A greenhouse experiment was conducted over a ninety day period to test the effect of different nitrogen fertilizer regimes and several application rates of compounds with gibberellin and cytokinin activity (GA4/7 and BA, respectively) on the growth and development of Pinus brutia var. eldarica. Nitrogen produced no significant effects and this was attributed to its abundance in the potting medium, to begin with. All levels of growth regulators used showed a highly significant effect on vegetative development. A reduction in root collar diameter, shoot elongation, needle nitrogen content and oven-dry weight, was observed, especially when the medium and high hormonal rates were used. Phytotoxicity increased with the increase in concentration of both chemicals. Ba induced a proliferation of adventitious buds along the stem of saplings, but this was accompanied with rapid new top growth and branching at the top only when BA was applied in conjunction with GA4/7.

Les gibbérellines (GA) sont une classe de phytohormones modulant différents aspects du développement des plantes. La biosynthèse des GA est catalysée par l’activité de différentes classes d’enzymes permettant la formation des formes bioactives. Si les mutants de biosynthèse sont nains, un excès de l’hormone provoque croissance excessive et stérilité. Ainsi, les plantes ont développé des mécanismes efficaces leur permettant de maintenir une concentration optimale de GA bioactives. Un niveau supplémentaire de régulation peut être constitué par une séparation spatiale de la biosynthèse dans différents types cellulaires et organes. A l’aide d’approches variées, nous démontrons qu’une forme intermédiaire est mobile sur de longues distances. Ce transport s’effectue à travers les vaisseaux vasculaires de la plante, et pourrait impliquer des transporteurs. Ensembles, nos résultats révèlent la nature et les propriétés biologiques du transport de GA sur de longues distances chez Arabidopsis. / Gibberellins (GA) are a class of diterpenoid hormones regulating major aspects of plant growth. GA biosynthesis from GGDP is catalyzed by the activity of different classes of enzymes leading to the formation of the active forms of GA. Thus GA biosynthesis mutants are dwarfs and late flowering, while GA overdose causes excessive growth and sterility. Therefore plants have evolved efficient mechanisms to maintain optimal levels of bioactive GA. However, an additional level of regulation may reside in the separation of the GA biosynthetic pathway into distinct cell types and organs. Through micro-grafting, genetic and biochemical approaches, we demonstrate that a GA intermediate is mobile over long distances in Arabidopsis. Moreover, this transport occurs through vascular tissues of the plant, and may involve specific transporters. Altogether, our results reveal the nature and the biological properties of GA long distances transport in Arabidopsis.

Typecript Includes bibliographical references

Includes bibliographical refences

Tomato plants (Lycopersicon esculentum Mill.) were grown in the greenhouse and in the field during 1979 and 1980. The inflorescences were treated with gibberellin (GA4/7) and/or benzyladenine (BA). Root exudate was collected at various stages of growth and development for the estimation of the levels of cytokinins in the plant. Soluble sugars and starch were determined in inflorescences at different stages of development. Partitioning of dry matter between the different plant portions was studied to evaluate growth of tomato plants in two different conditions. The application of GA4/7 and BA to tomato inflorescences promoted the development and increased the number of flowers. These growth regulators substantially increased fruit set and yield of tomatoes in both greehouse and field experiments. Determinations of carbohydrates in inflorescences treated with growth regulators showed higher amounts of soluble sugars and starch over a considerable period of development. The level of cytokinins in root exudate was higher during early phase of vegetative growth. At the time of bud formation and anthesis, the level of cytokinins declined. The quantity of translocated cytokinins in the greenhouse was 4 to 5 times higher than under high temperatures in the field. The low levels of cytokinins were associated with poor flower development. Field grown tomato plants produced more vegetative growth and fewer inflorescences than plants in the greenhouse. Allocation of assimilates to newly developed leaves and low level of growth regulators in buds and inflorescences might contribute towards more vegetative growth but poor flowering under high temperatures.

