1) et de faibles accumulations depuis (moyennes de 2.7 à 6.3 gC.m'2.an ). (4) Les différentes conditions postglaciaires du développement de la tourbière sont confrontées. L'accumulation du carbone paraît avoir été essentiellement contrôlée par les interrelations entre la physiographie (alimentation minérotrophe initiale) et les processus autogènes, qui ont progressivement isolé la végétation tourbigène de la nappe phréatique. Notamment, ni le climat, ni les feux ne semblent avoir joué de rôle significatif. / Mirabel bog (St. Lawrence lowlands, southern Quebec) was studied with the aim to specify the influences exerted by the different autogenic and allogenic parameters on postglacial carbon accumulation. (1) Regional vegetation dynamics reveal a general climatic control, locally modified by the palaeogeographical context, physiography and ecological processes. (2) The postglacial history of the regional climate was reconstructed by the modem analogues method, constrained by the water level fluctuations of Lac Hertel (Mont St- Hilaire). Obtained results provide evidence for an important climate improvement between 13 000 and 11 000 cal. BP, a thermal optimum around 8000 cal. BP and two dry periods (10000-6500 and 5000-3000 cal. BP). (3) Postglacial internal dynamics were independently reconstmcted in three dimensions by the multidisciplinary analysis of seven profiles. They show similar plant successions, conforming to the terrestrialisation model but were asynchronous. They moreover attest the occurrence of very humid conditions prior to 6700 cal. BP, followed by numerous asynchronous fluctuations throughout the site. By contrast, carbon accumulation presents similar trends in all proiïles, characterised by high accumulation rates prior to 6200 cal. BP (averages from 7.1 to 19.1 gC.m .year ) and low rates since this date (averages from 2.7 to 6.3 gC.m'2.year-l). (4) The different postglacial conditions of peatland development arc coirfronted. Carbon accumulation appears to have been essentially controlled by the interplay between physiography (initial minerotrophic supply) and autogenic processes, which progressively isolated the peat-forming vegetation from groundwater. Notably, neither climate nor fire seem to have played a significant role.

Most known drug targets and metabolizing enzymes are located inside cells. Interactions with these proteins are determined by intracellular unbound drug concentrations. Assessing intracellular drug exposure is technically challenging, but essential for predicting pharmacokinetic, pharmacological, and toxicological profiles of new drugs. This thesis aims at establishing and applying a straightforward methodology to measure intracellular unbound drug concentrations. This was achieved by separately measuring cellular drug binding (fu,cell), and total intracellular drug accumulation (Kp). This allowed the calculation of intracellular drug bioavailability (Fic), which represents the fraction of the concentration added to the cells that is unbound in the cell interior. The methodology was initially developed in HEK293 cells, where the Fic of 189 drug-like compounds was measured. Binding to HEK293 cells was governed by compound lipophilicity and was correlated with binding to more complex systems, such as hepatocytes and brain. Due to negligible expression of drug transporters, Fic in this cell line was consistent with pH-dependent subcellular sequestration of lipophilic cations in low pH compartments. The methodology was then applied to study the effects of drug transporters on Fic. The uptake transporter OATP1B1 increased the Fic of its substrates in a concentration-dependent manner. In contrast, the Fic of P-gp substrates was decreased when P-gp was present. In human hepatocytes, the methodology allowed the determination of Fic without prior knowledge of transporter mechanisms or metabolic activity. Finally, the methodology was applied to measure the impact of Fic on target binding and cellular drug response. Intracellular concentrations of active metabolites of pro-drugs targeting the intracellular target thymidylate synthase were in agreement with the level of binding to this target. Further, high Fic was generally required for kinase and protease inhibitors to be active in cellular assays. In conclusion, the methodology can be used to predict if new drug candidates reach their intracellular targets in sufficient amounts. Furthermore, the methodology can improve in vitro predictions of drug clearance and drug-drug interactions, by measuring the drug available for intracellular enzymes. Finally, this work can be expanded to other xenobiotics, e.g., to predict their intracellular toxicity.

