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Vriesea carinata is an endemic bromeliad from the Brazilian Atlantic Forest. It has trichome and tank system in their leaves which allows to absorb water and nutrients. It belongs to Bromeliaceae family, which includes several species highly enriched of cysteine-proteases (CysPs). These proteolytic enzymes regulate processes as senescence, cell differentiation, pathogen-linked programmed cell death and mobilization of proteins. Although, their biological importance, there are not genomic resources in V. carinata that can help to identify and understand their molecular mechanisms involved in different biological processes. Thus high-throughput transcriptome sequencing of V. carinata is necessary to generate sequences for the purpose of gene discovery and functional genomic studies. In the present study, we sequenced and assembled the V. carinata transcriptome to the identification of CysPs. A total of 43,232 contigs were assembled for the leaf tissue. BLAST analysis indicated that 23,803 contigs exhibited similarity to non-redundant Viridiplantae proteins. 28.24% of the contigs were classified into the COG database, and gene ontology categorized them into 61 functional groups. A metabolic pathway analysis with KEGG revealed 9679 contigs assigned to 31 metabolic pathways. Among 16 full-length CysPs identified, 11 were evaluated in respect to their expression patterns in the leaf apex, base and inflorescence tissues. The results showed differential expression levels of legumain, metacaspase, pyroglutamyl and papain-like CysPs depending of the leaf region. These results provide a global overview of V. carinata gene functions and expression activities of CysPs in those tissues.

Plant hybridization allows for the creation of new genotypes playing a strategic role in the development of new cultivars of interest for the horticultural trade, and is a central phenomenon in plant speciation processes. We worked with a plant family known as a case of Neotropical adaptive radiation, characterizing the reproductive systems selected species. This study aimed to identify the reproductive systems of sixteen bromeliad species, and to evaluate potential reproductive barriers in interspecific and intergeneric crosses. A total of 931 interspecific and intergeneric hybridization crosses were conducted in 80 different combinations involving 16 species belonging to five genera Aechmea, Ananas, Pseudananas, Alcantarea, and Vriesea. Reproductive systems were determined by controlled pollinations, and autogamy or self-incompatibility indexes. Fluorescence microscopy was used to evaluate pollen tube growth in the pistil. Seed germination was evaluated for each treatment. Over half of the species showed evidences of self-incompatibility: Aechmea bicolor, Ae. fasciata, Ae. nudicaulis, Ananas ananassoides, An. bracteatus, An. lucidus, An. parguazensis, Vriesea carinata, and V. paraibica. Among the self-compatible species, Ae. bromeliifolia, Ae. distichantha, and Pseudananas sagenarius presented autogamy. Alcantarea nahoumii, V. friburgensis, V. michaelii, and V. simplex exhibited no autogamy thus requiring pollinators. Agamospermy was observed in Ae. bromeliifolia, and Ae. distichantha. Crosses were successful in 43% of the attempts, corresponding to 32% of the species of the Ananas genus. Among the intergeneric crosses, only V. michaelii x Al. nahoumii and V. simplex x Al. nahoumii succeeded. Possible causes of self-incompatibility and incongruity in these crosses are related to different impediments to the pollen tube growth, such as an irregular deposition of callose on pollen tube; curling and arrest of pollen tube growth in the style, among others. It is suggested that the self-incompatibility is gametophytic, avoiding self-fertilization.

