Call number: LD2668 .T4 1961 F45

The present investigation was undertaken as a preliminary study to learn the response of Escherichia coli cells grown under identical experimental conditions to various concentrations of indoleacetic acid, gibberellic acid, and kinetin alone, and in combination with one another.

The developmental programs of maturing seed and fruit in pea (Pisum sativum L.) are tightly controlled by the interactions of several phytohormones, including gibberellins (GAs), auxins, and abscisic acid (ABA). To more fully understand these hormone networks and their roles in controlling development, transcription profiles of GA metabolism genes and metabolite profiles of key GAs, auxins, and ABA were determined in developing seeds, and histological studies were employed to correlate physiology and hormone metabolism. Data suggest that bioactive GA stimulates several aspects of seed growth, and ABA appears to promote bioactive GA1 synthesis in rapidly growing seed coats, and inhibit GA biosynthesis in the embryo axes of maturing embryos. Two putative auxin receptor genes were cloned, and their transcription profiles examined in developing seed and pericarp tissues. Pericarp PsAFB6A transcription was responsive to auxin and seed signals, indicating a potential role for the modulation of auxin sensitivity in fruit development.

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Thesis (M. Ag. Sc.)--University of Adelaide, 1987. / Includes bibliographical references (leaves 213-223).

Made available in DSpace on 2014-08-13T14:50:53Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-04-04Bitstream added on 2014-08-13T18:01:23Z : No. of bitstreams: 1 000766009.pdf: 2133283 bytes, checksum: ba937fe476457437b0b6e44206820ee8 (MD5) / O presente trabalho objetivou avaliar o efeito da aplicação foliar da mistura de auxina (Ax), citocinina (CK) e giberelina (GA), isolada ou combinada com a mistura de nutrientes, cobalto (Co) e molibdênio (Mo), em videira ‘Crimson Seedless’, buscando analisar seus efeitos na duração da atividade fotossintética das folhas e no metabolismo e desenvolvimento da planta, bem como no aumento da produção e qualidade de frutos. Os experimentos foram desenvolvidos no município de Juazeiro – BA, Brasil, em blocos casualizados, com quatro tratamentos e seis blocos. Os tratamentos foram: T1 - Testemunha; T2 - CK+Ax+GA 1,8L ha-1; T3 - CK+Ax+GA 1,8L ha-1 + Co+Mo 1,0L ha-1; e T4 - CK+Ax+GA 1,8L ha-1 + Co+Mo 1,5L ha-1. As aplicações foram realizadas em três fases: primórdio de inflorescência, bagas chumbinho, e alongamento de bagas. No primeiro experimento, avaliou-se a duração da atividade fotossintética das folhas, através de avaliações nas trocas gasosas em folhas marcadas logo após a brotação, até o final do ciclo. No segundo experimento, foram avaliadas as trocas gasosas, atividades de enzimas antioxidantes, teores de carboidratos e clorofilas aos 3, 5, 7, 14 e 21 dias após a 1ª aplicação; aos 1, 3 e 5 dias após a 2ª aplicação e aos 1, 3, 5, 7, 14, 21 e 28 dias após a 3ª aplicação (DAA). Assim, as plantas mantiveram a atividade fotossintética durante todo o ciclo, até o final das avaliações, aos 133 dias após a brotação das folhas. Entretanto, observou-se que a aplicação de reguladores vegetais e nutrientes antecipou o momento em que as folhas atingiram a taxa de assimilação de CO2 máxima, indicando que esses tratamentos otimizaram o processo fotossintético. Ao mesmo tempo, as taxas de assimilação de CO2 e eficiência de carboxilação começaram a apresentar maior eficiência após 14 DAA, assim como maiores teores de clorofilas, carotenoides e ... / The present study aimed to evaluate the effect of foliar application of auxin (Ax), cytokinin (CK) and gibberellin (GA) mixture, isolated or combined with the cobalt (Co) and molybdenum (Mo) mixture, in 'Crimson Seedless' grapevine, analyzing their effects on photosynthetic activity duration, metabolism and development of the plant, as well as increase production and fruit quality. The experiments were conducted in Juazeiro - BA, Brazil, in a randomized block design with four treatments, six blocks, with four plants each. Treatments were: T1 - Control; T2 - CK+Ax+GA 1.8L ha-1, T3 - CK+Ax+GA 1.8L ha-1 + Co+Mo 1.0L ha-1, and T4 - CK+Ax+GA 1.8L h-1 + Co+Mo 1.5L h-1. The treatments applications were carried out in three phases: inflorescence primordial stage, when berries were with 6 to 8 mm in diameter and berries elongation. In the first experiment, the photosynthetic activity duration was assessed by evaluating gas exchanges in leaves that were marked soon after sprouting, until the end of the cycle. In the second experiment, were evaluated gas exchanges, antioxidant enzymes activities, levels of carbohydrates and chlorophyll at 3, 5, 7, 14 and 21 days after the 1st application, at 1, 3 and 5 days after 2nd application and at 1, 3 , 5, 7 , 14, 21 and 28 days after the 3rd application (DAA). Thus, plants maintained their photosynthetic activity during the whole cycle, until the end of evaluations, for 133 days after sprouting leaves. However, it was observed that the application of plant growth regulators and nutrients anticipating the moment when the leaves reached the maximum absorption rate of CO2, indicating that these treatments have optimized the photosynthetic process. At the same time, rates of CO2 assimilation and carboxylation efficiency began to show greater efficiency after 14 DAA, as well as higher levels of chlorophylls, carotenoids and sugar concentrations, as in the 1st far as ...

