Plant growth and development is largely controlled in regions of totipotential cells around the plant body called meristems. The well characterized shoot and root apical meristems are responsible for vertical growth, in which many key players have been well studied. Lateral (secondary) growth is controlled by the vascular and cork cambiums, which are much less understood. A rapid growth of interest in a new model angiosperm tree, poplar, has facilitated the study of the two cambiums, specifically into their regulation at the genomic and proteomic levels. This study describes recent work carried out to explore the genetic regulation of secondary growth in poplar. Two genes have been identified that were previously not associated with the process of secondary growth. The first, a gene lacking annotation (FM#2), was identified through the investigation of a mutant from an activation-tagged population of poplar. This mutant showed aberrant secondary growth, with an increase in the phloem:xylem ratio. It also developed a thick, rough bark, and was subsequently named corky. Constructs to recapitulate this phenotype have been produced to allow the link between the gene FM#2 and the corky phenotype to be firmly established. The second gene was identified through a reverse genetics strategy to test if the Arabidopsis shoot apical meristem regulator, CLAVATA1 also played a role in the regulation of the vascular cambium. When it was downregulated in Arabidopsis, a significant increase in secondary growth was observed. Antisense and hairpin-RNAi constructs were produced to attempt downregulation of the gene in poplar using both traditional Agrobacterium-mediated transformations, and the recently developed strategy of induced somatic sector analysis. / Thesis (Master, Biology) -- Queen's University, 2008-09-23 16:35:26.603

Made available in DSpace on 2014-06-11T19:26:40Z (GMT). No. of bitstreams: 0 Previous issue date: 2005-08-26Bitstream added on 2014-06-13T20:34:26Z : No. of bitstreams: 1 lima_cp_me_botfca.pdf: 904449 bytes, checksum: 0df808d843a75f5c5a193dce30f8b1ab (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Conduziu-se dois experimentos, um em ambiente protegido e outro em campo, com o objetivo de avaliar a viabilidade do monitoramento da adubação nitrogenada em cobertura, na cultura do alho vernalizado, através de medidas indiretas do teor de clorofila nas folhas, relacionando-as com o estado nutricional das plantas. Foi adotado o delineamento experimental de blocos ao acaso e os resultados foram submetidos à análise de variância através de regressão, adaptando a melhor equação, através do programa Sisvar, versão 4.2. Os tratamentos utilizados foram: 0, 20, 40, 60, 120, 240 e 360 kg N ha-1, aplicados parceladamente em cobertura aos 30 e 50 dias após a emergência (DAE), tendo sido aplicado 20 t ha-1 de esterco bovino no plantio. Foram realizadas nove avaliações do teor de clorofila e altura das plantas com intervalos de 10 dias entre cada avaliação, iniciando-se aos 20 e finalizando aos 100 DAE. Por ocasião de cada avaliação, foram coletadas duas plantas para análise do conteúdo de nitrogênio e demais nutrientes. Na colheita, após o período de cura, foram obtidos os dados de produção de bulbos, porcentagem de bulbos pseudoperfilhados, índice de formato de bulbos e classificação de acordo com o tamanho. No experimento realizado em campo ocorreu interação entre as doses de nitrogênio e as épocas de avaliação para altura e teor de clorofila. Os maiores valores de altura foram encontrados sem aplicação de nitrogênio e nas épocas mais tardias de avaliações. Os maiores teores de clorofila foram encontrados quando se aplicou a dose de 240 kg ha-1 de nitrogênio, para as épocas avaliadas a maior concentração foi encontrada aos 100 DAE. A concentração de nitrogênio foi influenciada pelas doses e pelas épocas de avaliações, ocorrendo interação entre esses fatores... / Two experiments were carried out, one in a protected environment and another in the field, aiming to evaluate the viability of the sidedress nitrogen management in the vernalizated garlic culture, through indirect measures of the chlorophyll rate in the leaves, relating them with the nutritional state of the plants. The randomized block experimental design was adopted and the results were submitted to Analysis of variance through regression, adapting the best equation through Sisvar program, 4.2 version. The treatments used were: 0, 20, 40, 60, 120, 240 and 360 Kg N ha?