A família Meliaceae compreende cerca de 51 gêneros e 550 espécies distribuídas principalmente na região Neotropical. Incluídas nesta família, estão espécies de elevado interesse comercial para a produção de madeiras nobres. Há carência de informações quanto à biologia floral dessas espécies, que aliada a problemas silviculturas dificulta a elaboração de programas efetivos de melhoramento genético das espécies de interesse econômico da família. O presente trabalho visa contribuir para o entendimento do desenvolvimento floral na família Meliaceae, com destaque para sete espécies de interesse econômico e/ou ecológico: Cedrela fissilis L., Cedrela odorata L., Swietenia macrophylla R. A. King, Trichilia claussenii C. DC., Guarea guidonea (L.) Sleumer, Toona ciliata M. J. Roem e Melia azedarach L. Para os estudos morfo-anatômicos utilizaram-se técnicas de microscopia óptica e microscopia eletrônica de varredura. Analisou-se igualmente o padrão de expressão de genes do modelo ABC, relacionados ao desenvolvimento floral, via hibridização in situ. Os estudos morfo-anatômicos permitiram caracterizar o desenvolvimento dos primórdios dos órgãos florais e o estabelecimento de estágios arbitrários de desenvolvimento, auxiliando na caracterização da expressão gênica. Estes resultados permitiram ainda a identificação de flores funcionalmente femininas ou masculinas em S. macrophylla C. fissilis, C. odorata e T. ciliata, as quais apresentam dimorfismo sexual. O padrão de expressão dos homólogos dos genes: APETALA1 (AP1), APETALA3 (AP3) e AGAMOUS (AG) foram diferentes daqueles previstos pelo modelo ABC. A expressão dos homólogos de AP1 foi verificada em todo o meristema floral nos estágios iniciais de desenvolvimento, em todas as espécies estudadas. O sinal de expressão concentrou-se nos primórdios das sépalas e pétalas em estágios mais avançados do desenvolvimento, porém um fraco sinal de hibridização de AP1 foi verificado em todos os verticilos. A expressão dos homólogos de AP3 foi verificada nas regiões previstas pelo modelo ABC, correspondentes ao segundo e terceiro verticilos. Porém um fraco sinal de AP3 foi também observado no quarto verticilo, o que não é previsto pelo modelo teórico. A expressão dos homólogos de AG foi restrita à região central do meristema floral, correspondente ao terceiro e quarto verticilos, em todos os estágios do desenvolvimento floral de todas as espécies estudadas. Entretanto, sinais adicionais de hibridização dos homólogos de AG foram visualizados na região abaxial dos primórdios de sépalas e pétalas em C. fissilis, C. odorata e T. ciliata. Os estudos da expressão dos genes do modelo ABC em Meliaceae revelaram padrões de expressão que não concordam com o modelo teórico vigente do controle molecular da determinação da identidade dos órgãos florais._________________________________________________________________________________________ ABSTRACT: The Meliaceae family comprises approximately 51 genus and 550 species mainly distributed in the Neotropical region. In this family there are many species of commercial interest for the production of noble wood. The lack of information on the floral biology associated with silvicultural problems limits the elaboration of effective breeding programs with species of economic interest. The present work aims to contribute with the understanding of floral development in Meliaceae, focusing in seven species of economical or ecological interest: Cedrela fissilis L., Cedrela odorata L., Swietenia macrophylla R. A. King, Trichilia claussenii C. DC., Guarea guidonea (L.) Sleumer, Toona ciliata M. J. Roem e Melia azedarach L. Morpho-anatomical analyses were done by light and scannning electron microscopy. The expression pattern of the ABC model genes, which are related to floral development, was analyzed by in situ hybridization. The characterization of the development of floral organ primordia and the establishment of arbitrary stages of floral development was done and was important for the characterization of gene expression. These results allowed for the identification of functionally female and male flowers in Swietenia macrophylla, Cedrela fissilis, Cedrela odorata and Toona ciliata, characterizing sexual dimorphism. The patterns of gene expression of the homologous of APETALA 1, APETALA 3 and AGAMOUS were different from those predicted by the ABC model. AP1 expression was observed in the entire floral meristem in the initial stages of development, in all seven species. The expression signal was more concentrated in sepal and petal primordia in further stages of development, although a weak hybridization signal of AP1 was verified in all four whorls. The expression of AP3 homologs was observed in the second and third whorls, as predicted by the ABC model. However, a weak signal of AP3 was also observed in the forth whorl, which was not predicted by the ABC model. AG homolog expression was restricted to the central region of the floral meristem, corresponding to the third and forth whorls, in all stages of development of all seven species. However, additional hybridization signal of AG homologs were seen in the abaxial region of sepal and petal primordia in Cedrela fissilis, Cedrela odorata and Toona ciliata. The analyses of the ABC model genes in Meliaceae revealed that the expression patterns do not agree with the theoretical currently accepted model that determines the molecular control of the identity of the floral organs.