Made available in DSpace on 2014-06-11T19:32:39Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-03-28Bitstream added on 2014-06-13T19:22:09Z : No. of bitstreams: 1 000757670.pdf: 1772920 bytes, checksum: ac3e161b26a22adc394755fc3cc1f63c (MD5) / Neste trabalho foram realizados três experimentos com o objetivo de estudar o efeito do regulador vegetal, etil-trinexapac, no crescimento e produção da planta de figueira (Ficus carica L.). O experimento 1 foi desenvolvido no período de 27 de agosto de 2011 a três de março de 2012 e o experimento 2, de 27 de agosto de 2012 a três de março de 2013. Os dois experimentos foram implantados em pomar comercial de cultivo de figueira cv. Roxo-de-Valinhos com quatro anos de idade, conduzidos em sequeiro (sem irrigação), sendo adicionados, regularmente, bagaço de cana nas linhas das plantas como cobertura morta (mulching) e destinando a produção de frutos verdes à indústria, no município de Caldas-MG. O experimento 3 (28 de março a 28 de julho de 2012) foi instalado em mudas de figueira cultivadas a pleno sol no Departamento de Horticultura, da Faculdade de Ciências Agronômicas do Campus de Botucatu da Universidade Estadual Paulista – UNESP, Botucatu-SP. Os três experimentos foram instalados em delineamento de blocos casualizados, considerando uma testemunha (sem aplicação) e, uma e duas aplicações de etil-trinexapac, em sete concentrações, na forma de solução: 0; 62,5; 62,5 + 62,5; 125; 125 + 125; 250; 250 + 250 e 500 mg L-1 de ingrediente ativo, distribuídos em quatro blocos. A parcela foi constituída por quatro plantas e uma planta de bordadura de cada lado da parcela. No experimento 1 e 2, a primeira pulverização foi realizada em ramos novos (brotações) padronizados com 50,0 cm de comprimento e contendo 12 entrenós (em torno de 12 gemas axilares). A segunda pulverização foi realizada nos mesmos ramos, 45 dias após a primeira aplicação. Já no experimento 3, a primeira pulverização foi realizada em ramos novos (brotações) padronizados com 26,0 cm de comprimento e contendo 16 entrenós (em torno de 16 gemas axilares). Já a segunda pulverização foi realizada nos mesmo... / In this work three experiments was to study the effect of the plant growth regulator, trinexapac-ethyl, on growth and yield of fig plant (Ficus carica L.). The experiment 1 was conducted during August 27th, 2011 to March 3th, 2012 and experiment 2, August 27th, 2012 to March 3th, 2013. The two experiments were carried out in a commercial orchard cultivation of fig cv. Roxo-de-Valinhos - four years old, conducted in rainfed (without irrigation), being added regularly, bagasse in the tree rows as mulch (mulching) and intended to produce green fruit industry in the municipality of Caldas - MG. The experiment 3 (March 28th to July 28th, 2012) was installed in fig seedlings grown in full sun in the Departmento de Horticultura, Faculdade de Ciências Agronômicas, Campus de Botucatu, Universidade Estadual Paulista - UNESP, Botucatu-SP. Three experiments were conducted in a randomized block design, considering one control (no application) and one or two applications of trinexapac-ethyl, in seven concentrations in solution form: 0; 62.5; 62.5 + 62.5; 125; 125 + 125; 250; 250 + 250 and 500 mg L-1 of active ingredient, distributed in four blocks. The plot consisted of four plants and one plant surround on each side of the plot. In experiment 1 and 2, the first spray was in new branches (shoots) standardized to 50.0 cm in length and containing 12 internodes (around 12 axillary buds). The second spraying was performed in the same lines, 45 days after the first application. Already in experiment 3, the first spray was in new branches (shoots) with standard 26.0 cm in length and containing 16 internodes (around 16 axillary buds). The second spraying was performed in the same lines, 45 days after the first application. The use of trinexapac-ethyl, both in one as in two applications of 250 mg L-1 did not affect a more pronounced effect on growth, increased plant height, number of internodes, length of the branch and ...