£, applied in parts sisedress at 30 and 50 days after emergency (DAE), 20 t ha?£ of bovine manure during planting had been applied. Nine evaluations of the chlorophyll rate and plants height were carried out with 10 days intervals between each evaluation, beginning at 20 and ending at 100 DAE. In each evaluation two plants were collected for nitrogen rates analysis and other nutrients. At harvest, after the cure period, the production bulb data were obtained, secondary growth bulbs percentage, bulb formation index and classification according to the size. In the experiment carried out in the field there was interaction between the nitrogen dose and the dates of height evaluation and chlorophyll rate. The highest values of height were found without nitrogen application and in the latest evaluations. The highest chlorophyll rates were found when 240 Kg ha?£ of nitrogen were applied, for the dates evaluated the highest concentration occurred at 100 DAE. The nitrogen concentration was influenced by doses and dates of evaluation, with interaction between these factors...(Complete abstract click electronic access below)

Different kinds of nanoparticles are widely used in optoelectronic and photovoltaic applications to harvest light to increase efficiency of devices. ETS-10, which is a synthetic microporous material consisting of &ndash / Ti-O-Ti-O-Ti- wires that run in the crystal in a and b directions, has been of interest in such applications due to its unique properties. In the current study, the synthesis conditions of ETS-10 were investigated in order to obtain pure ETS-10 crystals with the desired morphology. For this purpose, ETS-10 crystals were synthesized using different molar compositions. The effects of several synthesis parameters on the obtained products were investigated. Furthermore, ETS-10 thin films were prepared on ITO glass substrates using secondary growth of ETS-10 for the first time. The orientation of the -Ti-O-Ti-O-Ti- wires inside ETS-10 were explored by preparing several ETS-10 films on the ITO glass substrates using secondary growth of ETS-10 multilayers with a partial a(b)-out-of-plane preferred crystal orientation. This orientation can be desirable for the advanced applications of ETS-10 films. Afterwards, silver nanoparticle modified ETS-10 crystals were prepared and characterized in detail to understand the interaction of silver nanoparticles with the synthesized ETS-10 crystals. For this purpose, ETS-10 in the as-prepared and silver nanoparticle containing forms have been characterized using, XRD, ICP-OES, SEM, HR-TEM, N2 Adsorption, XPS, and UV/VIS spectroscopy. In order to investigate the optical properties of the silver modified ETS-10, transmittance-reflectance measurements were carried out. In general, it is believed that all steps necessary for the preparation of ETS-10 films and preliminary steps for investigating ETS-10 for future photovoltaic applications were determined.

Orientador: Leonardo Theodoro Büll / Banca: Rumy Goto / Banca: Takashi Muraoka / Resumo: Conduziu-se dois experimentos, um em ambiente protegido e outro em campo, com o objetivo de avaliar a viabilidade do monitoramento da adubação nitrogenada em cobertura, na cultura do alho vernalizado, através de medidas indiretas do teor de clorofila nas folhas, relacionando-as com o estado nutricional das plantas. Foi adotado o delineamento experimental de blocos ao acaso e os resultados foram submetidos à análise de variância através de regressão, adaptando a melhor equação, através do programa Sisvar, versão 4.2. Os tratamentos utilizados foram: 0, 20, 40, 60, 120, 240 e 360 kg N ha-1, aplicados parceladamente em cobertura aos 30 e 50 dias após a emergência (DAE), tendo sido aplicado 20 t ha-1 de esterco bovino no plantio. Foram realizadas nove avaliações do teor de clorofila e altura das plantas com intervalos de 10 dias entre cada avaliação, iniciando-se aos 20 e finalizando aos 100 DAE. Por ocasião de cada avaliação, foram coletadas duas plantas para análise do conteúdo de nitrogênio e demais nutrientes. Na colheita, após o período de "cura", foram obtidos os dados de produção de bulbos, porcentagem de bulbos pseudoperfilhados, índice de formato de bulbos e classificação de acordo com o tamanho. No experimento realizado em campo ocorreu interação entre as doses de nitrogênio e as épocas de avaliação para altura e teor de clorofila. Os maiores valores de altura foram encontrados sem aplicação de nitrogênio e nas épocas mais tardias de avaliações. Os maiores teores de clorofila foram encontrados quando se aplicou a dose de 240 kg ha-1 de nitrogênio, para as épocas avaliadas a maior concentração foi encontrada aos 100 DAE. A concentração de nitrogênio foi influenciada pelas doses e pelas épocas de avaliações, ocorrendo interação entre esses fatores...(Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Two experiments were carried out, one in a protected environment and another in the field, aiming to evaluate the viability of the sidedress nitrogen management in the vernalizated garlic culture, through indirect measures of the chlorophyll rate in the leaves, relating them with the nutritional state of the plants. The randomized block experimental design was adopted and the results were submitted to Analysis of variance through regression, adapting the best equation through Sisvar program, 4.2 version. The treatments used were: 0, 20, 40, 60, 120, 240 and 360 Kg N ha?£, applied in parts sisedress at 30 and 50 days after emergency (DAE), 20 t ha?£ of bovine manure during planting had been applied. Nine evaluations of the chlorophyll rate and plants height were carried out with 10 days intervals between each evaluation, beginning at 20 and ending at 100 DAE. In each evaluation two plants were collected for nitrogen rates analysis and other nutrients. At harvest, after the "cure " period, the production bulb data were obtained, secondary growth bulbs percentage, bulb formation index and classification according to the size. In the experiment carried out in the field there was interaction between the nitrogen dose and the dates of height evaluation and chlorophyll rate. The highest values of height were found without nitrogen application and in the latest evaluations. The highest chlorophyll rates were found when 240 Kg ha?£ of nitrogen were applied, for the dates evaluated the highest concentration occurred at 100 DAE. The nitrogen concentration was influenced by doses and dates of evaluation, with interaction between these factors...(Complete abstract click electronic access below) / Mestre

The blue crab, Callinectes sapidus Rathbun, 1896, was studied because of its high dollar value to Florida's commercial and recreational fisheries. The purpose of this study was to describe the structure of the ovary and oogenesis in the blue crab and the morphological changes in the female reproductive developmental stages over time. Histological techniques for high-resolution light microscopy were used to determine sexual maturity of female blue crabs. The ovarian morphology, oogenesis, and changes through the annual reproductive cycle of blue crabs in Tampa Bay were investigated for a period of two years, from January 2005 to January 2007. Ovarian structure was assessed by analyzing histological sections embedded in plastic epoxy resin, which provided a higher resolution than any other embedding material previously used in research on blue crab reproduction. Qualitative analyses of female gonads were made by describing the structure of the oocytes and determining the developmental stage of the oocytes from oogonia to full-grown oocytes. This study developed and introduced a new reproductive staging criteria for the species. Morphological characteristics of ovarian tissues and oocytes were determined to develop a classification for oocyte maturation stages. Morphological changes in the oocytes are well defined, and these were used to develop the staging schema. In this study, it was found that carapace width is not a good indicator of maturity or developmental stage. Examination of the annual reproductive cycle indicates that late secondary growth occurs from July to March, and gravid crabs were found during November and December. Histological examination of ovarian tissue is essential for determining maturity in female blue crabs. By observing ovarian characteristics and by establishing the length of secondary growth during oogenesis in blue crabs of Tampa Bay, a more thorough understanding of the cyclic reproductive aspects of this species was obtained and specifically that animals at a carapace width between 100 mm and 125 mm may have mature oocytes, yet external features may not indicate that they are mature.