A família Meliaceae compreende cerca de 51 gêneros e 550 espécies distribuídas principalmente na região Neotropical. Incluídas nesta família, estão espécies de elevado interesse comercial para a produção de madeiras nobres. Há carência de informações quanto à biologia floral dessas espécies, que aliada a problemas silviculturas dificulta a elaboração de programas efetivos de melhoramento genético das espécies de interesse econômico da família. O presente trabalho visa contribuir para o entendimento do desenvolvimento floral na família Meliaceae, com destaque para sete espécies de interesse econômico e/ou ecológico: Cedrela fissilis L., Cedrela odorata L., Swietenia macrophylla R. A. King, Trichilia claussenii C. DC., Guarea guidonea (L.) Sleumer, Toona ciliata M. J. Roem e Melia azedarach L. Para os estudos morfo-anatômicos utilizaram-se técnicas de microscopia óptica e microscopia eletrônica de varredura. Analisou-se igualmente o padrão de expressão de genes do modelo ABC, relacionados ao desenvolvimento floral, via hibridização in situ. Os estudos morfo-anatômicos permitiram caracterizar o desenvolvimento dos primórdios dos órgãos florais e o estabelecimento de estágios arbitrários de desenvolvimento, auxiliando na caracterização da expressão gênica. Estes resultados permitiram ainda a identificação de flores funcionalmente femininas ou masculinas em S. macrophylla C. fissilis, C. odorata e T. ciliata, as quais apresentam dimorfismo sexual. O padrão de expressão dos homólogos dos genes: APETALA1 (AP1), APETALA3 (AP3) e AGAMOUS (AG) foram diferentes daqueles previstos pelo modelo ABC. A expressão dos homólogos de AP1 foi verificada em todo o meristema floral nos estágios iniciais de desenvolvimento, em todas as espécies estudadas. O sinal de expressão concentrou-se nos primórdios das sépalas e pétalas em estágios mais avançados do desenvolvimento, porém um fraco sinal de hibridização de AP1 foi verificado em todos os verticilos. A expressão dos homólogos de AP3 foi verificada nas regiões previstas pelo modelo ABC, correspondentes ao segundo e terceiro verticilos. Porém um fraco sinal de AP3 foi também observado no quarto verticilo, o que não é previsto pelo modelo teórico. A expressão dos homólogos de AG foi restrita à região central do meristema floral, correspondente ao terceiro e quarto verticilos, em todos os estágios do desenvolvimento floral de todas as espécies estudadas. Entretanto, sinais adicionais de hibridização dos homólogos de AG foram visualizados na região abaxial dos primórdios de sépalas e pétalas em C. fissilis, C. odorata e T. ciliata. Os estudos da expressão dos genes do modelo ABC em Meliaceae revelaram padrões de expressão que não concordam com o modelo teórico vigente do controle molecular da determinação da identidade dos órgãos florais. / The Meliaceae family comprises approximately 51 genus and 550 species mainly distributed in the Neotropical region. In this family there are many species of commercial interest for the production of noble wood. The lack of information on the floral biology associated with silvicultural problems limits the elaboration of effective breeding programs with species of economic interest. The present work aims to contribute with the understanding of floral development in Meliaceae, focusing in seven species of economical or ecological interest: Cedrela fissilis L., Cedrela odorata L., Swietenia macrophylla R. A. King, Trichilia claussenii C. DC., Guarea guidonea (L.) Sleumer, Toona ciliata M. J. Roem e Melia azedarach L. Morpho-anatomical analyses were done by light and scannning electron microscopy. The expression pattern of the ABC model genes, which are related to floral development, was analyzed by in situ hybridization. The characterization of the development of floral organ primordia and the establishment of arbitrary stages of floral development was done and was important for the characterization of gene expression. These results allowed for the identification of functionally female and male flowers in Swietenia macrophylla, Cedrela fissilis, Cedrela odorata and Toona ciliata, characterizing sexual dimorphism. The patterns of gene expression of the homologous of APETALA 1, APETALA 3 and AGAMOUS were different from those predicted by the ABC model. AP1 expression was observed in the entire floral meristem in the initial stages of