Morphoanatomical characterization of the stigma of different species has provided important data for the taxonomy of Bromeliaceae. Stigma receptivity is fundamental for the effectiveness of reproduction in plants, and the production of hybrids by controlled pollination. This study aimed to characterize stigma morphoanatomy of 18 Bromeliaceae species, from five genera, by means of light and scanning electron microscopy, and to determine the stigma receptivity of these species. The species investigated were: Aechmea bicolor, Aechmea bromeliifolia, Aechmea distichantha, Aechmea fasciata, Aechmea nudicaulis, Ananas sp., Ananas ananassoides, Ananas bracteatus, Ananas lucidus, Ananas parguazensis, Alcantarea nahoumii, Pseudananas sagenarius, Vriesea carinata, Vriesea friburgensis, Vriesea michaelii, Vriesea paraibica, Vriesea simplex and Vriesea unilateralis. Three methods were used comparatively to determine stigma receptivity during floral opening: hydrogen peroxide, benzidine and α-naphthyl acetate. Two stigma types were observed: conduplicate-spiral in Aechmea, Ananas, Alcantarea and Pseudananas and convolute-blade in Vriesea. The stigma is trifid, formed by a unistratified epidermis, parenchyma with numerous idioblasts containing raphides, and three vascular bundles, one for each carpel. In the conduplicate-spiral stigmas type, the inner epidermal cells contain dense cytoplasm and a prominent nucleus, a characteristic not observed in the convolute-blade stigmas type. The stigmatic papillae vary according to species, as well as the presence of an ornamented cuticle. The longest pistil length was observed in A. nahoumii (91.75 mm) and shortest in A. bromeliifolia (4.19 mm). Higher stigma receptivity is observed at anthesis for the species studied, with the highest receptivity at 8 am and remaining receptive until noon, with the exception of V. unilateralis, for which the greatest receptivity was observed at midnight and extended until dawn. The use of α-naphthyl acetate was the most efficient methodology for the detection of stigma receptivity, and to identify the receptive areas of the stigma.

Studies on interspecific gene flow and hybridization are important for understanding speciation processes and the movement of genes across species boundaries. In sympatric areas, hybridization between closely related species can be a common phenomenon and the degree of reproductive isolation (RI) among these species is closely related to the probability of hybrid formation. Here, using 14 nuclear microsatellites and two plastid DNA regions, we investigated the occurrence of natural hybridization in four sympatric populations of Vriesea carinata and V. incurvata. We also analysed four allopatric populations (two from each species), totalling 272 samples. These species share pollinators and have sequential flowering with a short period of overlap. Based on genetic assignment tests, 17 hybrids were detected in two of the four sympatric populations studied (8.29% of the individuals sampled). Our results showed low levels of nuclear (FST = 0.098) and high plastid genetic differentiation (FST = 0.601), with no haplotype sharing between parental species. The presence of plastid DNA haplotypes of both parental species in the hybrids indicated that hybridization probably occurred in both directions. We identified few hybrids, probably in consequence of some degree of RI between these species. Several RI barriers may be acting to maintain species integrity, temporal flowering differences being one important factor.

Premise of the Study Expressed sequence tag–simple sequence repeat (EST‐SSR) markers were isolated for Vriesea carinata, an endemic bromeliad from the Brazilian Atlantic Forest. These SSR loci may be used to investigate the genetic diversity and population structure of this species and related bromeliads. Methods and Results Based on the transcriptome data of V. carinata, 30 primer pairs were designed and selected for initial validation. Of these primer pairs, 16 generated suitable SSR loci in 69 individuals. The number of alleles per locus ranged from one to 13; the levels of observed and expected heterozygosity per locus ranged from 0.000 to 1.000 and from 0.000 to 0.935, respectively. All loci produced heterologous amplification. Transferability of the loci was tested in 15 species belonging to three Bromeliaceae subfamilies. Conclusions The developed EST‐SSR markers revealed polymorphism in the four studied populations and could be useful to investigate the genetic diversity of V. carinata and related species. The markers may also be suitable for novel gene annotation and discovery.