Made available in DSpace on 2014-06-11T19:26:40Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-06-19Bitstream added on 2014-06-13T19:13:47Z : No. of bitstreams: 1 fernandes_ljc_me_botfca.pdf: 381482 bytes, checksum: e32cf2712ac5f36fe4ffd164adeb9b78 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Foram desenvolvidos dois experimentos com o objetivo de avaliar o crescimento, estado nutricional e produtividade de plantas de alho livres de vírus, em função de doses crescentes de nitrogênio. Os tratamentos foram 0, 20, 40, 80, 160, e 320 kg N ha-1, utilizando, como fonte, nitrato de amônio. Foi utilizada a cultivar Caçador L. V. (livre de vírus), os bulbilhos foram obtidos mediante cultura de tecido e termoterapia no Departamento de Produção Vegetal – Defesa Fitossanitária FCA / UNESP, multiplicados por quatro gerações em telado, no município de Guarapuava - PR. No experimento I, conduzido no município de Guarapuava – PR, foi utilizado o delineamento experimental de blocos ao acaso, com cinco repetições, com doses aplicadas em cobertura, na proporção de 20% da dose, quando as plantas apresentavam de 5 a 6 folhas; 30% quando apresentavam de 7 a 8 folhas; e 50% após a fase de diferenciação dos bulbos. A colheita ocorreu 149 dias após o plantio. O experimento II foi conduzido no município de Santa Juliana – MG, utilizando o delineamento de blocos ao acaso, com seis repetições, com doses aplicadas em cobertura, na proporção de 25% da dose, quando as plantas apresentavam de 3 a 4 folhas; 25% com 5 a 6 folhas; e 50% após a fase de diferenciação dos bulbos. A colheita ocorreu 112 dias após o plantio. As doses crescentes de N não influenciaram o crescimento das plantas, a média do comprimento na diferenciação foi de 92,8 cm para o experimento I e de 88,9 cm para o experimento II. Os valores do índice relativo de clorofila (IRC) foram aumentados com a elevação das doses de N apenas na fase de diferenciação e 15 dias após, para ambos os experimentos. Em relação aos teores foliares dos macronutrientes, no experimento I as doses de N influenciaram na absorção de N, K e S; já no experimento II, na absorção de N e na diminuição da absorção... / Two experiments were developed with the objective to evaluate the growth, plant nutrition and productivity of garlic without virus, submitted to nitrogen fertilization. The treatments used were 0, 20, 40, 80, 160, and 320 kg N ha-1, using as source ammonium nitrate. The cultivar used was Caçador L.V. (free of virus), the cloves were gotten through tissue culture and thermotherapy in Vegetal Production Department - Plant Protection FCA/UNESP, multiplied for four generations in greenhouse environment in Guarapuava - PR city. The experiment I was developed in Guarapuava - PR city, the experimental delineation used was randomized blocks, with five repetitions, the doses were applied in covering, divided: 20% of the dose when the plants have 5 or 6 leaves, 30% when the plants have 7 or 8 leaves and 50%, after the bulbs differentiation, the harvest occurred 149 days after planting. The experiment II was developed in Saint Juliana - MG city, using randomized blocks delineation with six repetitions, the doses were applied in covering divided: 25% of the dose when the plants have 3 or 4 leaves, 25% when the plants have 5 or 6 leaves and 50%, after the bulbs differentiation, the harvest occurred 112 days after planting. The increasing doses of N had not influenced the growth of the plants, the average length of garlic plants at differentiation was 92,8 cm in the experiment I and 88,9 cm in the experiment II. The values of relative index of chlorophyll (IRC) were increased with the rise of the N doses only at differentiation and 15 days after, for both experiments. About macronutrients concentration in leaves, in experiment I the doses of N had influenced in N, K and S absorption, and in experiment II, in N absorption and in the reduction of the P, K and S absorption. The micronutrients absorption was influenced only in experiment II, for the nutrients B, Mn and Zn...(Complete abstract click electronic access below)