development, in all seven species. The expression signal was more concentrated in sepal and petal primordia in further stages of development, although a weak hybridization signal of AP1 was verified in all four whorls. The expression of AP3 homologs was observed in the second and third whorls, as predicted by the ABC model. However, a weak signal of AP3 was also observed in the forth whorl, which was not predicted by the ABC model. AG homolog expression was restricted to the central region of the floral meristem, corresponding to the third and forth whorls, in all stages of development of all seven species. However, additional hybridization signal of AG homologs were seen in the abaxial region of sepal and petal primordia in Cedrela fissilis, Cedrela odorata and Toona ciliata. The analyses of the ABC model genes in Meliaceae revealed that the expression patterns do not agree with the theoretical currently accepted model that determines the molecular control of the identity of the floral organs.

Cette thèse aborde l’écologie et l’évolution des relations qu’entretiennent les orchidées du genre Ophrys avec leurs pollinisateurs. L’approche comparative et la combinaison (i)<p>d’analyses chimiques de phéromones sexuelles et de parfums floraux, (ii) d’analyses génétiques avec des outils moléculaires, et (ii) de tests de comportement réalisés sur les insectes in situ nous ont permis d’éclairer certains aspects méconnus de ces interactions inter-spécifiques. La pollinisation des orchidées du genre Ophrys est assurée par des mâles d'abeilles ou de guêpes solitaires qui opèrent une tentative d’accouplement (pseudocopulation) sur le labelle des fleurs. L'attraction des pollinisateurs est généralement hautement spécifique, régie par un mimétisme des signaux (chimiques, visuels, tactiles) des femelles des espèces d'insectes concernés. Malgré cette spécificité, des hybrides se forment occasionnellement en conditions naturelles, témoignant de la perméabilité partielle des barrières d'isolement reproductif entre espèces. Au cours de<p>ce programme de recherche, nous avons entrepris l’étude des interactions Ophryspollinisateurs en mettant l’accent sur trois aspects spécifiques, à savoir (i) la sélection des caractères floraux par les pollinisateurs, (ii) l'isolement reproductif entre espèces d'Ophrys sympatriques, et enfin (iii) l'évolution des caractères floraux au sein d'un complexe d'espèces-soeurs d'Ophrys associées à différents pollinisateurs. Les principaux<p>résultats de ce travail sont repris ci-dessous, ponctués de références aux articles qui rassemblent l’intégralité des études réalisées. / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

Understanding how floral traits covary with one another and with mating patterns is an important step in understanding how and why mating systems evolve. I examined the evolution of floral and mating system variation in Camissoniopsis cheiranthifolia (Onagraceae), a species that exhibits divergence in key floral traits expected to be associated with variation in the relative importance of outcrossing vs. self-fertilization. I combined geographic surveys of floral variation with genetic estimates of the proportion of seeds outcrossed (t) and confirmed that t covaried with corolla width and herkogamy in a predictable way both within and among populations. I then performed geographic surveys, manipulative experiments and genetic analyses to evaluate the potential role that; inbreeding depression (ID), interactions between flowers, pollinators and florivores, and reproductive assurance (RA) may have played in shaping and/or maintaining the geographic pattern of mating system variation in this species. The main selective factor maintaining outcrossing in large flowered (LF) populations appears to be ID, which was much stronger in LF compared to small flowered (SF) populations. These results are also consistent with purging of ID in SF populations. Increased selfing appeared to alleviate pollen limitation (PL) because it was associated with higher and less variable fruit set and reduced florivory by a microlepidopteran. However, evidence that florivores preferentially attacked larger flowers was equivocal. LF experienced stronger PL than SF populations suggesting that one condition for the evolution of selfing via RA is met in outcrossing populations. Floral