Orientador: Marlies Sazima / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-16T08:56:09Z (GMT). No. of bitstreams: 1 Brito_ViniciusLourencoGarcia_M.pdf: 8743517 bytes, checksum: efdc732f7b02ccea2c628acf24677361 (MD5) Previous issue date: 2010 / Resumo: As montanhas apresentam alta diversidade e diferentes condições ambientais ao longo de curtas distâncias. Assim, as montanhas são ideais para estudos ecológicos e evolutivos que podem somar valores e aprimorar projetos de conservação. Em altitudes elevadas as condições ambientais podem reduzir a quantidade de polinizadores, principalmente de abelhas. Desta forma, em espécies estritamente melitófilas, características como a fenologia, o sistema reprodutivo, o fluxo de pólen e a estrutura genética das populações pode variar ao longo do gradiente, uma vez que a transferência de grãos de pólen aos estigmas co-específicos também varia ao longo do gradiente. No caso de áreas de elevada altitude, a transferência de pólen é limitada (limitação de pólen), reduzindo as possibilidades de polinização cruzada. O presente estudo tem por objetivo obter informações sobre a biologia da polinização, reprodução e genética de duas populações de Tibouchina pulchra (Melastomataceae) ocorrentes em duas áreas de gradiente altitudinal: Núcleo Santa Virgínia (NSV) e Núcleo de Desenvolvimento Picinguaba (NDP) do Parque Estadual da Serra do Mar. Foram feitas observações mensais para definir padrões e estratégias de floração, registrar dados sobre a biologia floral e reprodutiva, além de verificar a riqueza e abundância dos polinizadores e caracterizar as interações dessa espécie com as abelhas visitantes. Material genético de 44 indivíduos do NSV e 45 indivíduos do NDP foram coletados para o desenvolvimento e caracterização de 12 loco microssatélites polimórficos e estes foram utilizados para fazer análises de agrupamento, ordenação bayesiana e medidas de diversidade genética nas duas populações. Os aspectos da biologia reprodutiva são diferentes entre as duas áreas: na área elevada a florada é mais intensa, a produção de pólen é menor, há limitação na transferência de pólen, mas a fertilização de sementes provindas de polinização cruzada manual é maior. Na outra área são produzidos mais frutos e há maior riqueza e abundância de polinizadores. Ocorre diferenciação genética entre as populações, mas com uma interface de contato entre elas, além de menor diversidade genética na população da área elevada. Estes resultados indicam que a ausência de polinizadores na região de altitude elevada está associada a diferentes estratégias na biologia floral e reprodutiva para balancear a limitação de pólen. Além disso, diferentes dinâmicas de fluxo gênico mediado pelo pólen nas duas populações e as características de distribuição e reprodução podem influenciar a estrutura e a diversidade genética de Tibouchina pulchra ao longo da Serra do Mar / Abstract: Mountains have high diversity and many environmental conditions at short distances. Hence, they are an ideal place to develop ecological and evolutionary studies that can improve conservation projects. At high altitudes, the environmental conditions reduce pollinator abundance, mainly bees. Therefore, traits such as phenology, breeding system and genetic structure of plant populations pollinated by bees could vary in an altitudinal gradient, because pollen grain transference to co-specific flowers varies also. At high altitudes pollen transference is limited (pollen limitation) reducing cross-pollination. The main goal of the present study was to obtain information about pollination biology, breeding system and genetic structure of two populations of Tibouchina pulchra (Melastomataceae) that occur in two different areas of an altitudinal gradient: Núcleo Santa Virgínia (NSV) and Núcleo de Desenvolvimento Picinguaba (NDP) of Parque Estadual da Serra do Mar. Field work was done monthly to describe the flowering patterns and strategies, record floral and reproductive biology, verify pollinator diversity and characterize the interactions among this plant species and bee visitors. Genetic material was collected from 44 Tibouchina pulchra individuals of NSV and 45 individuals of NDP to developed and characterize 12 microsatellite polymorphic loci, which were used to analyze population's genetics by different methods. At the higher area the plants have greater flowering intensity, the flowers produce less pollen grains and the stigmas receive less pollen, but set more seeds after manual cross pollination than individuals at the lower area, where pollinator diversity is higher and plants produce more fruits. There is genetic differentiation, but also an interface contact between the two populations. The population at higher altitude has less genetic diversity than the one at lower altitude. The lack of pollinators at the higher area is associated with different floral and reproductive strategies to compensate pollen limitation. Moreover the genetic structure and diversity respond to different dynamics of pollen flow and the patterns of distribution and reproduction of Tibouchina pulchra at the altitudinal gradient of Serra do Mar / Mestrado / Biologia Vegetal / Mestre em Biologia Vegetal