Un des enjeux majeurs des procédés membranaires concerne le développement de nouveaux matériaux de filtration stables dont les propriétés texturales et structurales permettent d'orienter la sélectivité des membranes de nanofiltration. En particulier, l'utilisation de matériaux zéoliihiques comme couche filtrante a montré qu'après un traitement chimique adéquat, ces matériaux pouvaient acquérir des propriétés de sélectivité très particulières. Ce travail de thèse propose la synthèse, la caractérisation et l'optimisation de membranes de nanofiltration tubulaires en utilisant une zéolithe de type MFI. Plus particulièrement, des films mono et bicouches de zéolithes de type MFI ont été préparés sur un support tubulaire macroporeux asymétrique en alumine. La diffraction de rayons X et la microscopie électronique à balayage ont permis de déterminer la cristallinité, l'homogénéité et l'épaisseur des filins déposés (7 à 15 i_trn). La manométrie d'adsorption d'azote a été utilisée pour vérifier si la porosité après mise en forme restait accessible, ainsi qu'à déterminer la niasse de zéolithe déposée sur le support tubulaire en alumine. La perméabilité hydraulique, qui caractérise l'hydrodynamique d'une membrane, a été déterminée par filtration d'eau déminéralisée. Cette étape dite « de conditionnement » est nécessaire pour parvenir à un état de performance stable de la membrane (état d'équilibre), La perméabilité hydraulique de la membrane mono et bicouche MFI diminue rapidement au début de la phase de conditionnement, et finit par se stabiliser au bout de 15 heures de filtration pour atteindre une valeur minimale de 1,08 x tem-2 et 1,02 x 10-15 m3.ni-2 respectivement. La sélectivité et les performances de filtration de ces membranes vis-à-vis de différents types de solutés (ioniques, molécules organiques, mélanges) ont été analysées à l'issue de la phase de conditionnement. Les résultats obtenus sont très encourageants, ils ont fait l'objet de plusieurs articles de recherche. / Zeolites are very well-known materials especially for their controlled porosity, their crystalline structures, but also for the different applications where they can be used (catalysis, air treatment,...) . During the past ten years, a lot of developments have been done on the preparation of zeolite membranes for pervaporation applications. The present work explores new developments in the preparation zeolite membranes dedicated to the filtration of salty water. More particularly, we prepared MFI films on specific macroporous alumina tubular supports used for nanofiltration applications. There are different key steps which influence the formation of the MFI films: the cleaning procedure of the substrats, the hydrothermal synthesis conditions, the use of a secondary growth method for when preparing a bi-layered membrane. A complete characterization of the mono and the bi-layered membranes was carried out using various techniques, such as X-ray diffraction, scanning electron microscopy, X-ray fluorescence, energy dispersive X-ray spectroscopy, mercury porosimetry and nitrogen sorption measurements. Results show that a dense, continuous and highly crystallized thin film of MFI bas been obtained on the u-alumina support after the secondary growth experiment. The weight of zeolite deposited on the support was also estimated by nitrogen sorption measurement using the method of mass assessment. The MFI membrane was stabilized by pure water filtration tests until the hydraulic permeability reached a plateau. This conditioning step was necessary to reach an equilibrium state of the hydraulic membrane performances. Particularly, hydration of the MFI layer was a crucial step of the conditioning process, which leads to the modification of the MFI surface properties. The hydraulic permeability of the mono and bi-layer MFI membrane decreased rapidly at the beginning of the conditioning process, and stabilized alter 15 hours to reach 1.08 x 10.141113.m.2 and 1.02 x 10-15 m3.m-2 respectively. Filtration tests were then carried out with a neutral molecule (VB 12) in order to evaluate the mean pore radius of the mono and the bi-layered membranes. A rejection rate of 5% was obtained with the monolayer MFI membrane, while it reaches a value of 50% with the bi-layered one. These results lead to mean pore radius corresponding to 6.4 and 1.7 mn respectively. It menus that even alter the synthesis of the second MFI layer, the membrane porosity remains higher than the porous diameter of the zeolite. Filtration may occur at the interface of the MFI crystals.