emasculation experiments revealed that the timing of selfing also covaried with flower size among and within populations. SF self-pollinate before flowers open but LF do not, suggesting that selfing evolved in response to chronic outcross PL. Negative side effects of emasculation were detected which prevented a clear interpretation of the RA value of selfing. Given that much of what is known about RA comes from emasculation experiments, my results suggest that the assumptions of this approach, which are rarely verified, require more serious consideration. Taken together my results suggest that C. cheiranthifolia has evolved multiple stable mixed mating systems perhaps in response to selection for RA. / Thesis (Ph.D, Biology) -- Queen's University, 2012-12-30 14:13:46.366

La transition florale est un évènement clef dans la vie d’une plante. Chez le fraisier, la compréhension des mécanismes génétiques de cette transition est un enjeu majeur pour mieux contrôler la production de fruits. La transition florale peut être étudiée à travers la remontée florale, qui est la capacité d’une plante à fleurir tout au long de la période végétative. Le fraisier cultivé octoploïde, F. x ananassa, comme le fraisier diploïde, F. vesca, présentent des génotypes remontants capables de fleurir en continu. L’objectif de cette thèse est de comprendre le déterminisme génétique et moléculaire de la remontée florale chez Fragaria. Ce travail a montré que chez les fraisiers diploïde et octoploïde, le caractère ‘remontée florale’ est contrôlé par deux verrous génétiques différents localisés à des positions non orthologues. Chez le fraisier diploïde, le gène FvKSN responsable de la remontée florale a été identifié et code pour un homologue du répresseur floral TFL1. Chez les génotypes remontants, ce gène présente une délétion dans la partie codante conduisant à une protéine non fonctionnelle, incapable de réprimer la floraison. Chez le fraisier octoploïde, le QTL majeur détecté contrôlant la remontée florale est lié à la production de stolons de manière antagoniste, suggérant l’existence d’une région génomique où s'exerce une compétition entre multiplication végétative et la reproduction sexuée. Cette région génomique comprend plusieurs gènes candidats intéressants dont FT, activateur de la floraison.Une hypothèse suggérée par ce travail est que chez le fraisier, l’alternance entre phase végétative et phase reproductive est liée à l’équilibre entre les gènes FvKSN, homologue de TFL1, et FvFT, homologue de FT. La remontée florale serait la conséquence d’une modification de cet équilibre entre ces deux gènes en faveur du développement reproductif. / The floral transition is a key event in plant life. In strawberry, understanding the genetic mechanisms of floral transition is a major issue for better control of fruit production. This transition is studied through the continuous flowering, which is the ability to flower throughout the growing season. Both, the octoploid cultivated strawberry, F. x ananassa, as the woody diploid strawberry, F. vesca, displayed continuous flowering genotypes. The objective of this work is to decipher the genetic and molecular mechanism of the continuous flowering in Fragaria.This work has shown that in diploid and octoploid strawberry the continuous flowering is controlled by two different genetic 'keys' located at non-orthologous position. In diploid strawberry, the gene FvKSN responsible of continuous flowering was identified and encodes a homologous to the TFL1 floral repressor. In the continuous flowering genotypes, this gene has a deletion in the coding region leading to a nonfunctional protein unable to repress flowering. In the octoploid strawberry, the major QTL controlling both the recurrent flowering and the runner production was identified. These traits were antagonist, which suggests competition between vegetative propagation and sexual reproduction in this region. This genomic region contains several interesting candidate genes whose FT, an activator of flowering.A hypothesis could be proposed. In strawberry, the switch between vegetative and reproductive phase is linked to balance between two genes, FvKSN, homologous to TFL1 and FvFT homologous to FT. Continuous flowering would be the consequence of balance modification between this two genes to the benefit of floral development.