RESUMO Com objetivo de introdução de epífitas em manejo de restauração florestal, foi avaliado o efeito da aplicação de bioestimulante no desenvolvimento de três espécies epífitas sob condição de arboreto. Plantas das espécies Vriesea carinata Wawra (Bromeliaceae), Oncidium flexuosum Sims (Orchidaceae) e Rhipsalis paradoxa (Salm-Dyck ex Pfeiff.) Salm-Dyck (Cactaceae) foram pulverizadas, com o bioestimulante Stimulate® nas concentrações de 0,0, 4,0, 8,0 e 12,0 mL L-1. Estacas de Chorisia speciosa foram utilizadas como suporte e substrato para a fixação das plantas. As variáveis analisadas foram: qualidade da fixação, número de folhas, brotos e raízes e, matéria seca da parte aérea e raízes. O delineamento experimental foi em blocos ao acaso constituído de quatro tratamentos (concentrações do bioestimulante) com três repetições de cinco plantas, totalizando 15 plantas por tratamento, para cada espécie. Os dados foram submetidos à análise de variância e regressão. Os tratamentos 4 e 8 mL L-1 de bioestimulante proporcionou aumento da produção de folhas e do diâmetro do caule de V. carinata, enquanto que as demais variáveis analisadas, nas três espécies, não apresentaram diferenças significativas entre os tratamentos. Nas condições do experimento, o bioestimulante não apresentou respostas significativas quanto ao crescimento, desenvolvimento do sistema radicular e à qualidade da fixação para as espécies estudadas; estimulando, no entanto, o crescimento da parte aérea de V. carinata e O. flexuosum. A facilidade de aplicação do bioestimulante, proporcionando o crescimento da parte aérea e o baixo custo do produto, possibilita a sua utilização no estímulo do crescimento de plantas epífitas a serem utilizadas na restauração florestal. ABSTRACT The present study evaluated the effect of biostimulant (Cytokinin as kinetin 0.009%, Gibberellic acid 0.005%, and Indole-3-butyric acid 0.005%) on the development of three epiphyte species aiming their introduction on forest restoration management. Concentrations of 0, 4, 8, and 12 mL L-1 of bioestimulant Stimulate® were applied by leaf spray on Vriesea carinata Wawra (Bromeliaceae), Oncidium flexuosum Sims (Orchidaceae), and Rhipsalis paradoxa (Salm-Dyck ex Pfeiff.) Salm-Dyck (Cactaceae). Branches of Chorisia speciosa were used as phorophyte to support the plants. The parameters quality of anchorage, number of leaves, shoots, and roots, and dry matter of the roots and shoots were analyzed. The experimental design was a randomized complete block with four treatments, three replications with five plants each, totalizing 15 plants per treatment for each species. Data were submitted to variance analysis and regression. The treatments 4 and 8 mL L-1 of biostimulant improved the number of leaves and plant diameter of V. carinata. The other parameters were not significant for the three species in all treatments evaluated. The bioestimulant on the experimental conditions had no significant responses on growth and development of roots and anchorage quality for the species, with stimulus of shoots growth on V. carinata and O. flexuosum. The growth stimulus of the shoot and the easy, fast, and low cost of the application of biostimulant, enable its use to optimize the transplanting of epiphytic plants for forest restoration.

The miRNAs play important roles in regulation of gene expression at the post-transcriptional level. A small RNA and RNA-seq of libraries were constructed to identify miRNAs in Vriesea carinata, a native bromeliad species from Brazilian Atlantic Rainforest. Illumina technology was used to perform high throughput sequencing and data was analyzed using bioinformatics tools. We obtained 2,191,509 mature miRNAs sequences representing 54 conserved families in plant species. Further analysis allowed the prediction of secondary structures for 19 conserved and 16 novel miRNAs. Potential targets were predicted from pre-miRNAs by sequence homology and validated using RTqPCR approach. This study provides the first identification of miRNAs and their potential targets of a bromeliad species.

Plant size and clonality are important traits for explaining the reproductive effort of clonal plants. Larger plants can invest more resources into reproduction, and clonality is known to increase reproductive effort. Moreover, reproductive effort is influenced by environmental variation, and so the spatial distribution of plants may affect plant reproductive effort. We investigated the effect of plant size, clonality and spatial distribution on the reproductive effort of Vriesea carinata in the Atlantic Forest in the state of Paraná, Brazil. We marked twenty individual plants and measured their rosette size, biomass and number, as well as rosette reproductive effort (number of flowers, fruits and seeds). We also evaluated the relationship between reproductive effort and spatial distribution of plants. Reproductive effort did not correlate with size, whereas greater clonal growth contributed to a lower reproductive effort because rosettes within clones that had more rosettes set fewer flowers. We found that plants growing closer to each other exhibited similar reproductive efforts independently of vegetative traits, because reproductive traits were spatially autocorrelated. In Vriesea carinata, the main drivers of reproductive effort are clonality, which decreases flower production, and spatial factors, which result in greater similarity in reproductive efforts among more proximate plants.

