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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Fitotoxidez do óleo essencial de Heterothalamus psiadioides LESS sobre Arabidopsis thaliana (L.) HEYNH

Lazarotto, Diana Carla January 2014 (has links)
O arbusto Heterothalamus psiadioides Less. (Asteraceae) ocorre no sul do Brasil e no Uruguai, se estabelecendo frequentemente em formações densas. Esse padrão de estabelecimento pode estar relacionado a efeitos alelopáticos dos voláteis liberados por essa planta. Portanto, este trabalho objetivou investigar os efeitos do óleo essencial de H. psiadioides sobre a germinação, crescimento inicial, enraizamento adventício e desenvolvimento vegetativo e reprodutivo de Arabidopsis thaliana (L.) Heynh., planta-alvo desse estudo. Além disso, a caracterização química do óleo essencial foi realizada. Para avaliar efeitos sobre a germinação e o crescimento inicial, sementes e plântulas de A. thaliana foram expostas aos voláteis de H. psiadioides, cuja composição química foi analisada através de cromatografia em fase gasosa associada à espectrometria de massas. Para avaliar efeitos sobre o enraizamento adventício, plântulas de A. thaliana tiveram suas raízes primárias cortadas, gerando microestacas que foram expostas aos voláteis. Além disso, tratamentos para recuperação dos efeitos causados pelos voláteis foram utilizados – com adição de auxina, citocinina e antioxidante ao meio de cultura. No experimento que testou os efeitos dos voláteis sobre o desenvolvimento reprodutivo e vegetativo da planta-alvo, as plantas foram expostas aos voláteis dentro de câmaras de vidro. Após a exposição e quando as plantas senesceram, parâmetros vegetativos e reprodutivos foram avaliados. A germinação e o crescimento inicial da planta-alvo foram afetados negativamente pelos voláteis de H. psiadioides. Da mesma forma, o enraizamento adventício das plantas foi afetado. Microestacas da planta-alvo expostas aos voláteis demoraram mais tempo para enraizar, desenvolveram menos raízes e essas eram mais curtas do que as microestacas controle. Estresse oxidativo foi detectado nas microestacas expostas aos voláteis; além disso, hormônios e antioxidante não reverteram os efeitos fisiológicos negativos causados pelos mesmos. A avaliação do desenvolvimento vegetativo e reprodutivo das plantas expostas aos voláteis nas câmaras de vidro permitiu detectar efeitos negativos dos voláteis apenas em um parâmetro relacionado ao crescimento, que foi mensurado logo após o período de exposição. Nenhum outro parâmetro diferiu significativamente entre plantas expostas aos voláteis e não expostas. Esses resultados indicam que apesar dos drásticos efeitos demonstrados pelos voláteis sobre sementes e plântulas, efeitos pouco relevantes foram encontrados para o desenvolvimento vegetativo e reprodutivo. Portanto, possivelmente o potencial alelopático de H. psiadioides pode ser menor do que o esperado, já que plantas juvenis a adultas são capazes de recuperar-se dos efeitos dos voláteis dessa planta. / The shrub Heterothalamus psiadioides Less. (Asteraceae) occurs in Southern Brazil and Uruguay, where it often establishes in dense populations. This pattern of establishment may be related to allelopathic effects of the volatiles released by this plant. Therefore, this study aims to investigate the effects of the volatile essential oil of H. psiadioides on germination, early growth, adventitious rooting and vegetative and reproductive development of Arabidopsis thaliana (L.) Heynh., the target plant of this study. Furthermore, the chemical characterization of the essential oil was performed. To assess effects on germination and early growth, seeds and seedlings of A. thaliana were exposed to H. psiadioides volatiles, which had the chemical composition analyzed by gas chromatography coupled to mass spectrometry. To evaluate effects on adventitious rooting, seedlings of A. thaliana had the primary roots excised, generating microcuttings that were exposed to the volatiles. Moreover, treatments to recovery the effects caused by the volatiles were used – with addition of auxin, cytokinin and antioxidant in the culture medium. In the experiment that tested the effects of the volatiles on the vegetative and reproductive development of the target plant, plants were exposed to the volatiles inside of glass chambers. After the exposition and at senescence, vegetative and reproductive parameters were evaluated. The germination and early growth were negatively affected by the volatiles. Adventitious rooting was similarly affected. Microcuttings of the target plant exposed to the volatiles were slower to root, less developed and had shorter roots in relation to control microcuttings. Oxidative damage was detected in the microcuttings exposed to the volatiles; furthermore hormones and antioxidant did not revert negative physiological effects caused by the oil. The evaluation of vegetative and reproductive development of plants exposed to the volatiles inside of glass chambers allowed to detect negative effects just in a parameter measured immediately after removal plants from the chambers. Other parameters did not differ between plants exposed to the volatiles and plants not exposed. These results indicate that despite of drastic effects showed by the volatiles on seeds and seedlings, effects of little relevance were found in vegetative and reproductive development. Therefore, it is possible that allelopathic potential of H. psiadioides may be lower than expected, since juvenile and adult plants are able to recover from the effects of the plant volatiles.
2

