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Lowering phenology and dormancy dynamics of apple tree in contrasting climatic conditions: a case study of phenology modeling in the climate warming contextMalagi, Gustavo 02 December 2014 (has links)
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Previous issue date: 2014-12-02 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Os padrões climáticos têm sofrido alterações em escala global nas últimas
décadas e consequências graves sobre o desenvolvimento de diversas espécies
vegetais têm sido observadas. A intensificação dos avanços fenológicos no hemisfério
norte tem despertado o interesse sobre a compreensão da fisiologia da dormência de
espécies temperadas quando submetidas a regimes de aquecimento. A proposta
desse estudo foi comparar os padrões regionais de temperatura e floração de
cultivares de macieiras cultivadas em climas contrastantes, a partir de uma extensa
base de dados de temperatura e fenologia. Assim, foi possível compreender como a
temperatura controla o processo de floração e diagnosticar as zonas de produção
mais vulneráveis ao aquecimento. Séries históricas de temperatura foram coletadas
na Europa Ocidental (inverno frio), Marrocos e no sul do Brasil (inverno quente). Datas
de ocorrência de dois estágios de floração e o tempo transcorrido entre eles foram
analisados. Verificou-se o aquecimento de todas as áreas da Europa Ocidental na
primavera, e um leve aquecimento do período invernal na zona sul dessa região.
Nesses locais os avanços das datas de floração e o curto tempo de floração ocorreram
pela elevação das temperaturas primaveris. A região sul mostrou-se mais vulnerável
a futuros aquecimentos. No Marrocos e sul do Brasil o aquecimento foi mínimo nas
últimas décadas sendo o inverno mais afetado. Leves mudanças fenológicas e longos
períodos de floração estiveram associados às temperaturas invernais. Padrões de
fenologia e temperatura intermediárias foram observados no Marrocos. Por outro lado,
estudo complementar foi conduzido no Brasil e na França visando compreender o
mecanismo de dormência da macieira, os fatores intrínsecos que a controlam, além
de analisar as variabilidades regionais e varietais. A cinética da dormência foi
determinada em gemas vegetativas por “One-bud cutting test” e em gemas florais por
“Tabuenca’s test”. Gemas vegetativas apresentaram dormência oscilante durante
outono-inverno-primavera na França, sendo profunda no inverno. No Brasil, as gemas
vegetativas apresentaram dormência com variações amenas no período equivalente
e com profundidade superficial. O aumento significativo do peso fresco e seco dos
primórdios florais caracterizou a fase transitória entre endo- e ecodormência. No
entanto, o estabelecimento da ecodormência esteve relacionado com o aumento
significativo do peso seco e da capacidade de reidratação dos primórdios florais. A
transição entre essas fases foi acelerada no Brasil e mais lenta na França. Ainda, a
partir de dados históricos de temperatura e fenologia, foram selecionados modelos
fenológicos sequenciais capazes de estimar regionalmente as datas anuais de
floração em ambos os hemisférios. Dois modelos foram validados para a estimação
do estágio de floração BBCH 61 (NHGoldenF1) e BBCH 65 (NHGoldenF2) de Golden
Delicious, na Europa Ocidental. Esses modelos apresentaram elevada acuracidade e
apresentaram eficiência superior aos modelos termais. Considerando um cenário RCP
de incremento intenso da temperatura até o final do século, observou-se tendência de
alongamento do período de acúmulo de frio, principalmente em Nîmes, e antecipação
das datas de floração em Angers, até o final desse século, segundo os dois modelos
NH. Em ambos os cenários e locais, observou-se redução significativa da fase de
ecodormência até o final desse século, com os menores valores registrados em
Nîmes. Essa perspectiva de mudanças na temperatura na região Mediterrânea da
Europa predispõe futuramente o alongamento do período de floração, resultando
distúrbios fisiológicos característicos de regiões de clima ameno hoje. Outros
conceitos de modelos ou a inclusão de múltiplos fatores durante a parametrização
devem ser considerados em um futuro breve, haja vista ainda, que o agravamento
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climático na Europa, poderá comprometer a aplicabilidade dos modelos sequências,
como se observou na atual situação climática do sul do Brasil. / Weather patterns have changed globally in recent decades causing serious
consequences on the development of several plant species. The intensification of
phenological advances in the northern hemisphere has raised interest in the
understanding of dormancy physiology in temperate species when subjected to
warming regimes. The purpose of this study was to compare regional patterns of
temperature on the flowering of apple tree cultivars grown under contrasting climates,
using an extensive database of temperature and phenology records. Thus, it was
possible to understand how temperature controls the flowering process and identify
the areas most vulnerable to warming. Historical temperature series collected for
Western Europe (cold winter), Morocco and Southern Brazil (warm winter) were used.