Visando a contribuir para o melhor entendimento da participação da atividade extrativista no âmbito da comercialização de bromélias no Brasil, apresentou-se resultado de pesquisa que buscou: a) identificar e caracterizar os extrativistas de bromélias formalmente registrados e os informais no Estado do Paraná; b) identificar e caracterizar as metodologias de coleta, o preparo e vias de comercialização das plantas coletadas; c) levantar a opinião dos extrativistas sobre facilidades e dificuldades desta atividade. O extrativismo de bromélias no Paraná foi identificado em 12 municípios, englobando 31 famílias extratoras, predominantemente concentradas no litoral do Paraná (n=10) e Município de Ortigueira (n=7). Foram identificados dois tipos básicos de extrativistas: residente e oportunista, com diferenças marcantes entre estes, especialmente no que se refere a volume e forma de extração. Foram identificadas 21 espécies submetidas ao extrativismo, sendo as mais frequentemente coletadas: Vriesea incurvata Gaudich. comercializada por 90% dos entrevistados, Nidularium innocentii Lem. (77%), Vriesea platynema Gaudich. (67%), Tillandsia stricta Sol. ex Ker Gawl. (55%) e Vriesea carinata Lem. (55%). Aiming to contribute to the better understanding of the wild harvesting participation in the context of the bromeliads trade, the results from a study focused on: a) identifying and to characterizing the bromeliads wild harvesters (formally and not formally registered) in the State of the Paraná; b) identifying and characterizing the harvesting methodologies, preparation and trade routes, and c) surveying the harvesters opinion on the facilities and difficulties of bromeliads wild harvesting are presented. The bromeliads wild harvesting was detected in 12 municipalities at Parana State, involving 31 harvester families, most of them concentrated at the coastal zone (n=10) and Ortigueira Mun. (7). Two basic harvester types were identified: resident and opportunist with outstanding differences between them especially related to volume and forms of extraction. A total of 21 bromeliads species were identified as submitted to wild harvesting, being the more frequently collected: Vriesea incurvata Gaudich. (cited by 90% of the interviewed harvesters), Nidularium innocentii Lem. (77%), Vriesea platynema Gaudich. (67%), Tillandsia stricta Sol. ex Ker Gawl. (55%) and Vriesea carinata Wawra (55%).

Premise of the Study Expressed sequence tag-simple sequence repeat (EST-SSR) markers were isolated for Vriesea carinata, an endemic bromeliad from the Brazilian Atlantic Forest. These SSR loci may be used to investigate the genetic diversity and population structure of this species and related bromeliads. Methods and Results Based on the transcriptome data of V. carinata, 30 primer pairs were designed and selected for initial validation. Of these primer pairs, 16 generated suitable SSR loci in 69 individuals. The number of alleles per locus ranged from one to 13; the levels of observed and expected heterozygosity per locus ranged from 0.000 to 1.000 and from 0.000 to 0.935, respectively. All loci produced heterologous amplification. Transferability of the loci was tested in 15 species belonging to three Bromeliaceae subfamilies. Conclusions The developed EST-SSR markers revealed polymorphism in the four studied populations and could be useful to investigate the genetic diversity of V. carinata and related species. The markers may also be suitable for novel gene annotation and discovery.

This study aims to give an overall view of fruit structure in Bromeliaceae, since these studies are extremely scarce in this family, showing the morphology, anatomy and ontogeny of fruits of six species belonging to six different genera, representing three subfamilies. All species studied have a tricarpellary and trilocular ovary, with an obturator covering the placental region. Dyckia maritima, Pitcairnia flammea, Tillandsia aeranthos and Vriesea carinata have capsular fruits (septicidal or biscidal), characterized mainly by the presence of macrosclereids in the exocarp or endocarp, fibers in the ventral region of the carpels, six dehiscence lines and three vascular bundles in each carpel. Aechmea calyculata and Billbergia nutans have fruits classified as berries, presenting exocarp and hypodermis as mechanical layers and many vascular bundles in each carpel. Many useful characters for taxonomy of Bromeliaceae were revealed, so fruits are excellent tools for delimitation of genera and subfamilies. In relation to Bromeliaceae capsules, macrosclereids are conspicuous structures of the pericarp and fruit anatomy is greatly related to dehiscence type. The U-shaped cell wall thickenings are a very common character in this family and can be identified as structures also occurring in monocot fruits.