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

Phenotypic plasticity plays an important role in organisms’ adaptability to environmental change such as global warming caused by greenhouse-gas emissions. One plastic response to increased temperatures is for organisms to shift their phenology. It is of great concern that the phenologies of interacting species, such as plants and pollinators, may be shifting at different rates, causing temporal mismatches, which for plants can lead to unsuccessful reproduction. The “reproductive assurance hypothesis” states that plants capable of self-pollination should be under high selection to employ this as their main reproductive strategy in the event of pollinator scarcity to ensure reproduction, and consequently invest less in attracting pollinators. This study examines how soil warming in the Hengill geothermal area in Iceland affects the flowering phenology, reproductive strategy and investment in attractiveness to pollinators in the self-compatible herb Cerastium fontanum (Caryophyllaceae), when grown in a common garden in Stockholm, Sweden. Previous research showed that C. fontanum from warmed soils flowered earlier in situ than plants from colder soils, and later when grown in a common environment. In this study, C. fontanum plants collected along a temperature gradient followed the same counter-gradient pattern, where plants from warmer soils flowered later than plants from colder soils. Soil temperature at site of origin positively affected flower number but had no effect on flower size, seed production from autogamous self-pollination or visitation rate. Based on my findings it does not appear that C. fontanum, despite having an earlier flowering phenology in situ, is under any selection to alter its reproductive strategy or investment in attractiveness to pollinators when grown in a common temperature, and therefore it seems unlikely that plants are experiencing a temporal mismatch with insect pollinators. However, it would be worthwhile to conduct a similar experiment in Iceland to better understand how an earlier flowering affects pollination systems.

Les changements globaux récents affectent la physiologie, la distribution et la phénologie des espèces, ainsi que la dynamique des populations et les interactions entre espèces. Les interactions plantes-pollinisateurs sont particulièrement menacées par les changements globaux et la perturbation de ces interactions peut avoir des conséquences importantes sur le système de reproduction des espèces végétales. Dans ce contexte des changements globaux, nous avons déterminé les cortèges de visiteurs de Rhododendron ferrugineum le long de gradients environnementaux et étudié comment la variabilité de leur efficacité affectait le système de reproduction de cette espèce. Nous nous sommes également intéressés à l’histoire biogéographique de cette espèce et comment elle a répondu à des changements passés tels que les dernières glaciations. Nous avons mis en évidence que R. ferrugineum est visité par une large diversité d’espèces d’insectes. L’efficacité des cortèges de visiteurs varie le long de gradients environnementaux mais ne semble pas avoir un impact sur le système de R. ferrugineum. Cette espèce présente un système mixte de reproduction, avec une capacité à l’autofécondation mais les taux élevés de dépression de consanguinité limitent le développement des individus issus d’autofécondation. Cette forte dépression de consanguinité a permis un maintien relativement élevé de la diversité génétique dans les Pyrénées. Un tel niveau de dépression de consanguinité ne permet pas l’évolution de l’autofécondation et maintient ainsi le système mixte de reproduction chez R. ferrugineum. La capacité d’autofécondation de R. ferrugineum pourrait lui permettre de coloniser de nouveaux milieux ou de survivre aux changements globaux. Durant les dernières glaciations, R. ferrugineum a survécu dans de grands refuges de basse altitude ainsi que dans des nunataks (refuges de haute altitude). Quelques populations marginales présentent un taux significatifs de consanguinité (FIS> 0) et des niveaux de diversité génétique particulièrement faibles. Ce patron génétique est consistant avec des évènements de fondation accompagnés de perte de diversité génétique et d’hétérozygotie durant les périodes d’expansion de l’aire de répartition de l’espèce. Ces données suggèrent que la dépression de consanguinité dans ces populations devait être faible et que l’assurance reproductive a joué un rôle fondamental dans l’établissement de ces populations. / Recent global changes affect the physiology, distribution and phenology of species, also they impact population dynamic and interactions among species. Plantpollinators interactions are particularly threated by global changes and perturbations of these interactions may lead to important changes in plant mating system. In this context of globalchanges, we determined the pollinator assemblages of Rhododendron ferrugineum and howthe variability of their efficiencies affects the mating system. We also studied thebiogeographic history of R. ferrugineum and how it responds to past climatic changes.We have shown that R. ferrugineum is visited by a large variety of insects. Visitorassemblages efficiency varied along environmental gradients but did not seem to impact themating system of R. ferrugineum. This species presents a mixed mating system, indeed it isable to self-fecundate but high levels of inbreeding depression are limiting the development of self-fecundate descendants. High levels of inbreeding depression maintain high genetic diversity in the Pyrenees. Also, it did not allow the evolution of selfing and maintain a mixed mating system. The ability to self-fecundate may favor the colonization of new habitats.During the last glaciation, R. ferrugineum survived in large lowland refugia and in nunataks at high altitude. Some marginal populations present a high level of selfing (FIS> 0) and low genetic diversity. This genetic pattern is consistent with foundation events and loss of genetic diversity and heterozygosity along colonization rods. Our data suggest that inbreeding depression in these populations should have been low and the reproductive assurance played akey role in the establishment of these populations.