Orientador: João Domingos Rodrigues / Banca: Elizabeth Orika Ono / Banca: Gisela Ferreira / Banca: Osvaldo Ferrarese Filho / Banca: Stella Consorte Cato / Resumo: O presente trabalho objetivou avaliar o efeito da aplicação foliar da mistura de auxina (Ax), citocinina (CK) e giberelina (GA), isolada ou combinada com a mistura de nutrientes, cobalto (Co) e molibdênio (Mo), em videira 'Crimson Seedless', buscando analisar seus efeitos na duração da atividade fotossintética das folhas e no metabolismo e desenvolvimento da planta, bem como no aumento da produção e qualidade de frutos. Os experimentos foram desenvolvidos no município de Juazeiro - BA, Brasil, em blocos casualizados, com quatro tratamentos e seis blocos. Os tratamentos foram: T1 - Testemunha; T2 - CK+Ax+GA 1,8L ha-1; T3 - CK+Ax+GA 1,8L ha-1 + Co+Mo 1,0L ha-1; e T4 - CK+Ax+GA 1,8L ha-1 + Co+Mo 1,5L ha-1. As aplicações foram realizadas em três fases: primórdio de inflorescência, bagas chumbinho, e alongamento de bagas. No primeiro experimento, avaliou-se a duração da atividade fotossintética das folhas, através de avaliações nas trocas gasosas em folhas marcadas logo após a brotação, até o final do ciclo. No segundo experimento, foram avaliadas as trocas gasosas, atividades de enzimas antioxidantes, teores de carboidratos e clorofilas aos 3, 5, 7, 14 e 21 dias após a 1ª aplicação; aos 1, 3 e 5 dias após a 2ª aplicação e aos 1, 3, 5, 7, 14, 21 e 28 dias após a 3ª aplicação (DAA). Assim, as plantas mantiveram a atividade fotossintética durante todo o ciclo, até o final das avaliações, aos 133 dias após a brotação das folhas. Entretanto, observou-se que a aplicação de reguladores vegetais e nutrientes antecipou o momento em que as folhas atingiram a taxa de assimilação de CO2 máxima, indicando que esses tratamentos otimizaram o processo fotossintético. Ao mesmo tempo, as taxas de assimilação de CO2 e eficiência de carboxilação começaram a apresentar maior eficiência após 14 DAA, assim como maiores teores de clorofilas, carotenoides e ... / Abstract: The present study aimed to evaluate the effect of foliar application of auxin (Ax), cytokinin (CK) and gibberellin (GA) mixture, isolated or combined with the cobalt (Co) and molybdenum (Mo) mixture, in 'Crimson Seedless' grapevine, analyzing their effects on photosynthetic activity duration, metabolism and development of the plant, as well as increase production and fruit quality. The experiments were conducted in Juazeiro - BA, Brazil, in a randomized block design with four treatments, six blocks, with four plants each. Treatments were: T1 - Control; T2 - CK+Ax+GA 1.8L ha-1, T3 - CK+Ax+GA 1.8L ha-1 + Co+Mo 1.0L ha-1, and T4 - CK+Ax+GA 1.8L h-1 + Co+Mo 1.5L h-1. The treatments applications were carried out in three phases: inflorescence primordial stage, when berries were with 6 to 8 mm in diameter and berries elongation. In the first experiment, the photosynthetic activity duration was assessed by evaluating gas exchanges in leaves that were marked soon after sprouting, until the end of the cycle. In the second experiment, were evaluated gas exchanges, antioxidant enzymes activities, levels of carbohydrates and chlorophyll at 3, 5, 7, 14 and 21 days after the 1st application, at 1, 3 and 5 days after 2nd application and at 1, 3 , 5, 7 , 14, 21 and 28 days after the 3rd application (DAA). Thus, plants maintained their photosynthetic activity during the whole cycle, until the end of evaluations, for 133 days after sprouting leaves. However, it was observed that the application of plant growth regulators and nutrients anticipating the moment when the leaves reached the maximum absorption rate of CO2, indicating that these treatments have optimized the photosynthetic process. At the same time, rates of CO2 assimilation and carboxylation efficiency began to show greater efficiency after 14 DAA, as well as higher levels of chlorophylls, carotenoids and sugar concentrations, as in the 1st far as ... / Doutor