Resuspended soil and other airborne particles adhered to the leaf surface affect the chemical composition of the plant. A well-defined cleaning procedure is necessary to avoid this problem, providing a correct assessment of the inherent chemical composition of bromeliads. To evaluate the influence of a washing procedure, INAA was applied for determining chemical elements in the leaves of bromeliads from Vriesea carinata species, both non-washed and washed with Alconox, EDTA and bi-distilled water. Br, Ce, Hg, La, Sc, Se, Sm and Th showed higher mass fractions in non-washed leaves. The washing procedure removed the exogenous material without leaching chemical elements from inside the tissues.

Epiphytic bromeliads have been used as biomonitors of air pollution since they have specialized structures in leaves for absorbing humidity and nutrients available in the atmosphere. Leaves of five bromeliad species were collected in the conservation unit Parque Estadual Ilha do Cardoso, Sao Paulo State, Brazil, and analyzed by INAA. Vriesea carinata was the species showing most accumulation, with the highest mass fractions of K, Na, Rb and Zn. Similar results were previously found for the same species collected in the dense ombrophilous forest. Chemical composition of bromeliads provided an indication of the atmosphere status in the conservation unit.

A família Bromeliaceae é uma das famílias de plantas com flores mais diversas morfologica e ecologicamente nativas do Novo Mundo, e é bem conhecida por ter sofrido radiação adaptativa recente, evoluindo para habitar inúmeros nichos e ocupando os mais diversos tipos de ambientes. Bromeliaceae surgiu no Escudo das Guianas cerca de 100 milhões de anos atrás (Ma), e linhagens modernas começaram a divergir cerca de 19 Ma, chegando na América tropical e subtropical há 15,4 Ma, aproximadamente. Devido a sua história evolutiva recente, limites genéricos frequentemente sofrem alterações na família Bromeliaceae, com espécies incipientes não completamente definidas. A Floresta Atlântica Brasileira (BAF) é um dos centros de diversidade das bromélias, sendo também um dos centros de diversidade do gênero Vriesea. Vriesea carinata e V. incurvata podem ser consideradas modelos interessantes para o estudo dos padrões históricos da BAF e também para o estudo dos processos de coesão de espécies e barreiras reprodutivas, por serem espécies endêmicas da BAF, com ampla distribuição ao longo dessa ecorregião, sendo encontradas em simpatria e compartilham polinizadores. Assim, este trabalho foi dividido em três manuscritos, buscando uma melhor compreensão da história evolutiva da família Bromeliaceae, bem como da Floresta Atlântica Brasileira. No Capítulo II, é apresentado um artigo de revisão, compilando os estudos sobre a família Bromeliaceae, no qual foram abordados aspectos como: diversidade genética, adaptações evolutivas, sistemas de cruzamento e suas consequências sobre a estruturação populacional e conservação in situ. Os dados do artigo de revisão demonstraram que Bromeliaceae tem três centros de diversidade, 58 gêneros e cerca de 3.170 espécies. As bromélias são preferencialmente polinizadas por vertebrados e apresentam uma marcante variação nos sistemas de cruzamento, de endogamia predominante à polinização cruzada obrigatória, e uma constância no número de cromossomos (x = 25). Bromélias com sistema de cruzamento autógamo ou misto têm um alto coeficiente de endogamia (FIS), enquanto que as espécies de fecundação cruzada apresentam FIS baixos. O grau de diferenciação entre as populações (FST) variou de 0,043 a 0,961, e pode ser influenciado pela dispersão do pólen e sementes, crescimento clonal, taxas de fluxo gênico e conectividade entre as populações. Bromeliaceae apresenta algumas adaptações morfológicas e fisiológicas, incluindo o metabolismo ácido das crassuláceas de fotossintese (CAM), formação de rosetas que acumulam água, tricomas absortivos nas folhas e hábito epífito, que podem ter sido cruciais para a radiação adaptativa desta família. Além disso, muitas espécies são endêmicas com distribuição restrita e/ou são encontradas em ecorregiões ameaçadas de extinção, como a BAF. A preservação deste tipo de ecorregião é vital para a conservação da família Bromeliaceae e das espécies associadas. No Capítulo III, nós estudamos os padrões filogeográficos de Vriesea carinata e V. incurvata com o objetivo de fornecer informações sobre os processos históricos que influenciaram na diversificação da BAF. Nós testamos a hipótese de que V. carinata e V. incurvata apresentariam o mesmo padrão filogeográfico, uma vez que podem ter sido submetidas às mesmas alterações climáticas no passado, pois apresentam distribuição geográfica semelhante. Foram amostradas 16 populações de V. carinata e 