Thesis (MScAgric)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: The relationships between leaf and fruit represent a fundamental concept in perennial plants. This concept allows to understand and to manage, with regard to farming, the balance of a vine, which is important in terms of fruit quality (i.e. fruit composition), mainly when it comes to producing wines of different categories and styles. The understanding of vine structure, physiology and vine functioning ultimately allows for appropriate recommendations to be given with regard to farming procedures. These include the adaptation of the canopy architecture to achieve a certain yield per vine, the determination of an appropriate fruit microclimate as well as the prediction of harvest dates. One of the central notions of vine balance involves the relationship between the source and the sink organs. The definition of source-sink relationships incorporates several concepts, including the ability of a source tissue to produce carbohydrates through photosynthesis, the transport of these carbohydrates to various plant organs-tissues via appropriate transport channels, and the assimilation and storage of the carbohydrates in the sink organs. In past years, a number of simple ratios have been created to incorporate the relationship between source and sink organs and thereby define vine balance in order to aid in practical management decisions (choice of a training system, irrigation, canopy manipulation etc.). However, vine functioning is very complex and cannot be defined accurately by simple, static ratios. More integrated and dynamic physiological indicators of vine balance and functioning are needed in order to understand the complex communication between organs and ultimately improve on farming practices. In order to achieve this, a better grasp of source-sink relationships, including the signalisation between organs and the functioning of the transport tissues is required. A two year experiment was proposed to study the interaction between source and sink organs using a combination of both primary shoot girdling methods and berry classification according to size. Girdling removes the bark and phloem tissue, thereby interrupting carbon import as well as water flow to the bunch to a certain degree. The aim of the study was to demonstrate the complexity of vine functioning by investigating the dynamics of berry sugar and water accumulation (used as physiological indicators) and the influence thereof on berry fresh mass evolution. Furthermore, the use of berry sugar loading was proposed as an improved physiological indicator of vine balance as it is directly linked to source and sink functioning. Sugar production and the dynamics of berry sugar accumulation rely on photosynthesis which in turn is dependent on stomatal conductance and therefore also incorporates the effects of external abiotic factors (temperature, light and water). It furthermore gives a direct indication of sink functioning as it shows the progressive accumulation of sugar throughout the ripening period and the possible consequences on berry volume evolution. A primary shoot which bore two bunches was used to represent a biological replicate. The lower bunches were girdled above and below in order to completely isolate them from any carbohydrate import. These bunches, along with the upper ungirdled bunches and two control bunches from another shoot were sampled. The berries from these bunches were classified according to diameter, thereby providing the unique opportunity to study berries of the same volume/size. Measurements were done to determine the fresh and dry masses of the sampled berries, as well as to analyse the concomitant sugar concentrations. It was found that girdling clearly had an effect on berry sugar dynamics and the method was improved in the second year of the trial. Girdling in interaction with berry classification according to diameter demonstrated that berries from the same size could have different sugar concentrations. It further showed that, to a certain degree, a relationship exists between the first rapid phase of sugar accumulation and the post véraison increase in berry fresh mass, until the plateau of fruit sugar accumulation, which generally occurs around a sugar concentration of 20 Brix. Additionally, and more importantly, it was found that vine functioning and the balance between the source and the sink organs may be controlled to a certain degree. There is a strong degree of compensation within a vine which results from signalling between and within organs. When taking the results of this study into consideration, it becomes clear that the classical ratios used to quantify the complex relationships between the fruit and the leaves may not be completely adequate to do so. The current way of looking at source-sink relationships and thereby determining whether a vine is balanced or not is over-simplified and there are numerous limitations involved in this approach. The vine is far more complex and various aspects must be taken into consideration before any claims can be made concerning source-sink relationships and consequently leaf to fruit balance. / AFRIKAANSE OPSOMMING: Die verhoudings tussen blaar en vrug verteenwoordig ‘n fundamentele konsep in meerjarige plante. Begrip van hierdie konsep maak dit moontlik om in boerdery die balans van ‘n wingerdstok te verstaan en bestuur. Hierdie wingerdbalans is belangrik in terme van vrugkwaliteit (d.w.s. vrugsamestelling), hoofsaaklik met betrekking tot die produksie van wyne van verskillende kategorieë en style. Begrip van die wingerdstok se struktuur, fisiologie en funksionering maak dit moontlik om gepaste aanbevelings te maak rakende boerdery prosedures. Dit sluit in die aanpassing van die lower argitektuur om ‘n sekere opbrengs per wingerdstok te verkry, die vasstel van ‘n geskikte vrug mikroklimaat asook die voorspelling van oesdatums. Een van die sentrale denkwyses rondom wingerdstok funksionering behels die die bron-vragpunt verhouding. Die definisie van bron-vragpunt verhoudings inkorporeer verskeie konsepte, insluitende die vermoë van ‘n bronweefsel om koolhidrate te produseer deur fotosintese, die vervoer van hierdie koolhidrate na verskeie plantorgaan weefsels via die gepaste vervoerkanale asook die opname en berging van hierdie koolhidrate in die vragpunt organe. In die verlede is ‘n aantal eenvoudige verhoudings geskep om die verband tussen die bron en vragpunt organe te beskryf en sodoende die wingerdstokbalans te definieer met die doel om ondersteuning te bied in praktiese bestuursbesluite (die keuse van opleistelsel, besproeiing, lowermanipulasie, ens.). Wingerdstok funksionering is egter baie kompleks en kan nie akkuraat gedefinieer word deur eenvoudige, statiese verhoudings nie. Meer geïntegreerde en dinamiese fisiologiese aanwysers van wingerdstokbalans en funksionering is nodig om die komplekse kommunikasie tussen organe te verstaan en uiteindelik boerdery praktyke te verbeter. Om dit te bereik is ‘n beter begrip van bron-vragpunt verhoudings asook die seinoordrag tussen organe en die werking van die vervoerweefsels nodig. ‘n Twee jaar lange eksperiment is voorgestel om die interaksie tussen bron- en benuttingsorgane te ondersoek deur gebruik te maak van beide die primêre loot ringelering metode en korrel klassifikasie volgens grootte. Ringelering verwyder die bas en floëem weefsel en onderbreek sodoende koolstof invoer sowel as watertoevoer na die tros tot ‘n sekere mate. Die doel van die studie was om die kompleksiteit van wingerdstok funksionering aan te toon deur die dinamika van suiker en water akkumulasie in die korrel te ondersoek asook die invloed daarvan op korrel vars massa ontwikkeling. Verder is die gebruik van korrel suikerlading voorgestel as ‘n beter fisiologiese aanduiding van wingerdstok funksionering aangesien dit direk geassosieer is met bron-vragpunt funksionering. Suikerproduksie en die dinamika van suiker akkumulasie in die korrel berus op fotosintese wat weer afhanklik is van stomatale geleiding en daarom ook die effek van eksterne abiotiese faktore (temperatuur, lig en water) inkorporeer. Dit gee verder ‘n direkte aanduiding van die funksionering van die vragpunt organe omdat dit die progressiewe akkumulasie van suiker gedurende die rypwordingsperiode aantoon, asook die moontlike gevolge op korrelvolume ontwikkeling. ‘n Primêre loot wat twee trosse dra is gebruik om ‘n biologiese herhaling te verteenwoordig. Die laer trosse is bo en onder geringeleer om hulle heeltemal te isoleer van enige koolhidraat invoer. Hierdie trosse, tesame met boonste ongeringeleerde trosse en twee kontrole trosse vanaf ‘n ander loot is gemonster. Die korrels van hierdie trosse is geklassifiseer volgens hulle deursnee, om sodoende die unieke moontlikheid daar te stel om korrels van dieselfde volume/ grootte te bestudeer. Metings is gedoen om die vars en droë massas van die gemonsterde korrels te bepaal, asook om die gepaardgaande suikerkonsentrasies te analiseer. Daar is gevind dat ringelering duidelik ‘n effek gehad het op korrelsuiker dinamika en die metode is verbeter in die tweede jaar van die proef. Ringelering in wisselwerking met korrel klassifikasie volgens korrel deursnee het aangetoon dat korrels met dieselfde grootte verskillende suikerkonsentrasies kon hê. Dit het verder aangedui dat daar, tot ‘n sekere mate, ‘n verhouding bestaan tussen die vinnige fase van suiker akkumulasie en die na-véraison toename in korrel vars massa, totdat die plato in suiker akkumulasie bereik word, gewoonlik rondom ‘n suikerkonsentrasie van 20 Brix. Daarbenewens, en van groter belang, is gevind dat wingerdstok funksionering en die balans tussen die bron en vragpunt organe onder ‘n mate van beheer is. Daar is ‘n sterk mate van kompensasie binne ‘n wingerdstok wat die gevolg is van seinoordrag tussen en binne organe in die wingerdstok. Wanneer die resultate van hierdie studie in aanmerking geneem word, word dit duidelik dat die klassieke verhoudings, wat gebruik word om wingerdstok funksionering en balans mee te bepaal, moontlik nie beduidend betekenisvol is nie. Die wyse waarop bron-vragpunt verhoudings tans beskou word is, tot ‘n mate, ‘n oorvereenvoudiging en daar is heelwat beperkinge betrokke by hierdie benadering. Die wingerd is baie meer kompleks en verskeie aspekte moet in aanmerking geneem word voordat enige bewering gemaak kan word rakende bron-vragpunt verhoudings. / The University of Stellenbosch and Winetech for financial support