Fitotoxidez do óleo essencial de Heterothalamus psiadioides LESS sobre Arabidopsis thaliana (L.) HEYNH

Lazarotto, Diana Carla January 2014 (has links)
O arbusto Heterothalamus psiadioides Less. (Asteraceae) ocorre no sul do Brasil e no Uruguai, se estabelecendo frequentemente em formações densas. Esse padrão de estabelecimento pode estar relacionado a efeitos alelopáticos dos voláteis liberados por essa planta. Portanto, este trabalho objetivou investigar os efeitos do óleo essencial de H. psiadioides sobre a germinação, crescimento inicial, enraizamento adventício e desenvolvimento vegetativo e reprodutivo de Arabidopsis thaliana (L.) Heynh., planta-alvo desse estudo. Além disso, a caracterização química do óleo essencial foi realizada. Para avaliar efeitos sobre a germinação e o crescimento inicial, sementes e plântulas de A. thaliana foram expostas aos voláteis de H. psiadioides, cuja composição química foi analisada através de cromatografia em fase gasosa associada à espectrometria de massas. Para avaliar efeitos sobre o enraizamento adventício, plântulas de A. thaliana tiveram suas raízes primárias cortadas, gerando microestacas que foram expostas aos voláteis. Além disso, tratamentos para recuperação dos efeitos causados pelos voláteis foram utilizados – com adição de auxina, citocinina e antioxidante ao meio de cultura. No experimento que testou os efeitos dos voláteis sobre o desenvolvimento reprodutivo e vegetativo da planta-alvo, as plantas foram expostas aos voláteis dentro de câmaras de vidro. Após a exposição e quando as plantas senesceram, parâmetros vegetativos e reprodutivos foram avaliados. A germinação e o crescimento inicial da planta-alvo foram afetados negativamente pelos voláteis de H. psiadioides. Da mesma forma, o enraizamento adventício das plantas foi afetado. Microestacas da planta-alvo expostas aos voláteis demoraram mais tempo para enraizar, desenvolveram menos raízes e essas eram mais curtas do que as microestacas controle. Estresse oxidativo foi detectado nas microestacas expostas aos voláteis; além disso, hormônios e antioxidante não reverteram os efeitos fisiológicos negativos causados pelos mesmos. A avaliação do desenvolvimento vegetativo e reprodutivo das plantas expostas aos voláteis nas câmaras de vidro permitiu detectar efeitos negativos dos voláteis apenas em um parâmetro relacionado ao crescimento, que foi mensurado logo após o período de exposição. Nenhum outro parâmetro diferiu significativamente entre plantas expostas aos voláteis e não expostas. Esses resultados indicam que apesar dos drásticos efeitos demonstrados pelos voláteis sobre sementes e plântulas, efeitos pouco relevantes foram encontrados para o desenvolvimento vegetativo e reprodutivo. Portanto, possivelmente o potencial alelopático de H. psiadioides pode ser menor do que o esperado, já que plantas juvenis a adultas são capazes de recuperar-se dos efeitos dos voláteis dessa planta. / The shrub Heterothalamus psiadioides Less. (Asteraceae) occurs in Southern Brazil and Uruguay, where it often establishes in dense populations. This pattern of establishment may be related to allelopathic effects of the volatiles released by this plant. Therefore, this study aims to investigate the effects of the volatile essential oil of H. psiadioides on germination, early growth, adventitious rooting and vegetative and reproductive development of Arabidopsis thaliana (L.) Heynh., the target plant of this study. Furthermore, the chemical characterization of the essential oil was performed. To assess effects on germination and early growth, seeds and seedlings of A. thaliana were exposed to H. psiadioides volatiles, which had the chemical composition analyzed by gas chromatography coupled to mass spectrometry. To evaluate effects on adventitious rooting, seedlings of A. thaliana had the primary roots excised, generating microcuttings that were exposed to the volatiles. Moreover, treatments to recovery the effects caused by the volatiles were used – with addition of auxin, cytokinin and antioxidant in the culture medium. In the experiment that tested the effects of the volatiles on the vegetative and reproductive development of the target plant, plants were exposed to the volatiles inside of glass chambers. After the exposition and at senescence, vegetative and reproductive parameters were evaluated. The germination and early growth were negatively affected by the volatiles. Adventitious rooting was similarly affected. Microcuttings of the target plant exposed to the volatiles were slower to root, less developed and had shorter roots in relation to control microcuttings. Oxidative damage was detected in the microcuttings exposed to the volatiles; furthermore hormones and antioxidant did not revert negative physiological effects caused by the oil. The evaluation of vegetative and reproductive development of plants exposed to the volatiles inside of glass chambers allowed to detect negative effects just in a parameter measured immediately after removal plants from the chambers. Other parameters did not differ between plants exposed to the volatiles and plants not exposed. These results indicate that despite of drastic effects showed by the volatiles on seeds and seedlings, effects of little relevance were found in vegetative and reproductive development. Therefore, it is possible that allelopathic potential of H. psiadioides may be lower than expected, since juvenile and adult plants are able to recover from the effects of the plant volatiles.
3