Orientador: Elizabeth Orika Ono / Banca: João Domingos Rodrigues / Banca: Giuseppina Pace Pereira Lima / Banca: Terezinha de Fatima Fumis / Banca: Aparecida Conceição Boliani / Resumo: Neste trabalho foram realizados três experimentos com o objetivo de estudar o efeito do regulador vegetal, etil-trinexapac, no crescimento e produção da planta de figueira (Ficus carica L.). O experimento 1 foi desenvolvido no período de 27 de agosto de 2011 a três de março de 2012 e o experimento 2, de 27 de agosto de 2012 a três de março de 2013. Os dois experimentos foram implantados em pomar comercial de cultivo de figueira cv. Roxo-de-Valinhos com quatro anos de idade, conduzidos em sequeiro (sem irrigação), sendo adicionados, regularmente, bagaço de cana nas linhas das plantas como cobertura morta (mulching) e destinando a produção de frutos verdes à indústria, no município de Caldas-MG. O experimento 3 (28 de março a 28 de julho de 2012) foi instalado em mudas de figueira cultivadas a pleno sol no Departamento de Horticultura, da Faculdade de Ciências Agronômicas do Campus de Botucatu da Universidade Estadual Paulista - UNESP, Botucatu-SP. Os três experimentos foram instalados em delineamento de blocos casualizados, considerando uma testemunha (sem aplicação) e, uma e duas aplicações de etil-trinexapac, em sete concentrações, na forma de solução: 0; 62,5; 62,5 + 62,5; 125; 125 + 125; 250; 250 + 250 e 500 mg L-1 de ingrediente ativo, distribuídos em quatro blocos. A parcela foi constituída por quatro plantas e uma planta de bordadura de cada lado da parcela. No experimento 1 e 2, a primeira pulverização foi realizada em ramos novos (brotações) padronizados com 50,0 cm de comprimento e contendo 12 entrenós (em torno de 12 gemas axilares). A segunda pulverização foi realizada nos mesmos ramos, 45 dias após a primeira aplicação. Já no experimento 3, a primeira pulverização foi realizada em ramos novos (brotações) padronizados com 26,0 cm de comprimento e contendo 16 entrenós (em torno de 16 gemas axilares). Já a segunda pulverização foi realizada nos mesmo ... / Abstract: In this work three experiments was to study the effect of the plant growth regulator, trinexapac-ethyl, on growth and yield of fig plant (Ficus carica L.). The experiment 1 was conducted during August 27th, 2011 to March 3th, 2012 and experiment 2, August 27th, 2012 to March 3th, 2013. The two experiments were carried out in a commercial orchard cultivation of fig cv. Roxo-de-Valinhos - four years old, conducted in rainfed (without irrigation), being added regularly, bagasse in the tree rows as mulch (mulching) and intended to produce green fruit industry in the municipality of Caldas - MG. The experiment 3 (March 28th to July 28th, 2012) was installed in fig seedlings grown in full sun in the Departmento de Horticultura, Faculdade de Ciências Agronômicas, Campus de Botucatu, Universidade Estadual Paulista - UNESP, Botucatu-SP. Three experiments were conducted in a randomized block design, considering one control (no application) and one or two applications of trinexapac-ethyl, in seven concentrations in solution form: 0; 62.5; 62.5 + 62.5; 125; 125 + 125; 250; 250 + 250 and 500 mg L-1 of active ingredient, distributed in four blocks. The plot consisted of four plants and one plant surround on each side of the plot. In experiment 1 and 2, the first spray was in new branches (shoots) standardized to 50.0 cm in length and containing 12 internodes (around 12 axillary buds). The second spraying was performed in the same lines, 45 days after the first application. Already in experiment 3, the first spray was in new branches (shoots) with standard 26.0 cm in length and containing 16 internodes (around 16 axillary buds). The second spraying was performed in the same lines, 45 days after the first application. The use of trinexapac-ethyl, both in one as in two applications of 250 mg L-1 did not affect a more pronounced effect on growth, increased plant height, number of internodes, length of the branch and ... / Doutor