Resumo: Foram desenvolvidos dois experimentos com o objetivo de avaliar o crescimento, estado nutricional e produtividade de plantas de alho livres de vírus, em função de doses crescentes de nitrogênio. Os tratamentos foram 0, 20, 40, 80, 160, e 320 kg N ha-1, utilizando, como fonte, nitrato de amônio. Foi utilizada a cultivar Caçador L. V. (livre de vírus), os bulbilhos foram obtidos mediante cultura de tecido e termoterapia no Departamento de Produção Vegetal - Defesa Fitossanitária FCA / UNESP, multiplicados por quatro gerações em telado, no município de Guarapuava - PR. No experimento I, conduzido no município de Guarapuava - PR, foi utilizado o delineamento experimental de blocos ao acaso, com cinco repetições, com doses aplicadas em cobertura, na proporção de 20% da dose, quando as plantas apresentavam de 5 a 6 folhas; 30% quando apresentavam de 7 a 8 folhas; e 50% após a fase de diferenciação dos bulbos. A colheita ocorreu 149 dias após o plantio. O experimento II foi conduzido no município de Santa Juliana - MG, utilizando o delineamento de blocos ao acaso, com seis repetições, com doses aplicadas em cobertura, na proporção de 25% da dose, quando as plantas apresentavam de 3 a 4 folhas; 25% com 5 a 6 folhas; e 50% após a fase de diferenciação dos bulbos. A colheita ocorreu 112 dias após o plantio. As doses crescentes de N não influenciaram o crescimento das plantas, a média do comprimento na diferenciação foi de 92,8 cm para o experimento I e de 88,9 cm para o experimento II. Os valores do índice relativo de clorofila (IRC) foram aumentados com a elevação das doses de N apenas na fase de diferenciação e 15 dias após, para ambos os experimentos. Em relação aos teores foliares dos macronutrientes, no experimento I as doses de N influenciaram na absorção de N, K e S; já no experimento II, na absorção de N e na diminuição da absorção ...(Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Two experiments were developed with the objective to evaluate the growth, plant nutrition and productivity of garlic without virus, submitted to nitrogen fertilization. The treatments used were 0, 20, 40, 80, 160, and 320 kg N ha-1, using as source ammonium nitrate. The cultivar used was Caçador L.V. (free of virus), the cloves were gotten through tissue culture and thermotherapy in Vegetal Production Department - Plant Protection FCA/UNESP, multiplied for four generations in greenhouse environment in Guarapuava - PR city. The experiment I was developed in Guarapuava - PR city, the experimental delineation used was randomized blocks, with five repetitions, the doses were applied in covering, divided: 20% of the dose when the plants have 5 or 6 leaves, 30% when the plants have 7 or 8 leaves and 50%, after the bulbs differentiation, the harvest occurred 149 days after planting. The experiment II was developed in Saint Juliana - MG city, using randomized blocks delineation with six repetitions, the doses were applied in covering divided: 25% of the dose when the plants have 3 or 4 leaves, 25% when the plants have 5 or 6 leaves and 50%, after the bulbs differentiation, the harvest occurred 112 days after planting. The increasing doses of N had not influenced the growth of the plants, the average length of garlic plants at differentiation was 92,8 cm in the experiment I and 88,9 cm in the experiment II. The values of relative index of chlorophyll (IRC) were increased with the rise of the N doses only at differentiation and 15 days after, for both experiments. About macronutrients concentration in leaves, in experiment I the doses of N had influenced in N, K and S absorption, and in experiment II, in N absorption and in the reduction of the P, K and S absorption. The micronutrients absorption was influenced only in experiment II, for the nutrients B, Mn and Zn...(Complete abstract click electronic access below) / Orientador: Leonardo Theodoro Büll / Coorientador: Marcelo Agenor Pavan / Banca: Rosemary Marques de Almeida Bertani / Banca: Francisco Maximino Fernandes / Mestre

La croissance secondaire est à l'origine de l'accumulation de biomasse pérenne par les arbres et détermine en partie la capacité des écosystèmes forestiers à stocker du carbone. Cependant, les contraintes environnementales sur la croissance en milieu méditerranéen sont encore mal décrites et nous ne savons pas comment les changements climatiques futurs vont les modifier. L'objectif de la thèse est de déterminer, principalement à partir de l'étude de l'allocation du carbone à la croissance secondaire, les réponses fonctionnelles saisonnières et interannuelles du chêne vert (Quercus ilex L.) aux variations climatiques en région méditerranéenne. L'utilisation de différentes approches expérimentales, à des échelles spatiales allant du cerne à l'écosystème et à des échelles temporelles allant de la journée à plusieurs dizaines d'années, a permis de mettre en évidence l'effet de différentes contraintes environnementales (disponibilité en eau, réchauffement de la température, et densité du peuplement) sur la croissance secondaire et la composition isotopique du cerne. L'étude de la phénologie de la croissance montre que celle-ci est contrôlée directement par les températures hivernales et le déficit hydrique, plus que par la disponibilité en éléments carbonés issus de la photosynthèse. De 1968 à 2013, les changements climatiques ont entrainé une contrainte hydrique