Fitotoxidez do óleo essencial de Heterothalamus psiadioides LESS sobre Arabidopsis thaliana (L.) HEYNH

Lazarotto, Diana Carla January 2014 (has links)
O arbusto Heterothalamus psiadioides Less. (Asteraceae) ocorre no sul do Brasil e no Uruguai, se estabelecendo frequentemente em formações densas. Esse padrão de estabelecimento pode estar relacionado a efeitos alelopáticos dos voláteis liberados por essa planta. Portanto, este trabalho objetivou investigar os efeitos do óleo essencial de H. psiadioides sobre a germinação, crescimento inicial, enraizamento adventício e desenvolvimento vegetativo e reprodutivo de Arabidopsis thaliana (L.) Heynh., planta-alvo desse estudo. Além disso, a caracterização química do óleo essencial foi realizada. Para avaliar efeitos sobre a germinação e o crescimento inicial, sementes e plântulas de A. thaliana foram expostas aos voláteis de H. psiadioides, cuja composição química foi analisada através de cromatografia em fase gasosa associada à espectrometria de massas. Para avaliar efeitos sobre o enraizamento adventício, plântulas de A. thaliana tiveram suas raízes primárias cortadas, gerando microestacas que foram expostas aos voláteis. Além disso, tratamentos para recuperação dos efeitos causados pelos voláteis foram utilizados – com adição de auxina, citocinina e antioxidante ao meio de cultura. No experimento que testou os efeitos dos voláteis sobre o desenvolvimento reprodutivo e vegetativo da planta-alvo, as plantas foram expostas aos voláteis dentro de câmaras de vidro. Após a exposição e quando as plantas senesceram, parâmetros vegetativos e reprodutivos foram avaliados. A germinação e o crescimento inicial da planta-alvo foram afetados negativamente pelos voláteis de H. psiadioides. Da mesma forma, o enraizamento adventício das plantas foi afetado. Microestacas da planta-alvo expostas aos voláteis demoraram mais tempo para enraizar, desenvolveram menos raízes e essas eram mais curtas do que as microestacas controle. Estresse oxidativo foi detectado nas microestacas expostas aos voláteis; além disso, hormônios e antioxidante não reverteram os efeitos fisiológicos negativos causados pelos mesmos. A avaliação do desenvolvimento vegetativo e reprodutivo das plantas expostas aos voláteis nas câmaras de vidro permitiu detectar efeitos negativos dos voláteis apenas em um parâmetro relacionado ao crescimento, que foi mensurado logo após o período de exposição. Nenhum outro parâmetro diferiu significativamente entre plantas expostas aos voláteis e não expostas. Esses resultados indicam que apesar dos drásticos efeitos demonstrados pelos voláteis sobre sementes e plântulas, efeitos pouco relevantes foram encontrados para o desenvolvimento vegetativo e reprodutivo. Portanto, possivelmente o potencial alelopático de H. psiadioides pode ser menor do que o esperado, já que plantas juvenis a adultas são capazes de recuperar-se dos efeitos dos voláteis dessa planta. / The shrub Heterothalamus psiadioides Less. (Asteraceae) occurs in Southern Brazil and Uruguay, where it often establishes in dense populations. This pattern of establishment may be related to allelopathic effects of the volatiles released by this plant. Therefore, this study aims to investigate the effects of the volatile essential oil of H. psiadioides on germination, early growth, adventitious rooting and vegetative and reproductive development of Arabidopsis thaliana (L.) Heynh., the target plant of this study. Furthermore, the chemical characterization of the essential oil was performed. To assess effects on germination and early growth, seeds and seedlings of A. thaliana were exposed to H. psiadioides volatiles, which had the chemical composition analyzed by gas chromatography coupled to mass spectrometry. To evaluate effects on adventitious rooting, seedlings of A. thaliana had the primary roots excised, generating microcuttings that were exposed to the volatiles. Moreover, treatments to recovery the effects caused by the volatiles were used – with addition of auxin, cytokinin and antioxidant in the culture medium. In the experiment that tested the effects of the volatiles on the vegetative and reproductive development of the target plant, plants were exposed to the volatiles inside of glass chambers. After the exposition and at senescence, vegetative and reproductive parameters were evaluated. The germination and early growth were negatively affected by the volatiles. Adventitious rooting was similarly affected. Microcuttings of the target plant exposed to the volatiles were slower to root, less developed and had shorter roots in relation to control microcuttings. Oxidative damage was detected in the microcuttings exposed to the volatiles; furthermore hormones and antioxidant did not revert negative physiological effects caused by the oil. The evaluation of vegetative and reproductive development of plants exposed to the volatiles inside of glass chambers allowed to detect negative effects just in a parameter measured immediately after removal plants from the chambers. Other parameters did not differ between plants exposed to the volatiles and plants not exposed. These results indicate that despite of drastic effects showed by the volatiles on seeds and seedlings, effects of little relevance were found in vegetative and reproductive development. Therefore, it is possible that allelopathic potential of H. psiadioides may be lower than expected, since juvenile and adult plants are able to recover from the effects of the plant volatiles.
4