Le fraisier diploïde (Fragaria vesca, 2x=14) comporte deux modes de reproduction : la reproduction sexuée via la floraison, et la multiplication végétative via la production de stolons. Cette espèce présente également deux types de floraison, non-remontants ou remontants, selon la période d’initiation florale du génotype. Chez le fraisier diploïde, le gène responsable de la remontée florale a été identifié comme étant l’homologue du répresseur floral TFL1 et celui du stolonnage reste inconnu. L’objectif de cette thèse est d’identifier le gène responsable du stolonnage et de mieux comprendre la balance entre les deux modes de reproduction, sexuée et asexuée, chez le fraisier diploïde. Une approche de cartographie fine associée à du NGS a permis d’identifier le gène responsable du stolonnage, FvGA20ox4. Ce gène intervient dans la voie de biosynthèse des gibbérellines. Les génotypes non-stolonnants présentent une délétion de neuf bases qui ne modifie pas le cadre de lecture du gène. L’observation cytologique des méristèmes axillaires montre que les génotypes mutés présentent un allongement des axillaires comme les génotypes sauvages mais que ces bourgeons nécrosent par la suite. Une étude de l’activité enzymatique de la protéine délétée de trois acides aminés a montré qu’elle était inactive et ne permettrait pas de transformer les précurseurs de GA (GA12) en GA intermédiaires, qui seront convertis en GA actives via d’autres enzymes. Chez les génotypes mutés, un apport de GA3 permet de restaurer l’émergence de stolons. L’étude de la balance entre les deux modes de reproduction a été étudiée au sein d’une population en ségrégation pour le stolonnage et la remontée florale. Une approche QTL a permis de confirmer le rôle des gènes TFL1 et GA20ox4 dans le devenir des méristèmes en floral ou stolon respectivement et d’identifier deux loci présents sur le LG3 et LG4 impliqués dans la variation quantitative de la floraison ou du stolonnage respectivement. Pour le stolonnage, une interaction forte entre TFL1 et GA20ox4 a été mise en évidence par ANOVA. De plus, le suivi hebdomadaire de cette population pendant deux ans a montré que le processus de remontée florale prédominait celui de stolonnage. En conclusion, les données obtenues permettent une meilleure compréhension du stolonnage et de la balance entre les deux modes de reproduction chez le fraisier diploïde. / The diploid woodland strawberry (2n=2x=14) is a good model for genetic and genomic studies since it presents a small genome completely sequenced and its generation period is short. This species displays two modes of reproduction, sexual with flowering and vegetative through runnering, which is the capacity to form stolon. In addition, this species displays contrasted genotypes for their variation of flowering length because of difference in the period of floral initiation. This trait is under the control of TFL1. However, the genetic and molecular control of vegetative reproduction is poorly understood as the one of the balance between the two modes of reproduction. The objective of this work was to characterize the gene responsible of runnering and to decipher genetically and physiologically the balance between the two modes of reproduction. By developing a strategy combining linkage map, bulks and NGS, we found that runnering is controlled by the gibberellin (GA) oxidase, FvGA20ox4. The loss of runnering function is caused by a deletion of nine nucleotides, which does not change the open reading frame of the RNA and leads to a protein shortened by three amino acids. The GA oxidase activity was confirmed in enzymatic activity assays with recombinant protein. In addition, the loss-of-function can be restored by exogenous GA3 application. The genetic architecture of the balance between two reproductive modes, sexual and vegetative, was deciphered based on QTL approach. Results showed that, beside the known roles of TFL1 and GA20ox4 genes in promoting perpetual flowering and runnering processes respectively, two loci localized on LG4 and LG3 were linked to the quantitative responses of these processes. In addition, TFL1 and GA20ox4 genes showed epistatic interaction, and the process of flowering was maintained as priority over runnering, which decreased. These results provided new insight in the genetic control of the relationship between sexual and vegetative reproduction.