The following three chapters identify influences of the Imagist movement and the avant garde painters on the early poetry of Williams, and particularly on those poems that deal with flowers. This study is restricted to the earlier poems for several reasons, the most obvious being that Williams simply does not employ floral imagery to any extent in The Collected Later Poems. For instance, of the almost three hundred poems in The Collected Earlier Poems nearly sixty take flowers as their title or rely on floral imagery for part of their power. Nearly half that many use arboreal imagery, another prominent and important "object" in Williams' poetry, and, of course, many more use other images from the natural world. On the other hand, in The Collected Later Poems only three poems have flowers in their titles. Even in these three Williams was more interested in depicting sociological situations than in description, for his conception of poetry changed radically after the 1930's. He became convinced at that time that poetry should be serious rather than entertaining. Further, he became a staunch advocate of the "anti-poetic" theory of beauty whose chief tenet was that beauty and ugliness were part of a single whole. Nothing beautiful, like a flower, could exist without its soil of ugly, drab antecedents. James Guimond believes that this is the reason why Williams ceased presenting "his beautiful objects in splendid, static isolation from time and the world around them" (1, p. 50). Possibly 14 for these reasons the nature imagery is not nearly so dominant in these poems as in those written before 1940. Nor has the poetry of Paterson or Pictures from Breugel been included in this study. Because of the tremendous attention given them in the last five years, their nature imagery has been well covered. However, of the nature, and especially floral, imagery of the earlier poetry little has been said. Hopefully, this study will show that Williams made extensive and successful use of flowers in his poetry because they were the particular objects of the concrete world which best lent themselves to the related techniques and goals of first the Imagistic movement in poetry and later the Stieglitz school in painting.

and keywords The thesis discusses the depiction of selected plant species in Roman and Early Christian art and further shortly deals with most considerable elements of vegetable ornaments and its development. The diploma work turns to symbolic meaning of the plants in connection with a religion and mythic tradition. First and second chapter pursue the depiction of herbs and trees (bushes) on mosaics, frescoes and relief-sculpture. In the third part the attention is paid to the significant elements of vegetable ornament: palmette, rosette and acanthus. Sometimes representations of plants from older period are mentioned for the sake of better explanation of their symbolic context (ancient Egypt, Greece). The thesis gathers information from writings of antique authors, in chapters dealing with Christian period from Bible and apocrypha, as well as from modern works related to the problematic. An objective of the thesis is to cover the differences in symbolic meanings of plants after an oncoming of Christianity, to determine, whether those plants were depicted onwards and in which context.

