As bromeliáceas são plantas ornamentais tropicais com uma grande diversidade de cores e formas que as tornam extremamente apreciadas. Os estudos da biologia floral, associado aos sistemas reprodutivos das espécies vegetais, são de fundamental importância para subsidiar a condução de programas de melhoramento genético e conservação de espécies, além de auxiliar na determinação do grau de compatibilidade entre genótipos e eventuais barreiras reprodutivas. O objetivo da presente tese é estudar aspectos da biologia floral e reprodutiva, conservação dos grãos de pólen, estudos de compostos voláteis em flores e hibridação interespecífica e intergenérica em Bromeliaceae com potencial ornamental. Foi observada grande variabilidade genética entre as espécies estudadas, no que diz respeito à morfologia dos grãos de pólen e estigma. Altas taxas de germinação e viabilidade polínica foram obtidas para as diferentes espécies, e a receptividade do estigma está relacionada com a antese. Essas características associadas têm grande importância para a fertilização e, consequentemente, para a produção de sementes, desta forma são essenciais para a produção de híbridos e conservação de espécies. Para a conservação dos grãos de pólen, o melhor resultado foi obtido com a desidratação prévia por 3 h em sílica e conservação em nitrogênio líquido (-196°C). A partir de flores de treze espécies, foram identificados 71 compostos voláteis, alguns deles com importância na indústria de alimentos, cosméticos, perfumes, indústria química e farmacêutica. Dentre as dezessete espécies estudadas, mais de 50% apresentaram autoincompatibilidade, e algumas apresentaram autogamia, demonstrando que essas espécies apresentam autopolinização espontânea. Agamospermia foi observada em apenas duas espécies. Noventa e cinco combinações entre 17 espécies de Aechmea e Ananas (Bromelioideae) e Alcantarea e Vriesea (Tillandsioideae) foram realizadas. O sucesso nas hibridações corresponde a 33,74%, sendo que 24,96% envolveram as variedades botânicas do gênero Ananas. Entre as hibridações intergenéricas, apenas duas combinações foram obtidas com sucesso: V. michaelii x Al. nahoumii e V. simplex x Al. nahoumii. As possíveis causas da autoincompatibilidade e incongruência nesses cruzamentos estão relacionadas a diferentes eventos no tubo polínico, como: deposição irregular de calose no tubo polínico; enovelamento dos tubos polínicos no estilete; paralisação do crescimento do tubo polínico no estilete, entre outros. Sugere-se que a autoincompatibilidade seja gametofítica, evitando a autofertilização. Estudos mais aprofundados contribuirão para caracterizar as causas e as potenciais medidas para superar a autoincompatibilidade. Os resultados aqui apresentados trazem contribuições importantes para estudos de hibridação em Bromeliaceae, visando à obtenção de novidades para o mercado de plantas ornamentais, bem como contribuições para a caracterização e conservação de espécies dessa importante família / Bromeliads are tropical ornamental plants with a wide variety of colors and shapes that make them widely and extremely appreciated. The study of aspects of the floral biology, associated with the reproductive systems of these species are of fundamental importance for breeding and species conservation programs, assisting in the determination of the degree of compatibility between combination of genotypes, as well as potential reproductive barriers. The aim of this research is to study aspects of floral and reproductive biology, conservation of pollen grains, studies of volatile compounds in flowers and intergeneric and interspecific hybridization in Bromeliaceae with ornamental potential. High genetic variability was observed among the species studied, regarding the morphology of the pollen grains and stigma. High rates of germination and pollen viability were observed for the different species, and stigma receptivity showed the highest at anthesis. These characteristics are of great importance for fertilization and further seed production, thus are essential for the production of hybrids and species conservation. Preservation of pollen grains, showed the best results with a 3 h dehydration pre-treatment in silica and conservation in liquid nitrogen (-196°C). A large number of volatile compounds, totally 71, were identified from flowers of thirteen species. Some of these compounds have already been shown to be important in the food industry, cosmetics, perfumes, chemical and pharmaceutical industry. Among the seventeen species, more than 50% presented selfincompatibility and some species presented autogamy, demonstrating that these species present spontaneous self-pollination. Agamospermy was observed in only two species. Ninety-five combinations among 17 species of Aechmea and Ananas (Bromelioideae) and Alcantarea and Vriesea (Tillandsioideae) were performed, with a 33.74% rate of success, with 24.96% involving the botanical varieties of Ananas. Only two, among the intergeneric combinations, were successful, V. michaelii x Al nahoumii and V. simplex x Al nahoumii. Possible causes of self-incompatibility and incongruity in these combinations were related to different events during pollen tube growth, such as the irregular deposition of callose in pollen tubes; entangled pollen tubes in the style; arrest of pollen tube growth in the style, among others. We suggest that the self-incompatibility is gametophytic, preventing selffertilization. Further studies will help to characterize the causes and potential measures to overcome self-incompatibility. The results provide important contributions to studies of hybridization in bromeliads, aiming to produce new hybrids for the ornamental plants market, as well as contributions to the characterization and conservation of this important family of plants

<p>I combined comparative and experimental studies in the field and in the greenhouse to examine factors influencing reproductive success in two insect-pollinated herbs, the tristylous, selfincompatible perennial <i>Lythrum salicaria</i> and the self-compatible, biennial <i>Pedicularis palustris</i>. More specifically, I explored (i) the effects of plant population characteristics on the intensity and outcome of interactions with pollinators and seed predators, (ii) whether flower morphology affects duration of stigma receptivity, and (iii) whether damage-induced reduction in floral display reduces pollinator visitation and increases pollen limitation.</p><p>As predicted, the rate of pollinator visitation tended to increase and the number of flowers probed per plant tended to decrease with increasing population size in <i>L. salicaria</i>, but these relationships only approached statistical significance. By taking advantage of the pollen size polymorphism that is typical of many heterostylous plants, I could show that the number of compatible pollen grains received increased with population size, and that this was associated with a reduction in pollen limitation and increased seed output per flower. The deposition of high numbers of incompatible conspecific and heterospecific pollen grains did not appear to reduce seed set.</p><p>In <i>P. palustris</i>, fruit set and seed predation varied markedly among populations and years, but this variation could only partly be explained by variation in population size. Fruit set was positively related to population size, and seed predation was negatively related to population size, in one of three years. Similarly, the level of pollen limitation, which was quantified in two years, varied among populations, but was not related to population size, density or isolation.</p><p>In <i>L. salicaria</i>, both the duration of stigma receptivity and the effect of prior self-pollination on seed output varied among style morphs. These differences may contribute to morph-specific differences in pollen limitation and seed production documented in the field.</p><p>The results of a field experiment demonstrated that damage to the shoot apex may markedly reduce fruit production in <i>L. salicaria</i>, and suggested that this is mainly because damage reduces flower number. I found no evidence that a reduced floral display increased the severity of pollen limitation.</p><p>Taken together, the results show that interactions with both pollinators and herbivores may markedly affect reproductive output in the two plant species, and that the intensity of both mutualistic and antagonistic interactions vary considerably in space and time. Moreover, they are consistent with the hypothesis that pollination success should depend less on population size in selfcompatible than in self-incompatible plants.</p>

I combined comparative and experimental studies in the field and in the greenhouse to examine factors influencing reproductive success in two insect-pollinated herbs, the tristylous, selfincompatible perennial Lythrum salicaria and the self-compatible, biennial Pedicularis palustris. More specifically, I explored (i) the effects of plant population characteristics on the intensity and outcome of interactions with pollinators and seed predators, (ii) whether flower morphology affects duration of stigma receptivity, and (iii) whether damage-induced reduction in floral display reduces pollinator visitation and increases pollen limitation. As predicted, the rate of pollinator visitation tended to increase and the number of flowers probed per plant tended to decrease with increasing population size in L. salicaria, but these relationships only approached statistical significance. By taking advantage of the pollen size polymorphism that is typical of many heterostylous plants, I could show