L'étude de la ramification chez le pois, à partir des mutants hyper-ramifiés ramosus (rms) a permis de mettre en évidence l'existence d'une nouvelle famille d'hormones végétales : les strigolactones, inhibant la ramification des plantes à graines. La découverte de cette hormone végétale ouvre de nouvelles pistes de recherche sur la biosynthèse et la perception de cette nouvelle hormone. Nous avons montré le rôle du gène PsBRC1, codant un facteur de transcription de type TCP et homologue du gène TEOSINTE BRANCHED1 du maïs, dans la voie de signalisation des strigolactones. L’étude de ce gène nous a permis d'avoir une meilleure compréhension de l’interaction entre strigolactones et cytokinines dans le contrôle de la ramification, de la dynamique de la levée de dormance des bourgeons axillaires, et d'effectuer les premières études de relations structure-activité des strigolactones sur l’inhibition de la ramification chez le pois.Nous avons étudié et caractérisé d'autres éléments dans la voie de signalisation. Chez le pois, deux mutants, autres que Psbrc1, ne répondent pas à l’application de strigolactones, rms3 et rms4. Le gène RMS4 code pour une protéine à boîte F. Nous nous sommes focalisés ici sur le mutant hyper-ramifié rms3. Nous avons montré que RMS3 est l'homologue du gène D14 du riz, codant pour une protéine de la superfamille des α-β/hydrolases. Ces protéines peuvent avoir une activité enzymatique et ainsi pourraient modifier les strigolactones en un composé actif. Le récepteur des gibbérellines GID1 appartient aussi à cette famille, RMS3 est donc un bon candidat pour être le récepteur des strigolactones. Nous avons utilisé une strigolactone radiomarquée afin d’étudier le métabolisme de l'hormone. Nous avons découvert que la strigolactone synthétique, 3H-GR24 est clivée en un composé inconnu au contact des racines, indépendamment de l'activité de la protéine RMS3. Ce composé de structure inconnue se retrouve aussi dans la sève du xylème alors que 3H-GR24 y est absent.Outre un phénotype hyperbranché les mutants rms présentent une diminution de la taille de leurs entre-nœuds, qui n'est pas due à l’augmentation de la ramification. Nous avons étudié l'origine du nanisme des mutants déficients en strigolactones et affectés dans la réponse à l’hormone. Des approches génétiques et moléculaires ont été utilisées pour tester une interaction possible entre les strigolactones et les gibbérellines. Nous avons montré que les strigolactones régulaient l’élongation des entre-nœuds indépendamment des gibbérellines.Le pois est un excellent modèle en génétique et en physiologie. Avec le développement de nouvelles techniques à l'INRA (TILLING; UNIGENE : ensemble de plus de 40000 séquences exprimées de pois), nous avons pu identifier de nouveaux gènes de biosynthèse des strigolactones chez le pois et obtenir plusieurs nouveaux mutants de pois. Ces mutants seront essentiels pour les futures études du laboratoire et pourront permettre d'identifier de nouveaux intermédiaires dans la biosynthèse et le métabolisme des strigolactones. / The study of shoot branching in pea, using the high branching ramosus (rms) mutants has highlighted the existence of a new family of plant hormones: the strigolactones, inhibiting shoot branching in seed plants. The discovery of this novel plant hormone opens novel research areas in the deciphering of strigolactone biosynthesis and strigolactone perception. We have shown the role of the pea TCP transcription factor, PsBRC1, the homolog of the maize TEOSINTE BRANCHED (TB1) in strigolactone signaling. The PsBRC1 gene was shown to have a role in integrating strigolactone and cytokinin pathways, and allowed to have a better understanding of the dynamics of bud outgrowth, and to perform the first strigolactone Structure-Activity Relationship studies for branching inhibition in pea. We investigated and characterized other elements in the signaling pathway, including the strigolactone receptor. In pea, two mutants, other than Psbrc1, do not respond to the application of strigolactones, rms3 and rms4. The RMS4 gene encodes an F-BOX protein and here we focused on the high branching rms3 pea mutant. We have shown that RMS3 is the homolog of the rice D14 gene encoding a protein of the α-β/hydrolase superfamily. Consequently RMS3 may have an enzymatic activity to modify strigolactone into an active compound. The gibberellin receptor GID1 also belongs to this family, therefore RMS3 is also a good candidate for the strigolactone receptor. We used a radiolabeled synthetic strigolactone, 3H-GR24, to investigate the metabolism of the hormone. We discovered that the synthetic strigolactone, 3H-GR24 is cleaved in an unknown compound in the root media independently of RMS3 activity, compound which is also found in the xylem sap in contrast to 3H-GR24. The rms mutants exhibit not only a high branching phenotype but also a reduced height which is not due to this high branching. We investigated the origin of the dwarfism of strigolactone-deficient and response mutants in pea. Genetic and molecular approaches have been used to test a possible interaction between strigolactones and gibberellins. We have shown that strigolactones regulate stem elongation independently of gibberellin. Pea is a powerful model plant for genetics and physiology. With the development of new facilities at INRA (TILLING; UNIGENE set of more than 40000 expressed sequences), we were able to identify new biosynthesis genes in pea and to obtain several novel pea mutants. These mutants will be essential for future studies of the laboratory in particular to identify new intermediates in strigolactone biosynthesis and metabolism.