Várias podem ser as causas da variação local no sucesso reprodutivo de espécies vegetais, sendo a disponibilidade de recursos abióticos, herbivoria, polinização e dispersão de sementes comumente consideradas. Em espécies distílicas, a variação na disponibilidade de recursos abióticos pode determinar diferenças na quantidade e no período de produção das estruturas reprodutivas, e estas por sua vez podem influenciar a interação planta polinizador, modulando o comportamento de forrageio de visitantes florais. Este trabalho teve como objetivos verificar como alguns fatores poderiam determinar variação na fenologia e no sucesso reprodutivo de Psychotria suterella, uma espécie arbórea distílica comum em florestas no sudeste do Brasil. Os fatores experimentalmente investigados foram água, luz, nutrientes inorgânicos e superfície foliar. Além disto, investigamos a resposta de abelhas Bombus, B. brasiliensis e B. morio, à disponibilidade de recursos florais em quatro escalas espaciais. A variação na oferta de recursos não afetou o padrão temporal sincrônico de emissão de botões e desenvolvimento de flores dos tipos florais de P. suterella, mas condicionou alterações na quantidade das estruturas reprodutivas produzidas de forma distinta em cada tipo floral. Plantas com morfologia floral longistila parecem estar se reproduzindo sob condições ambientais limitantes, em função de responderem positivamente ao aumento na disponibilidade de recursos, enquanto plantas com morfologia floral brevistila parecem estar melhor adaptadas às condições ambientais, uma vez que responderam negativamente a todos os tratamentos. Respostas fisiológicas singulares parecem ser as responsáveis por essas diferenças. Não houve variação no número de flores, energia produzida no néctar das flores e freqüência de visitas a flores e plantas para os tipos florais de P. suterella. A oferta de energia por flor e a freqüência de visitas por flor variaram entre plantas. Bombus morio e Bombus brasiliensis responderam à variação na disponibilidade de recursos florais de P. suterella em escala espacias menores que 5m, visitando com mais freqüência plantas com maior oferta de energia, independente da disponibilidade energética na vizinhança. Porém, a freqüência de visitas média por flor não apresentou relação com a quantidade de recursos florais nas plantas, e não foi influenciada pela densidade de energia nas demais escalas, fato que deve estar relacionado à grande variação na produção de néctar entre as flores dentro de uma mesma planta. / Several factors might cause intrapopulational variation in plant reproductive success, being often mentioned abiotic resource availability, herbivory, pollination and frugivory as possible factors. In distylous species, the variation on abiotic resources availability can determine differences in quantity as well as in the moment of emisssion of reproductive structures. Those structures might influence the plant-pollinator interaction, modeling foraging behaviour of floral visitors. The aims of this study were to identify how variation in some abiotic resources change the phenology and reproductive success of Psychotria suterella, a common distylous species from Brazilian southeastern forests. We experimentally changed the amounts of light, water, inorganic nutrients and foliar surface. In addition, we measured the frequency of Bombus, B. brasiliensis and B. morio, in relation to floral density at four spatial scales. The variation in abiotic resources availability did not change the temporal pattern of flowering in both, pin and thrum morphs, although bud and flower number was different. Pin plants seemed to be under restrict environmental conditions because the addition of resources increased the number of reproductive structures. On the other hand, any alteration in environmental resources affected negativelly thrum plants. We did not register variation in flower number, energy production in nectar, plant and flower visitation rates for both P. suterella floral morphs. Energy supply per flower and flower visitation rates varied among plants. Bombus morio and Bombus brasiliensis responded to availabitity of floral resources in spatial scales smaller than five meters, visiting more frequently plants with more energy reward regardless of neighbourhood energetic availability. The flower visitation rate was not related to flower resource availability in P. suterella plants. This result might be determined by the high variation in flower energy production within plant.