that the number of compatible pollen grains received increased with population size, and that this was associated with a reduction in pollen limitation and increased seed output per flower. The deposition of high numbers of incompatible conspecific and heterospecific pollen grains did not appear to reduce seed set. In P. palustris, fruit set and seed predation varied markedly among populations and years, but this variation could only partly be explained by variation in population size. Fruit set was positively related to population size, and seed predation was negatively related to population size, in one of three years. Similarly, the level of pollen limitation, which was quantified in two years, varied among populations, but was not related to population size, density or isolation. In L. salicaria, both the duration of stigma receptivity and the effect of prior self-pollination on seed output varied among style morphs. These differences may contribute to morph-specific differences in pollen limitation and seed production documented in the field. The results of a field experiment demonstrated that damage to the shoot apex may markedly reduce fruit production in L. salicaria, and suggested that this is mainly because damage reduces flower number. I found no evidence that a reduced floral display increased the severity of pollen limitation. Taken together, the results show that interactions with both pollinators and herbivores may markedly affect reproductive output in the two plant species, and that the intensity of both mutualistic and antagonistic interactions vary considerably in space and time. Moreover, they are consistent with the hypothesis that pollination success should depend less on population size in selfcompatible than in self-incompatible plants.

Sicyos deppei G. Don (Cucurbitaceae) is an invasive monoic annual tendril-bearing vine; it is endemic to Mexico, adapted to the rainfall cycle (June through the end of September) and produces spiny, single seeded fruits. Under serious infestation conditions, S. deppei grows extensively, covering native plants, crops and tree trunks. This study determined the breeding system and pollinators of S. deppei growing in three study sites at urban gardens and disturbed sites at the Campus of the Universidad de las Américas, Puebla in the city of San Andrés Cholula, Puebla (Mexico). Each female inflorescence had an average of 17 flowers at the three study sites. As a step prior to experiments, the timing for stigma receptiveness and pollen viability was determined with the Peroxtesmo KO test (PKO) and Diaminobenzidine test (DAB),respectively. Stigmas of female flowers reach maximum receptivity when flowers are at anthesis; receptivity decreases as the flower reaches the succeeding floral stages. Viability of pollen grains increases with flower development; viabilitypercentages at early stages of floral development are very low, as opposed to the higher percentages of pollen viability found in flowers at anthesis and following developmental stages. Breeding systems were tested for xenogamy and geitonogamy by hand pollinating female flowers. Breeding systems results demonstrated that S. i deppei has a mixed-mating system, being able to set fruit and seed when pollinated with pollen from different plants and from pollen of the same plants. The pollinators were determined with the single-visit method. The diversity of floral visitors in this study was low; the most effective pollinator for S. deppei in this study was Apis mellifera. Throughout the rainy season, this study also described the phenology of S. deppei at the plant and flower level, as well as total plant length. Each stage of development in male and female flowers lasts one day. At the end of the rainy season (N2010) individual plants measured between 947 and 270 cm. / CONACYT, NSERC-CANPOLIN

As bromeliáceas são plantas ornamentais tropicais com uma grande diversidade de cores e formas que as tornam extremamente apreciadas. Os estudos da biologia floral, associado aos sistemas reprodutivos das espécies vegetais, são de fundamental importância para subsidiar a condução de programas de melhoramento genético e conservação de espécies, além de auxiliar na determinação do grau de compatibilidade entre genótipos e eventuais barreiras reprodutivas. O objetivo da presente tese é estudar aspectos da biologia floral e reprodutiva, conservação dos grãos de pólen, estudos de compostos voláteis em flores e hibridação interespecífica e intergenérica em Bromeliaceae com potencial ornamental. Foi observada grande variabilidade genética entre as espécies estudadas, no que diz respeito à morfologia dos grãos de pólen e estigma. Altas taxas de germinação e viabilidade polínica foram obtidas para as diferentes espécies, e a receptividade do estigma está relacionada com a