Título:	Efeito da amplitude de distribuição geográfica nos traços reprodutivos e citogenéticos em Angiospermas do Cerrado
Autor(es):	Silveira, Andressa Dantas da
Orientador(es):	Proença, Carolyn Elinore Barnes
Assunto:	Diploidia Poliploidia Endemismo Reprodução vegetal
Data de publicação:	13-Mai-2022
Data de defesa:	17-Dez-2021
Referência:	SILVEIRA, Andressa Dantas da. Efeito da amplitude de distribuição geográfica nos traços reprodutivos e citogenéticos em Angiospermas do Cerrado. 2021. 123 f., il. Tese (Doutorado em Botânica) — Universidade de Brasília, Brasília, 2021.
Abstract:	Life processes that occur at distributional levels include speciation, extinction and changes in geographic distribution ranges. This study looks at a few of the ecological and environmental factors that affect the distributional range of plant species in the Cerrado biome. In Chapter 1 we performed chromosome counts for 12 narrow endemic species that are occur only in Cerrado to fill knowledge gaps in ciyological knowledge. The new chromosome counts found were: Cuphea cunninghamiifolia 2n=16, Diplusodon adpressipilus, D. leucocalycinusand D. rosmarinifolius2n=30, Eremanthus veadeiroensis 2n = 34, Manihot appaniiand M. purpureo-costata2n=36, Myrcia rhodeosepala and Psidium ratterianum 2n=22,Mimosa venatorum 2n=26, Oocephalus grazielae and O. niveus 2n=28. The counts recorded were the first for these species and match numbers previously found in their respective genera. The count found for Psidium ratterianum(2n = 22), sugesting diploidy, is rare but not unknown in this predominantly polyploid genus. These chromosome counts are important to understand the taxonomic and evolutionary relationships within groups that include both widespread and restricted, narrow-endemic and often threatened species. In Chapter 2 we analysed how cytogenetic characteristics relate to geographic distribution in the Cerrado Biome. We first investigated variation in levels of ploidy in Angiosperms of the Cerrado Biome to geographic distribution (adopting the four categories in W. Hawthorne’s star system). In this system, species are classified into four categories —black, gold, blueou greenstar—based on an evaluation of their global distribution; this is measured as how many degrees square the species occupies, with the origin of the square at the intersection of equator paralells with meridians. We also categorized habit and mode of dispersal and evaluated the response of geographic distribution to the three variables combined and to verify if the two upper and lower distributional categories can be separated (discriminated) byhabit, dispersal mode and ploidy level through binary logistic regression. Results showed that narrow endemic species are significantly associated to diploidy, and that the proportion of polyploids increase as geographic distribution became wider. We alsofound a positive correlation between polyploidy and habit: species categorized as herbs/subshrubs had a significantly higher percentage of polyploids. Our results therefore support the postulated relationship on a global, but unrefined scale, that a species ability to expand its geographic distribution is strongly influenced by its cytogenetic characteristics, i.e., by polyploidy, and that this effect is more powerful than habit or mode of dispersal. The model of Binary Logistic Regression, based on the sample of Cerrado biome species used in this study (with chromosome counts) showed that life form, mode of dispersal, and level of ploidy are possible predictors of wideness of geographic distribution in the Cerrado. The binary logistic regression model showed that habit, mode of dispersal and ploidy level explain 70% of the geographic distribution in the Cerrado when two categories are adopted. It also showed that a species chance of being a polyploid, zoochoric and a climber increases as geographic distribution increases. In Chapter 3 we investigated if the reproductive functional traits, i.e., investment in flowers and fruits, differed between close congeners with wide and narrow distribution in the Cerrado biome. We compared investment in flowers and fruits between ten pairs of phylogenetically close congeners of recent origin within six Eudicotyledon families: Asteraceae, Euphorbiaceae, Fabaceae, Lamiaceae Lythraceae, and Myrtaceae. We compared functional ecological traits, represented by investment in flowering and fruiting in ten congeneric pairs of recent origin in Eremanthus (Asteraceae), Trichogonia (Asteraceae),Manihot(Euphorbiaceae),Mimosa(Fabaceae),Oocephalus(Lamiaceae),Cuphea(Lythraceae),Diplusodon (Lythraceae)eMyrcia(Myrtaceae). Two populations per species were sampled for reproductive functionaltraits. Data spread was visualized using GLM, and congeneric populations tested for significant difference using T-tests and then Chi-square as expected frequency on the significantly different results. Tests showed that none of the two conspecific populations differed significantly from each other, so results were united. Narrow endemics did not differ in height from their widespread counterparts, but differed significantly in most of their reproductive functional traits. Narrow endemics invested more resources in flowering, producing heavier flowers (albeit less flowers per plant) than their widespread counterparts. Narrow endemics also invested more resources in fruits, producing less fruits with heavier seeds than their widespread counterparts, althoughno significant difference in seeds produced per fruit was detected.The higher investment in reproductive functional traits suggest that narrow-endemic Cerrado species are edaphic neo-endemics that survive by investing in specialization and persistence inlocalized stressful environments, rather than range expansion by diversification. It is possible that the investment in heavier flowers and fruits, as well as in heavier seeds, are characteristic of at least some species of Cerrado neoendemics. There may be selective pressure by the environment on these species, making them better adapted to persist locally, as opposed to their widespread congeners that have a more generalist strategy.
Unidade Acadêmica:	Instituto de Ciências Biológicas (IB) Departamento de Botânica (IB BOT)
Informações adicionais:	Tese (doutorado) — Universidade de Brasília, Instituto de Ciências Biológicas, Departamento de Botânica, Programa de Pós-Graduação em Botânica, 2021.
Programa de pós-graduação:	Programa de Pós-Graduação em Botânica
Licença:	A concessão da licença deste item refere-se ao termo de autorização impresso assinado pelo autor com as seguintes condições: Na qualidade de titular dos direitos de autor da publicação, autorizo a Universidade de Brasília e o IBICT a disponibilizar por meio dos sites www.bce.unb.br, www.ibict.br, http://hercules.vtls.com/cgi-bin/ndltd/chameleon?lng=pt&skin=ndltd sem ressarcimento dos direitos autorais, de acordo com a Lei nº 9610/98, o texto integral da obra disponibilizada, conforme permissões assinaladas, para fins de leitura, impressão e/ou download, a título de divulgação da produção científica brasileira, a partir desta data.
Agência financiadora:	Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES).
Aparece nas coleções:	Teses, dissertações e produtos pós-doutorado

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