The Euphorbiaceae are notable for floral and inflorescence diversity and evolutionary complexity. Croton, is the second largest genus in the family and exhibits particular diversity in its flowers, especially regarding perianth and number of stamens, besides the inflorescences, which are also very diverse. Considering Croton\'s great variability in the reproductive structures, the aim of this thesis was to study flowers and inflorescences with an evolutionary approach, including morphology, ontogeny, vasculature, auxin regulation and genetic expression. Flowers in several stages of development were analyzed using light microscopy and scanning electron microscopy. Inflorescences were analyzed in stereomicroscope and the traits were plotted on the most recent phylogeny of the genus. The genetic expression was tested using RNAseq. In the first chapter the flowers showed similarity in the initiation of sepals and the presence of filamentous, petaloid structures in Croton lundianus (Didr.) Müll. Arg., interpreted here as staminodes. In Croton sphaerogynus Baill., staminodes were described for the first time. The staminodes reported here could be interpreted as transitional structures that we considered as evolutionary reductions. In the second chapter, the staminate flowers showed polystemonous androecium and the delay in petals\' initiation and the antesepalous nectaries development interfered in the development of the stamens, characterizing obdiplostemony. Vasculature corroborated obdiplostemony and revealed a central stamen in C. fuscescens with carpelar features, interpreted here as a homeosis case. Glandular staminodes were registered and interpreted as a heterotopy case. The obdiplostemony may be related to modulation of the free IAA concentrations during floral developmental steps and Croton flowers can be used as good models for obdiplostemony, homeosis and heterotopy. In the third and fourth chapter we studied Croton inflorescences, which showed 17 patterns with differences on the organization and distribution of pistillate flowers. The inflorescence traits analyzed were very homoplastic, most likely determined by convergent evolution in distantly related lineages distributed in similar habitats. The genetic expression of C. fuscescens was particularly analyzed and the transcriptome showed that the different zones have their development guided through the same transcripts set. Each zone has different expression level and these variations and gradient could be interpreted as the boundary between each inflorescence zone. The floral developmental novelties and evolutionary links identified here raise the importance of future floral studies with the genus, what would bring a better understanding on how the reproductive structures evolved in the history of the group / Euphorbiaceae é uma família que recebe destaque quanto à diversidade de flores e inflorescências, além de sua complexidade evolutiva. Croton L. é o segundo maior gênero da família e exibe particular diversidade floral, em especial quanto a o perianto e número de estames, além das inflorescências, que também se apresentam muito diversas. Considerando a grande variação nas estruturas reprodutivas de Croton, o objetivo desta tese foi estudar as flores e inflorescências com abordagem evolutiva, incluindo morfologia, ontogênese, vascularização, regulação hormonal e expressão gênica. Flores em diversos estágios de desenvolvimento foram analisadas em microscopia der luz e varredura. Inflorescências foram estudadas em estereomicroscópio e os caracteres observados foram analisados nas filogenias mais recentes do grupo. A expressão gênica foi analisada com a técnica RNAseq. No primeiro capítulo as flores apresentaram semelhanças na iniciação das sépalas e presença de filamentos, estruturas petaloides em Croton lundianus (Didr.) Müll. Arg., interpretadas como estaminódios. Em Croton sphaerogynus Baill., estaminódios foram descritos pela primeira vez. Estas estruturas podem ser interpretadas como estruturas de transição evolutiva e reduções florais. No segundo capítulo as flores estaminadas apresentaram androceu polistêmone e o retardo na iniciação das pétalas e o desenvolvimento antessépalo dos nectários foram considerados como fatores chave para o desenvolvimento do androceu como obdiplostêmone. A vascularização corroborou a obdiplostemonia e revelou um estame central com características carpelares em C. fuscescens, interpretado aqui como um caso de homeose. Nectários glandulares foram registrados e interpretados como uma mudança heterotópica. A obdiplostemonia pode estar relacionada com as diferentes concentrações de auxina ao longo das etapas de desenvolvimento e as flores de Croton podem ser consideradas como bons modelos de obdiplostemonia, homeose