In this study three aspects of sexual reproduction in Everglades plants were examined to more clearly understand seed dispersal and the allocation of resources to sexual reproduction— spatial dispersal process, temporal dispersal of seeds (seedbank), and germination patterns in the dominant species, sawgrass (Cladium jamaicense). Community assembly rules for fruit dispersal were deduced by analysis of functional traits associated with this process. Seedbank ecology was investigated by monitoring emergence of germinants from sawgrass soil samples held under varying water depths to determine the fate of dispersed seeds. Fine-scale study of sawgrass fruits yielded information on contributions to variation in sexually produced propagules in this species, which primarily reproduces vegetatively. It was hypothesized that Everglades plants possess a set of functional traits that enhance diaspore dispersal. To test this, 14 traits were evaluated among 51 species by factor analysis. The factorial plot of this analysis generated groups of related traits, with four suites of traits forming dispersal syndromes. Hydrochory traits were categorized by buoyancy and appendages enhancing buoyancy. Anemochory traits were categorized by diaspore size and appendages enhancing air movement. Epizoochory traits were categorized by diaspore size, buoyancy, and appendages allowing for attachment. Endozoochory traits were categorized by diaspore size, buoyancy, and appendages aiding diaspore presentation. These patterns/trends of functional trait organization also represent dispersal community assembly rules. Seeds dispersed by hydrochory were hypothesized to be caught most often in the edge of the north side of sawgrass patches. Patterns of germination and dispersal mode of all hydrochorous macrophytes with propagules in the seedbank were elucidated by germination analysis from 90 soil samples collected from 10 sawgrass patches. Mean site seed density was 486 seeds/m2 from 13 species. Most seeds collected at the north side of patches and significantly in the outer one meter of the patch edge (p = 0.013). Sawgrass seed germination was hypothesized to vary by site, among individual plants, and within different locations of a plant’s infructescence. An analysis of sawgrass fruits with nested ANOVAs found that collection site and interaction of site x individual plant significantly affect germination ability, seed viability, and fruit size (p < 0.050). Fruit location within a plant’s infructescence did not significantly affect germination. As for allocation of resources to sexual reproduction, only 17.9% of sawgrass seeds germinated and only 4.8% of ungerminated seeds with fleshy endosperm were presumed viable, but dormant. Collectively, only 22% of all sawgrass seeds produced were viable.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The knowledge of the trophic interactions of fruit bats is fundamental to understand the role of these animals in the organization of tropical ecosystems. The present study, the fauna of fruit bats and food items that composed the diet of the species in the “Resting” of Northeast Brazil were determined. Similarity in the diet of the bats and the influence of seasonality and sex on the consumption of the resources were avaluated. Subsequently, the species of plants and seeds that passed through the digestive tract of the bats were identified for the evaluation of the germinative behavior (percentage, mean germination time, germination speed and synchronization index) of the seeds of four pioneer plant species (Cecropia pachystachya, Passiflora silvestris, Solanum asperum and Vismia guianensis). Seeds consumed by bats Artibeus lituratus and Carollia perspicillata were compared to unconsumed seeds (collected from fruits). Between October 2016 and September 2017, eight species of fruit bats were captured and nine species of plants identified in their fecal samples. The association between species based on diet content showed that these can be divided into three groups: specialists in Cecropia (A. lituratus and A. planirostris), specialist in Solanum (D. cinerea) and generalist (C. perspicillata). Carollia perspicillata contributed with seed samples throughout the year, having its diet influenced by seasonality. However, differences in the diet of males and females of this species were not observed. It was observed that the germination of C. pachystachya was significantly benefited after ingestion by A. lituratus. Seeds of S. asperum, P. silvestris and V. guianensis consumed by C. perspicillata presented neutral and negative effects on germinability in relation to seeds collected from fruits. The results of the present study indicated that the species seem to adapt to the different conditions of food supply during the dry and rainy periods, modifying their diet or moving to other areas where they can consume fruits of their preference. In addition, the same species of bat can produce distinct effects on the germinative behavior of seeds consumed, as well as different bats can contribute in a differentiated way in the establishment rates of plants in the restinga, mainly in the initial stages of succession. / Conhecer as interações tróficas dos morcegos frugívoros é fundamental para se entender o papel desses animais na organização dos ecossistemas. No presente estudo, a fauna de morcegos frugívoros e os itens alimentares que compunham a dieta das espécies na restinga do Nordeste do Brasil foram determinados. Também foi avaliada a similaridade na dieta dos quirópteros e a influência da sazonalidade e do sexo no consumo dos recursos. Subsequentemente, as espécies de plantas e sementes que passaram pelo trato digestório dos morcegos foram identificadas para a avaliação do comportamento germinativo (porcentagem, tempo médio de germinação, velocidade de germinação e índice de sincronização) das sementes de quatro espécies de plantas pioneiras (Cecropia pachystachya, Passiflora silvestris, Solanum asperum e Vismia guianensis). Sementes consumidas pelos morcegos Artibeus lituratus e Carollia perspicillata foram comparadas com sementes não consumidas (coletadas dos frutos). Entre outubro de 2016 e setembro de 2017, oito espécies de morcegos frugívoros foram capturadas e nove espécies de plantas identificadas em suas amostras fecais. A associação entre espécies com base no conteúdo da dieta mostrou que estas podem ser divididas em três grupos: especialistas em Cecropia (A. lituratus e A. planirostris), especialista em Solanum (D. cinerea) e generalista (C. perspicillata). Carollia perspicillata contribuiu com amostras de sementes durante todo o ano, tendo sua dieta influenciada pela sazonalidade. Entretanto, diferenças na dieta de machos e fêmeas dessa espécie não foram constatadas. Foi observada que a germinação de C. pachystachya foi significativamente beneficiada após a ingestão por A. lituratus. Sementes de S. asperum, P. silvestris e V. guianensis consumidas por C. perspicillata apresentaram efeitos neutros e negativos na germinabilidade em relação às sementes coletadas dos frutos. Os resultados do presente estudo indicaram que as espécies parecem adequar-se às diferentes condições de oferta de alimentos durante os períodos seco e chuvoso, modificando sua dieta ou deslocando-se para outras áreas onde possam consumir frutos de sua preferência. Além disso, uma mesma espécie de morcego pode produzir efeitos distintos no comportamento germinativo das sementes consumidas, assim como morcegos diferentes podem contribuir de forma diferenciada nas taxas de estabelecimento de plantas na restinga, principalmente nos estádios iniciais de sucessão. / São Cristóvão, SE