de plus en plus précoce qui s'est trouvée compensée par un début de croissance initié plus tôt dans l'année, sous l'effet du réchauffement des températures hivernales, et une meilleure efficacité d'utilisation de l'eau, sous l'effet de l'augmentation de la concentration en CO2 atmosphérique. La réduction de la mortalité et l'augmentation de la croissance observée dans des parcelles éclaircies montre que cette pratique sylvicole permet de préparer les taillis de chêne vert à l'intensification de la sècheresse prévue pour la région méditerranéenne. / Tree secondary growth is responsible for woody biomass accumulation and is a major component of carbon storage in forest ecosystems. Environmental constraints on secondary growth in Mediterranean ecosystems must, however, be described in more to details to better understand how they will be modified by climate change. This dissertation aims at studying the functional responses of Mediterranean holm oak (Quercus ilex) to seasonal and inter-annual climate variations through the study of carbon allocation to secondary growth. Different experimental approaches, at spatial scales ranging from tree rings to the ecosystem and at temporal scales from the day to several decades, were used to identify the main environmental constraints (water availability, temperature warming, competition) to secondary growth and carbon isotopic composition of tree rings. The phenology of stem growth shows evidence for a direct environmental control on annual growth by winter temperature and summer drought that is more limiting than the carbon supply from photosynthesis. Climate change from 1968 to 2013 resulted in earlier water limitation on secondary growth, which was compensated by earlier growth onset, due to warmer winter temperature, and higher water use efficiency, due to increased atmospheric CO2 concentration. Thinning reduced tree mortality and increased stem growth, so thinning management in old holm oak coppices could prepare the ecosystem to better withstand the increasing drought forecasted for the Mediterranean region.

Cacti (Cactaceae) represent a family of highly specialized angiosperm plants with a native range of distribution restricted to the American continents. Columnar cacti of the sub-family Cactoideae evolved in adaptation to their arid or semi-arid habitats characteristics that distinguish them from most other dicot plants, e.g. the stem succulence with a strongly vascularized storage parenchyma and the presence of the spine wearing areoles. Although cacti have been in cultivation since the discovery of America, some studies even suggest the agricultural use in pre-colombian times, and many scientific investigations were carried out on the functional morphology and anatomy with regard to biomechanical adaptations of the found structures, no research focused on the branch-stem attachment. The most conspicuous features of such a ramification are the pronounced constrictions at the branch-stem junctions that are also present in the lignified vascular structures within the succulent cortex. Based on Finite Element Analyses of ramification models it could be demonstrated that these indentations in the region of high flexural and torsional stresses are not regions of structural weakness, e.g. allowing vegetative propagation. On the contrary, they can be regarded as anatomical adaptations to increase the stability by fine-tuning the stress state and stress directions in the junction along prevalent fiber directions. The development of the woody support structure within the succulent cortex of the parental shoot can be traced back to the leaf and bud traces of the dormant axillary buds. Surprisingly, these initials also develop into another woody structure supporting the flowers of the cacti. As these two support structures differ significantly in their macroscopic and microscopic anatomy and as they develop from the same initial state as leaf/bud traces, another objective of this work was to analyze the secondary growth of the two structures with traditional botanic investigation methods. The results of these investigations reveal a wood dimorphism consisting of an early parenchymatous phase followed later by fibrous wood in both kind of support structure. In vegetative branches, the woody support structures have the typical ringlike arrangement as found in the stele of the parental shoot, whereas the flower support structures have a reticular arrangement of interconnected woody strands. This fundamentally different anatomy of the support structures results from the formation of an interfascicular cambium between the leaf/bud traces when a vegetative branch forms or its absence in the case of a flower. After shedding light on the functional morphology and anatomy of the cactus ramification and their development the question arises if the found load adaptation strategies may serve to improve technical fiber composite structures analogue to the design recommendation developed from the biomechanical analyses of tree ramifications. Such a biomimetic transfer from the cactus ramification as biological role model to a technical implementation and the adaptation of the fine-tuned geometric shape and arrangement of lignified strengthening tissues might contribute to the development of alternative concepts for branched fiber-reinforced composite structures within a limited design space.