11 de V. incurvata, as quais utilizamos para descrever os padrões de variações genéticas do DNA plastidial (cpDNA) e nuclear (microssatélites). Vriesea carinata e V. incurvata apresentaram padrões filogeográficos semelhantes, com uma forte descontinuidade genética norte/sul entre as populações, sem compartilhamento haplotípico entre essas regiões. A presença de dois grupos genéticos distintos suporta a hipótese de que V. carinata e V. incurvata sobreviveram em mais de um refúgio durante as oscilações climáticas do Pleistoceno. Um putativo refúgio seria na porção litoranea sul-sudeste (latitude 25°S - PR/SP) e outro no sudeste do Brasil (latitude 20°S - RJ/ES). Os resultados são consistentes com registros encontrados na literatura para a BAF. No entanto, mais estudos são necessários para entender a complexa história da BAF, uma vez que este padrão foi provavelmente moldado ao longo do Pleistoceno, mas eventos anteriores, como soerguimento da costa leste brasileira durante o Terciário, também podem ter influenciado a distribuição e a diversificação dos taxa. No Capítulo IV, nós investigamos a ocorrência de hibridação natural entre V. carinata e V. incurvata em quatro populações onde elas são encontradas em simpatria. Estas espécies são bem delimitadas taxonomicamente, apresentam morfologia floral similar e compartilham polinizador (beija-flor), apresentando floração sequencial com um curto período de sobreposição do florescimento. O grau de isolamento reprodutivo entre espécies relacionadas é um fator importante que influência a integridade genética das espécies e a formação de híbridos. Foram amostradas e analisadas quatro populações simpátricas, utilizando duas regiões plastidiais e 14 locos de microssatélites, e híbridos foram encontrados em todas elas, com um total de 19 indivíduos, indicando que ocorre fluxo gênico interespecífico entre V. carinata e V. incurvata. Análises Bayesianas identificaram híbridos F2 e retrocruzamentos com V. incurvata e a rede de haplótipos do cpDNA identificou introgressão bidirecional entre estas duas espécies. Nas populações simpátricas com distribuição mais ao norte foi encontrado um maior número de híbridos, provavelmente por causa de um gradiente latitudinal, que pode influenciar nas estações do ano, temperatura, precipitação e também o período de floração das espécies. A taxa de fluxo gênico interespecífico (Nem ˂ 0,5) foi considerada alta, contribuindo para a formação de 10% de híbridos nas populações estudadas, porém a ausência de híbridos F1 indica que a barreira reprodutiva está sendo eficaz. A diferença temporal de floração das duas espécies tem atuado como uma barreira reprodutiva prezigótica forte, sendo a principal força responsável pela coesão das espécies. O conhecimento da hibridação e dos padrões de fluxo gênico interespecífico é importante para a compreensão dos processos de especiação, do movimento de genes entre espécies relacionadas e da manutenção da coesão das espécies. Em suma, os resultados obtidos no presente estudo, utilizando V. carinata e V. incurvata como modelos, permitiram aumentar a compreensão dos padrões históricos da BAF, dos processos biológicos e ecológicos envolvidos na evolução do isolamento reprodutivo responsável pela manutenção da coesão das espécies de plantas. Bromeliaceae family is one of the morphologically and ecologically most diverse flowering plant families native to the New World and is well known for its recent adaptive radiation, evolving to live in numerous niches and occupying the most diverse types of environments. Bromeliaceae arose in the Guayana Shield roughly 100 million years ago (Ma), and modern lineages began to diverge from each other roughly 19 Ma, arriving in tropical and subtropical America from near 15.4 Ma. Due to its recent evolutionary history, generic boundaries often suffer changes in the Bromeliaceae family, with incipient species not completely defined. Brazilian Atlantic Forest (BAF) is one of the centers of bromeliads diversity, being also one of the diversity centers of Vriesea genus. Vriesea carinata and V. incurvata may be interesting models for the study of BAF historical patterns and also for studying species cohesion processes and reproductive barriers, to be endemic species of BAF, with wide distribution throughout this ecoregion, being found in sympatry and share pollinators. Thus, this thesis was divided in three manuscripts, which seeking a better understanding of the evolutionary history of the Bromeliaceae family, as well as BAF ecoregion. In the Chapter II, a review manuscript were presented, compiling the studies on Bromeliaceae family using approaches as: genetic diversity, evolutionary adaptations, mating systems and their consequences on the population structure and in situ conservation. The review’s results revealed that Bromeliaceae has three diversity centers, 58 genera, and about 3,170 species. Bromeliads are preferentially pollinated by vertebrates and show marked variation in breeding systems, from predominant inbreeding to obligatory outcrossing, as well as constancy in chromosome number (x = 25). Autogamous or mixed mating system bromeliads have a high inbreeding coefficient (FIS), while outcrossing species show low FIS. The degree of differentiation among populations (FST) of species ranges from 0.043 to 0.961, and can be influenced by pollen and seed dispersal effects, clonal growth, gene flow rates, and connectivity among populations. Bromeliaceae showed some morphological and physiological adaptations, including crassulacean acid metabolism (CAM) photosynthesis, formation of rosettes that accumulate water, leaf absorptive scales and epiphytic habit, which might have been crucial to the adaptive radiation of this family. Also, many species are endemic with restricted distribution and/or are found in endangered ecoregion, as BAF. The preservation of this type of ecoregion is vital for the conservation of Bromeliaceae and associated species. In the Chapter III, we studied the phylogeographic patterns of Vriesea carinata and V. incurvata aiming to provide insights into the historical processes that underlined diversification in BAF. We evaluated the hypothesis that V. carinata and V. incurvata would present the same phylogeographic pattern, since they could be subjected to the same climatic changes in the past because they present similar geographic distribution. We sampled 16 populations of V. carinata and 11 of V. incurvata, which we use to describe the patterns of genetic variation in plastid (cpDNA) and nuclear DNA (microsatellites). Vriesea carinata and V. incurvata showed similar phylogeographic patterns, with strong genetic discontinuity among north/south populations and without haplotypic sharing among these regions. The presence of two genetic distinct groups would seem to support the hypothesis that V. carinata and V. incurvata survived in more than one fragmented refugia during Pleistocene climatic oscillations. One putative refugium was on coastal south-southeastern (latitude 25°S - PR/SP) and another in southeastern Brazil (latitude 20°S - RJ/ES). The results are consistent with records encountered in the literature for the BAF. However, more studies are required for understanding the BAF complex history, since this pattern was probably shaped throughout the Pleistocene, but earlier events, as uplift of Brazilian east coast during Tertiary, may be also influenced the distribution and diversification of taxa. In the Chapter IV, we investigated natural hybridization between V. carinata and V. incurvata in four populations where they are found in sympatry. These species are well defined taxonomically, show similar floral morphology and share pollinator (hummingbird), presenting sequential flowering and short time of blooming overlap. The degree of reproductive isolation among related species is an important factor influencing species genetic integrity and hybrids formation. We sampled and analyzed four sympatric populations, using two plastid regions and 14 microsatellite loci, and hybrids were found in all of them, with a total of 19 individuals, indicating that interspecif gene flow occurs between V. carinata and V. incurvata. Bayesian assignment analysis identified F2 hybrids and backcrosses towards V. incurvata and cpDNA haplotypic network identified bidirectional introgression between these two species. In sympatric populations with lower latitude we found a greater number of hybrids, probably because of a latitudinal gradient, which may influence the seasons of the year, temperature, precipitation, and also in flowering period of the species. The rate of interspecific gene flow (Nem ˂ 0.5) was considered high, contributing to the formation of 10% hybrids in the studied populations, however the absence of F1 hybrids indicates the reproductive barrier being effective. The temporal difference in the flowering period of the two species has acted as a strong prezygotic reproductive barrier, being the main force responsible for species cohesion. The knowledge of hybridization and patterns of interspecific gene flow are important for understanding the process of speciation, the movement of genes across species boundaries and the maintaining of species cohesion. Finally, the results obtained in this study, using V. carinata and V. incurvata as a models, allow us to increase the understanding of BAF historical patterns, and of biological and ecological processes involved in the development of reproductive isolation responsible for maintaining the cohesion of plant.