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Previous issue date: 2011-11-01 === The growth and development of plants of the rosaceae family present variations of
physiological processes during the annual cycle. Plant species that occur over a
heterogeneous environment are subject to conditions of multiple stresses due to the
variety of weather conditions. In this context, water stress, flooding or deficit, has a
profound impact on ecological and agricultural systems. The kinetics of chlorophyll a
fluorescence is a quite sensitive to environmental stress, and small changes in
structure and operation, can be easily detected by their analysis. This work was
divided into three experiments, with the aim of evaluating the variation of the kinetics
of chlorophyll fluorescence in the plants of the genus Prunus. The first was
conducted in the field, the Centro Agropecuário da Palma, with six treatments
(rootstocks) associated with Maciel. They were accompanied by a period of
approximately 150 days the length of the leaf chlorophyll content and chlorophyll a
fluorescence kinetics. The second and third experiments were conducted in a
greenhouse to cultivate plum America (P. salicina) cultivar and hybrid-cup "GxN-9"
(P.dulcis Mill. X P.persica L. Batsch) respectively. In both experiments, plants were
kept for 11days under water restriction and 10 days of flooding, with three treatments
(control, drought and flooding). Analysis of gas exchange and chlorophyll a
fluorescence were monitored regularly every three days. During the experiment a
variation of fluorescence parameters are affected by ontogeny of the leaves and
especially the high rainfall recorded at 97 days of the beginning of the experiment. By analyzing of JIP-Test, damage to the photosynthetic system were checked, along
with the best association with Maciel x rootstock Rubirá. In experiment 2, plum plants
subjected to water stress, showed a reduction in photosynthesis due to reduced
stomatal conductance and the increase in the flow dissipation by reaction center
(DI/RC) most striking under conditions of water deficit. In the third experiment, the
lowest photosynthetic activity of the hybrid "GxN-9" is related to the decrease in
carboxylation efficiency, while the quantum yield of electron transport was more
affected by flooding. Thus, the results suggest that plants plum America is growing
more sensitive to water deficit conditions, and the rootstock hybrid "GxN-9", the
conditions of soil flooding. === O crescimento e o desenvolvimento de plantas da família das rosáceas apresentam
variações dos processos fisiológicos durante o ciclo anual. Espécies vegetais que
ocorrem ao longo de um ambiente heterogêneo estão sujeitas as condições de
múltiplos estresses devido à variedade das condições climáticas. Nesse contexto, o
estresse hídrico, por alagamento ou déficit, tem profundo impacto sobre sistemas
ecológicos e agrícolas. A cinética da fluorescência da clorofila a, apresenta-se
bastante sensível ao estresse ambiental e, pequenas alterações de estrutura e
funcionamento, podem ser facilmente detectadas por meio da sua análise. Este
trabalho foi dividido em três experimentos, com o objetivo de avaliar a variação da
cinética da fluorescência da clorofila a em plantas do gênero Prunus. O primeiro foi
conduzido a campo, no Centro Agropecuário da Palma, com seis tratamentos (portaenxertos)
associados a cultivar copa Maciel. Foram acompanhadas por um período
de aproximadamente 150 dias o comprimento da folha, o índice de clorofila e a
cinética da fluorescência da clorofila a. O segundo e terceiro experimento, foram
conduzidos em casa de vegetação com a cultivar de ameixeira América (P. salicina)
e a cultivar-copa do híbrido GxN-9 (P.dulcis Mill. X P.persica L. Batsch)
respectivamente. Em ambos os experimentos, as plantas foram mantidas durante 11
dias sob restrição hídrica e 10 dias de alagamento, totalizando três tratamentos
(controle, seca e alagamento do solo). Análise de trocas gasosas e fluorescência da
clorofila a, foram acompanhados regularmente a cada três dias. Durante o
experimento 1 a variação dos parâmetros de fluorescência sofreu interferência da
ontogenia das folhas e principalmente, da alta pluviosidade registrada aos 97 dias do
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