antese. Essas características associadas têm grande importância para a fertilização e, consequentemente, para a produção de sementes, desta forma são essenciais para a produção de híbridos e conservação de espécies. Para a conservação dos grãos de pólen, o melhor resultado foi obtido com a desidratação prévia por 3 h em sílica e conservação em nitrogênio líquido (-196°C). A partir de flores de treze espécies, foram identificados 71 compostos voláteis, alguns deles com importância na indústria de alimentos, cosméticos, perfumes, indústria química e farmacêutica. Dentre as dezessete espécies estudadas, mais de 50% apresentaram autoincompatibilidade, e algumas apresentaram autogamia, demonstrando que essas espécies apresentam autopolinização espontânea. Agamospermia foi observada em apenas duas espécies. Noventa e cinco combinações entre 17 espécies de Aechmea e Ananas (Bromelioideae) e Alcantarea e Vriesea (Tillandsioideae) foram realizadas. O sucesso nas hibridações corresponde a 33,74%, sendo que 24,96% envolveram as variedades botânicas do gênero Ananas. Entre as hibridações intergenéricas, apenas duas combinações foram obtidas com sucesso: V. michaelii x Al. nahoumii e V. simplex x Al. nahoumii. As possíveis causas da autoincompatibilidade e incongruência nesses cruzamentos estão relacionadas a diferentes eventos no tubo polínico, como: deposição irregular de calose no tubo polínico; enovelamento dos tubos polínicos no estilete; paralisação do crescimento do tubo polínico no estilete, entre outros. Sugere-se que a autoincompatibilidade seja gametofítica, evitando a autofertilização. Estudos mais aprofundados contribuirão para caracterizar as causas e as potenciais medidas para superar a autoincompatibilidade. Os resultados aqui apresentados trazem contribuições importantes para estudos de hibridação em Bromeliaceae, visando à obtenção de novidades para o mercado de plantas ornamentais, bem como contribuições para a caracterização e conservação de espécies dessa importante família / Bromeliads are tropical ornamental plants with a wide variety of colors and shapes that make them widely and extremely appreciated. The study of aspects of the floral biology, associated with the reproductive systems of these species are of fundamental importance for breeding and species conservation programs, assisting in the determination of the degree of compatibility between combination of genotypes, as well as potential reproductive barriers. The aim of this research is to study aspects of floral and reproductive biology, conservation of pollen grains, studies of volatile compounds in flowers and intergeneric and interspecific hybridization in Bromeliaceae with ornamental potential. High genetic variability was observed among the species studied, regarding the morphology of the pollen grains and stigma. High rates of germination and pollen viability were observed for the different species, and stigma receptivity showed the highest at anthesis. These characteristics are of great importance for fertilization and further seed production, thus are essential for the production of hybrids and species conservation. Preservation of pollen grains, showed the best results with a 3 h dehydration pre-treatment in silica and conservation in liquid nitrogen (-196°C). A large number of volatile compounds, totally 71, were identified from flowers of thirteen species. Some of these compounds have already been shown to be important in the food industry, cosmetics, perfumes, chemical and pharmaceutical industry. Among the seventeen species, more than 50% presented selfincompatibility and some species presented autogamy, demonstrating that these species present spontaneous self-pollination. Agamospermy was observed in only two species. Ninety-five combinations among 17 species of Aechmea and Ananas (Bromelioideae) and Alcantarea and Vriesea (Tillandsioideae) were performed, with a 33.74% rate of success, with 24.96% involving the botanical varieties of Ananas. Only two, among the intergeneric combinations, were successful, V. michaelii x Al nahoumii and V. simplex x Al nahoumii. Possible causes of self-incompatibility and incongruity in these combinations were related to different events during pollen tube growth, such as the irregular deposition of callose in pollen tubes; entangled pollen tubes in the style; arrest of pollen tube growth in the style, among others. We suggest that the self-incompatibility is gametophytic, preventing selffertilization. Further studies will help to characterize the causes and potential measures to overcome self-incompatibility. The results provide important contributions to studies of hybridization in bromeliads, aiming to produce new hybrids for the ornamental plants market, as well as contributions to the characterization and conservation of this important family of plants