The plant hormones gibberellins (GAs) and auxin display overlapping activities in the regulation of multiple developmental processes, including the differential growth that mediates the response to tropic stimuli and the formation of the apical hook. Several mechanisms have been proposed that explain the interaction between these two hormones, such as the regulation of auxin transport by GAs, and the regulation of GA biosynthesis by auxin. GAs are known to exert their action at the transcriptional level by promoting the degradation of DELLA proteins, which in turn interact with numerous transcription factors and modulate their activity. We have identified INDOLE-3-ACETIC ACID METHYLTRANSFERASE 1 (IAMT1) as one of the earliest target genes upregulated after conditional expression of the DELLA protein GAI in Arabidopsis thaliana. In this Thesis, we have addressed two main issues: (1) the contribution of IAMT1 to auxin homeostasis and its biological relevance; and (2) the molecular mechanism by which DELLAs are able to induce the expression of IAMT1. Using combinations of iamt1 loss-of-function mutants and reporter lines for auxin accumulation and activity, we have found that IAMT1 activity is essential for proper generation and maintenance of the auxin gradients that underlie differential growth. According to our results, the role of IAMT1 would be to restrict polar auxin transport especially during the response to tropic stimuli, preventing excessive auxin accumulation in the responding tissues, and IAMT1 exerts this function, at least in part, by inhibiting the expression of the PIN genes, encoding auxin efflux carriers. Regarding the regulation of IAMT1 expression by DELLAs, dissection of the promoter, in silico analysis of putative DELLA partners, and molecular genetic analysis of reporter lines has allowed us to identify two mechanisms with different relevance depending on the environmental conditions, and through different cis elements. In etiolated seedlings, DELLA proteins are recruited by DORNRÖSCHEN (DRN) to the IAMT1 promoter to induce IAMT1 expression. In the light and in a temperature-dependent manner, DELLA proteins inhibit the DNA-binding activity of PHYTOCHROME-INTERACTING FACTOR4 (PIF4) and BRI1 EMS-SUPPRESSOR1(BES1), which act as repressors of IAMT1 expression. The work presented here highlights how GAs may affect local accumulation of auxin, being particularly relevant in processes that involve differential growth. / Abbas, M. (2014). The control of auxin homeostasis through the regulation of IAMT1 by DELLA proteins [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/39348 / TESIS

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