Historical dates of two flowering stages and the time between them were analyzed. All
areas in Western Europe experienced warming in the spring, whereas a slight warming
of winter was found in the mild areas. The observed advancement of blooming dates
and the short blooming time were linked to spring temperature increase in Western
Europe, with the southern region being more vulnerable to future warming. In Morocco
and Southern Brazil minimal warming was found in recent decades but winter was
most affected. Weak phenological changes and long flowering periods were
associated with winter temperatures. Phenology patterns and intermediate
temperatures were observed in Morocco. Moreover, an additional study was
conducted in Brazil and France to understand the mechanism of dormancy in apple
trees, the intrinsic factors that controls it, and to analyze the regional and varietal
variability. The kinetics of dormancy in vegetative buds was determined by a "One-bud
cutting test" and in floral buds by "Tabuenca's test." Vegetative buds showed
fluctuating dormancy during autumn-winter-spring in France, which was deeper in
winter. In Brazil, the vegetative buds showed weak variations and shallow depth in the
equivalent period. The significant increase in fresh and dry weight of flower primordia
characterized the transitional phase between endo- and ecodormancy. However,
ecodormancy establishment was related to the significant increase in dry weight of
floral primordia and their ability to rehydrate. The transition between these phases was
fast in Brazil and slower in France. Sequential models, able to estimate annual
blooming dates in both hemispheres were selected from historical temperature and
phenology data. Two models were validated to estimate the stages BBCH 61
(NHGoldenF1) and BBCH 65 (NHGoldenF2) of Golden Delicious in Western Europe.
These models showed high accuracy and greater efficiency in relation to thermal
models. Considering a CPR scenario of intense increase in temperature by the end of
this century, there was estimated a trend to extend the period of chill accumulation,
especially in Nîmes, and advance dates for flowering in Angers, by the end of this
century, according the two NH models. Under both scenarios and locations, there was
a significant reduction in the ecodormancy phase, with the lowest values recorded at
Nîmes. The projected changes in temperature in the mediterranean region of Europe
can extend the flowering period, resulting in physiologic disturbances as today in mild
climate. Other concepts of models and/or the inclusion of multiple factors in the model
should be considered in the near future, considering that warming in Europe may
compromise the applicability of the sequential models, as observed currently in
southern Brazil.
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Les effets des tannins condensés du sainfoin (Onobrychis viciifolia) sur sa digestion et sa valeur nutritiveTheodoridou, Katerina 17 December 2010 (has links) (PDF)
Résumé indisponible
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Communautés microbiennes de la baie de raisin : Incidence des facteurs biotiques et abiotiques / Microbial communities of the grappe berry : effect of biotic and abiotic factorsMarques Martins, Guilherme 03 July 2012 (has links)
L’étude des communautés microbiennes de la baie de raisin dans des conditions de production à l’échelle de la parcelle montre une dynamique temporelle des populations cultivables, qui se traduit par une augmentation des niveaux de population à partir des stades de début véraison et début maturité. Concernant la communauté bactérienne cultivable, 44 espèces appartenant à 21 genres ont été identifiées. Parmi les huit genres identifiés pour la population fongique, les espèces appartenant au genre Aureobasidium sont les plus abondantes, contrairement aux espèces fermentaires qui restent minoritaires. L’incidence des facteurs biotiques et abiotiques sur différents paramètres de population microbienne tels que la structure, la densité et l’activité métabolique a été analysée. Nous avons observé que les zones climatiques plus fraîches et humides, favorisent le développement des microorganismes. Ces travaux mettent en évidence l’impact écotoxique du cuivre sur la communauté microbienne, en particulier dans sa fraction bactérienne. Le développement de Botrytis cinerea sur la grappe modifie la communauté microbienne des baies de raisin sain : le nombre d’espèces bactériennes augmente ainsi que leur diversité. La communauté bactérienne de la baie de raisin est proche de celle des feuilles d’un point de vue de sa structure, et mais éloignée de celles des écorces et du sol, avec des indices de diversité et de richesse plus faibles. / The study of microbial communities associated with wine grapes under field conditions revealed changes in the size and structure during the berry ripening process, with levels rising gradually and reaching their highest value when the berries were over ripe. During this work several bacteria and fungi species, including fermentative yeast, have been isolated and identified. From cultured bacteria, over 44 species were identified from 21 genera. Concerning fungi population, among eight genera identified, the genus Aureobasidium was the most abundant. Our study reveals the impact of different abiotic and biotic factors over microbial community structure, density and metabolic activity. Comparing different vineyards in the same region, we observed that areas presenting more humid and colder climate favor the growth of microorganisms. Our results also show that the farming system has a clear impact on the microbial community, especially in the bacterial fraction. One of the reasons is the inhibiting effect of copper-based fungicides, frequently used in both organic and conventional farming systems. The presence of Botrytis cinerea in grape berries without visual symptoms of infection can change the microbial community of the grapes, increasing bacterial population density and diversity.
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Effet du changement climatique et de la phénologie de l’arbre hôte sur l’étendue spatiale des épidémies de la tordeuse des bourgeons de l’épinette : une approche à base d’agentsSauri Ramirez, Jennifer 01 1900 (has links)
Le changement climatique continue d'affecter la dynamique des paysages forestiers à grande échelle. Cependant, il demeure incertain comment ces changements affecteront les forêts futures et en particulier les épidémies des insectes ravageurs forestiers. Le changement climatique affecte l’émergence des insectes, en perturbant notamment la synchronisation phénologique entre les insectes herbivores et leurs arbres hôtes. De telles perturbations peuvent avoir des conséquences importantes sur le moment de l’émergence, l'étendue et la gravité de l'épidémie. Cette étude vise à comprendre comment le changement climatique pourrait affecter la synchronie phénologique entre la tordeuse des bourgeons de l'épinette (Choristoneura fumiferana), un défoliateur indigène, et ses espèces hôtes (Abies balsamea et Picea mariana) et comment cela pourrait affecter l'étendue des épidémies de la tordeuse des bourgeons de l'épinette dans la région de la Côte-Nord au Québec, Canada. Nous avons exploré les effets de deux facteurs expérimentaux sur l'étendue des épidémies à l'aide d'un modèle de simulation stochastique spatialement explicite à base d’agents (MBA): (1) la température quotidienne représentée selon deux niveaux d'augmentation (+2°C et +4°C) relative à une base de référence 2016 et (2) la variation de la phénologie des arbres hôtes correspondant aux différents niveaux d'incertitude (SD) concernant le moment du débourrement des bourgeons. Nous avons évalué comment ces facteurs ont affecté la variation de l'étendue des épidémies de la tordeuse des bourgeons de l'épinette et la complexité spatiale du patch épidémique sur un horizon de simulation de 20 ans. Nos résultats de simulation indiquent que la synchronisation phénologique arbres hôtes-insectes est fortement affectée par les changements de température, mais de manière non linéaire. Une augmentation de 2°C a permis de réduire l'étendue de l'épidémie en raison de la faible survie des larves, tandis qu'une augmentation de 4°C a entraîné une survie plus élevée des insectes et des épidémies plus importantes. Notre modèle peut aider à prévoir la dynamique future des forêts et faciliter l'élaboration de meilleures stratégies de gestion pour réduire l'effet des épidémies sur les paysages forestiers. / Climate change continues to affect forest landscape dynamics at a global scale. However, it remains uncertain how these changes will affect future forests and in particular outbreaks of forest insect pests. Climate change can affect outbreaking insects by disrupting phenological synchrony between herbivorous insects and their host trees. Such disruptions can have important consequences for outbreak timing, extent, and severity. This study aims to understand how climate change could affect the phenological synchrony between the spruce budworm (Choristoneura fumiferana), a native outbreaking defoliator, and its host trees (Abies balsamea and Picea mariana), and how this might affect the extent of spruce budworm outbreaks in the Côte-Nord region in Quebec, Canada. We explored the effects of two experimental factors on outbreak extent using a spatially explicit stochastic agent-based simulation model (ABM): (1) daily temperature represented as two levels of increase (+2°C and +4 °C) relative to a 2016 baseline, and (2) variation in host phenology represented as four different levels of uncertainty (SD) around the timing of budburst. We assessed how these factors affected variation in spruce budworm outbreak extent and outbreak patch spatial complexity over a 20-year simulation horizon. Our simulation results indicate that host trees-insect phenological synchrony is strongly affected by temperature changes, but in a non-linear way. An increase of 2°C was found to reduce outbreak extent due to poor larval survival, while an increase of 4°C resulted in higher insect survival and larger outbreaks. Our model can help to forecast future forest dynamics and facilitate the development of better management strategies to reduce the effect of outbreaks on forest landscapes.
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Les effets des tannins condensés du sainfoin (Onobrychis viciifolia) sur sa digestion et sa valeur nutritive / The effects of condensed tannins in sainfoin (Onobrychis viciifolia) on its digestion and nutritive valueTheodoridou, Katerina 17 December 2010 (has links)
Résumé indisponible / Résumé indisponible
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