L’architecture du système racinaire des légumineuses est déterminée par la croissance des racines et leur capacité à former des racines latérales et des nodosités symbiotiques fixatrices d’azote en fonction des conditions environnementales. Chez la légumineuse modèle Medicago truncatula, nous avons mis en évidence que les phytohormones gibbérellines (GAs) et leur voie de signalisation – médiée par trois protéines MtDELLAs présentant des profils d’expression redondants – jouent un rôle clé dans la régulation du développement du système racinaire. En conditions non-symbiotiques, les GAs régulent négativement la croissance racinaire en réprimant l’activité méristématique et l’élongation cellulaire, et inhibent la formation des racines latérales. En conditions symbiotiques, le rôle des GAs et de leur voie de signalisation est double : au niveau de l’épiderme, les protéines MtDELLAs régulent positivement l’infection par les bactéries symbiotiques Rhizobia en interagissant de façon directe avec la voie de signalisation des facteurs Nod bactériens. Au niveau du cortex, les GAs régulent négativement l’organogénèse des nodosités. Les phytohormones cytokinines (CKs) et leur récepteur MtCRE1 étant essentiels pour initier la nodulation, l’interaction entre les voies de signalisation GA et CK a été analysée en parallèle. Les CKs régulent le niveau de GAs bioactives en modulant l’expression des gènes de leur métabolisme de manière dépendante du récepteur aux CKs MtCRE1. Réciproquement, les GAs régulent les gènes du métabolisme CK et le niveau de CKs bioactives de manière dépendante des MtDELLAs. Par ailleurs, une forme activée de MtDELLA complémente partiellement le phénotype de nodulation du mutant cre1 et lie le promoteur de MtCRE1, indiquant que les voies de signalisation GA et CK régulent la nodulation en étroite association. / Legume root system architecture is determined by both root growth and their ability to form lateral roots and nitrogen-fixing symbiotic nodules, depending on environmental soil conditions. In the model legume Medicago truncatula, we have shown that the phytohormones gibberellins (GAs) and their signaling – involving three MtDELLA proteins with redundant expression patterns – play a crucial role in the regulation of the root system development. In non-symbiotic conditions, GAs negatively regulate root growth through the repression of meristematic activity and cell elongation, and inhibit lateral root formation. In symbiotic conditions, GA and their signaling pathway play a dual role: in the root epidermis, MtDELLA proteins positively regulate infection by symbiotic bacteria Rhizobia, by directly interacting with the bacterial Nod factor signaling pathway. In the root cortex, GAs negatively regulate nodule organogenesis. The phytohormones cytokinins (CKs) and their receptor MtCRE1 being essential for the initiation of nodulation, we additionally analyzed the crosstalk between GA and CK signaling. CKs regulate the bioactive GA pool, controlling the expression of GA-metabolic genes, depending on the MtCRE1 receptor. In turn, GAs regulate CK-metabolic genes and the bioactive CK pool, depending on MtDELLAs. In addition, a dominant version of a MtDELLA partially complements the nodulation phenotype of the cre1 mutant and binds to the MtCRE1 promoter. These results indicate that GA and CK signaling pathways closely interact to regulate nodulation.