e heterotopia. No terceiro e quarto capítulo nós investigamos as inflorescências de Croton, que apresentaram 17 padrões com diferenças na organização e distribuição das flores pistiladas especialmente. Os caracteres das inflorescências se mostraram homoplásticos e provavelmente determinados por evolução convergente em linhagens distantes distribuídas em habitats semelhantes. A expressão gênica de C. fuscescens foi particularmente analisada e o transcriptoma demonstrou que o desenvolvimento das diferentes zonas é regulado pelo mesmo conjunto gênico. Cada zona, pistilada ou estaminada, apresenta níveis distintos de expressão diferencial e o gradiente na expressão pode ser o delimitador entre as zonas. Os novos relatos quanto ao desenvolvimento floral em Croton e os links evolutivos identificados nesta tese levanta a importância de estudos para uma melhor compreensão sobre a evolução das estruturas reprodutivas neste grupo tão importante

Brazil is the largest citrus producer in the world and has a large global citrus market share. However, several diseases affect the crop, being postbloom fruit drop (PFD) one of them. PFD has gained importance in São Paulo State for the displacement of citrus areas to regions with weather conditions more favorable for this disease. The accurate identification of the causal agent of the PFD has been performed and it was renamed as Colletotrichum abscissum. The origin of the initial inoculum is still an enigma for PFD epidemics and the hypotheses that the initial inoculum could be present in propagation material have been discussed but it has never been demonstrated. The objective of this work was to detect and quantify Colletotrichum abscissum from citrus leaves of budwood increase block and citrus nursery plants by qPCR. Four commercial citrus farms from São Paulo State, Brazil with budwood increase block and citrus nursery plants of Pera and Valencia sweet orange varieties were used for this work. C. abscissum was detected in budwood increase block and in nursery plant in both varieties (Valencia and Pera) at the four farms sampled. Out of 122 budwood increase block samples, 89 (73%) were positive for C. absicissum. From nursery plants, out of 175 samples, 129 (73%) were detected with the pathogen. The majority of the positive samples of budwood increase blocks and nursery plants contained 10 to 200 and 10 to 400 conidia of C. absicissum, respectively. With the methods used was not possible to isolate the fungus from vegetative material. This finding suggests a new long distances dispersion type of C. abscissum in the cycle of postbloom fruit drop by propagation material. Confirmation of C. abscissum in budwood increase block and nursery plants would lead to update regulations for the production of certified citrus nursery trees and searching for new control strategies of the pathogen. / O Brasil é o maior produtor de citros do mundo e possui uma grande participação no mercado global de citros. No entanto, várias doenças afetam a cultura, sendo uma delas a podridão floral dos citros (PFC). PFC ganhou importância no Estado de São Paulo pelo deslocamento de áreas de citros para regiões com condições climáticas mais favoráveis para a doença. A identificação precisa do agente causal do PFC foi realizada, tendo sido renomeado como Colletotrichum abscissum. A origem do inóculo inicial ainda é um enigma para as epidemias de PFC e as hipóteses do que o inóculo inicial poderia estar presente no material de propagação já foram discutidas, mas nunca foram demonstradas. O objetivo deste trabalho foi detectar e quantificar Colletotrichum abscissum em folhas de borbulheiras e mudas de citros por meio de qPCR. Neste trabalho, foram utilizadas quatro fazendas comerciais de citros do Estado de São Paulo, Brasil, com borbulheiras e viveiros de mudas de citros das variedades laranja Pera e Valência. C. abscissum foi detectado em borbulheiras e em mudas em ambas as variedades (Valência e Pêra) nas quatro fazendas amostradas. Das 122 amostras de folhas de borbulheiras, 89 (73%) foram positivas para C. absicissum. Das 175 amostras de folhas de mudas de citros, 129 (73%) foram detectadas com o patógeno. A maioria das amostras positivas de borbulheiras e mudas de citros continham 10 a 200 e 10 a 400 conídios de C. absicissum, respectivamente. Com os métodos utilizados, não foi possível isolar o fungo do material vegetativo. Esta descoberta sugere um novo tipo de dispersão a longas distâncias de C. abscissum no ciclo de podridão floral dos citros por meio do material de propagação. A confirmação de C. abscissum nas borbulheiras e mudas de citros levaria à atualização da regulamentação para a produção de mudas de citros certificadas e à busca de novas estratégias de controle do patógeno.