Réponses développementales et physiologiques de la Microvigne aux températures élevées : caractérisation de l’effet sur le bilan carboné et son implication dans l’avortement précoce des organes reproducteurs. / Exploring the Microvine developmental and physiological adaptation mechanisms to elevated temperature : characterization of the impact on carbon balance and its involvement in early reproductive development failure

Luchaire, Nathalie 28 July 2015 (has links)
Dans le contexte de réchauffement climatique, le maintien des rendements est un enjeu majeur pour la filière viticole. L'augmentation des températures impacte négativement certaines phases clés du développement reproducteur en induisant notamment des phénomènes de coulure ou de pertes précoces d'inflorescence. L'altération du bilan carboné pourrait être un facteur majeur des diminutions de rendements en réponse aux températures élevées et l'évaluation de cette hypothèse permettrait d'ajuster les pratiques pour limiter les effets du réchauffement climatique. Si l'implication du bilan de carbone chez les plantes annuelles semble être à la base des baisses de rendement observées ces dernières années, les choses sont beaucoup moins claires chez des pérennes comme la vigne du fait des très nombreux co-facteurs possible ainsi que de la difficulté à expérimenter dans des conditions totalement contrôlées. Afin de s'affranchir de ces contraintes, notre étude a été réalisée en conditions contrôlées sur la Microvigne, un mutant naturel insensible à l'acide gibberelique et un nouveau modèle d'étude pour la génétique et la physiologie de la vigne. Ce mutant présente un phénotype nain et une floraison et fructification continues le long de l'axe proleptique. L'approche utilisée dans cette étude a consisté à (i) développer un cadre d'analyse adapté à la Microvigne; (ii) décrire l'impact de l'élévation de la température, sur les développements végétatif et reproducteur de la vigne, et plus particulièrement l'avortement des stades précoces du développement reproducteur; (iii) caractériser les changements du bilan de carbone de la Microvigne induits par la contrainte thermique, et enfin (iv) évaluer l'implication potentielle du bilan de carbone dans les phénomènes d'avortement précoces en réponse au stress thermique. Ce travail a permis de mettre en évidence des phénomènes d'avortement complet d'inflorescences en réponse à l'élévation des températures. Par ailleurs, nous avons pu montrer un rôle du statut carboné dans ce phénomène, soit via les teneurs totales en carbohydrates, soit via l'état global des réserves à l'échelle de la plante. Ce travail montre les potentialités su modèle Microvigne et ouvre de nouvelles perspectives pour l'analyse des effets des contraintes abiotiques sur le développement végétatif et reproducteur de la vigne. / Global warming is likely to be a major issue for grapevine yield sustainability in the next years. A common hypothesis is that long-term elevated temperatures may cause the failure of key phases of reproductive development, through their negative impact on carbon balance. However, testing the specific role of plant carbon status on yield elaboration under elevated temperatures is difficult on perennial crops, such as grapevine, and when environment fluctuates. To overcome these difficulties, the present work was conducted under fully controlled environment using a natural, giberrelic acid insensitive mutant of grapevine called Microvine, as a new model for grapevine genetics and physiological studies. This mutant present a dwarf stature and lack of juvenile characteristics leading to the continuous flowering and fruiting even during the first year after sowing. The present study was aimed at (i) developing a framework of analysis for Microvine; (ii) describing vegetative and reproductive developments responses to temperature elevation at whole plant level, and more precisely on early reproductive development abortions; (iii) characterizing grapevine carbon balance responses to temperature; and finally (iv) evaluating carbon balance implication in temperature-dependent early reproductive development abortions. This work shows that complete inflorescence abortions observed in response to temperature were related to carbon status, either expressed though total carbohydrate, or through the level of reserves at the whole plant level. This study opens the way to use Microvine as model to address the impact of climate warming on grapevine vegetative and reproductive developments.

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