Factors determining distribution of species in semi-natural grasslands Survival and colonization of plant species in fragmented landscapes are topic of many recent studies. Most of them deal with one or just a few species or with overall species diversity. There are also a lot of studies devoted to the effect of abiotic characteristics and other parameters of fragmented habitat patches. Studies that would enable to evaluate behaviour of a large number of individual species are still relatively rare, especially in case of grassland species. Comparison of species traits in conjunction with the knowledge of type of historical land use and abiotic requirements of species can be a key to understanding of current species dispersal and their regional dynamic in fragmented landscape. This method of prediction of species dispersal can be a good implement for landscape planning and conservation of species and also their habitats. Goal of my thesis was to determine which traits of species influence response of species on land-use history in fragmented habitat of dry grasslands. I tried to use effect of land-use history without effect of environmental factors on species composition in phytosociological relevés. Then I tried to explain the reaction of species through their traits. I focused partially on traits...

Die Samenausbreitung ist eine entscheidende Phase im Lebenszyklus von Pflanzen. Verschiedene Mechanismen haben sich entwickelt, um eine erfolgreiche Keimung zukünftiger Generationen sicherzustellen. Diese schließen die Selbstverbreitung von Samen durch hygroskopische Bewegung von Grannen neben der Verbreitung durch Wind, Wasser oder Tiere ein. Das Verständnis der Struktur-Funktions-Beziehung ist sowohl für das Verstehen, wie sich Pflanzen an spezifische Umweltbedingungen anpassen können, als auch für die potenzielle Entwicklung biomimetischer Anwendungen wichtig. Diese Dissertation konzentriert sich auf die Ausbreitung von Taubem Hafer (Avena sterilis) und zielt darauf ab, die komplexe Bewegung der Grannen zu charakterisieren. Dies wird erreicht, indem die Zellwandstruktur und -zusammensetzung, welche die Bewegung antreiben, mit einer Reihe von komplementären mikroskopischen und spektroskopischen Methoden analysiert werden. / Seed dispersal is a crucial stage in the life cycle of plants. Different mechanisms have evolved to ensure successful germination of future generations. This includes the self-dispersal of seeds by hygroscopic movement of awns among dispersal by wind, water, or animals. Understanding the structure-function relationship is important to comprehend how plants can adapt to specific environmental conditions and also for potential development of biomimetic applications. This thesis focuses on the dispersal of wild oats (Avena sterilis) and aims to characterize the complex movement of the awns by analyzing the cell wall structure and composition that drives the motion with a range of complementary microscopic and spectroscopic methods.

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Dispersal is a key trait across biology. Within plants, a variety of explosive seed dispersal mechanisms are seen. Whilst ecological and mechanical studies have described this important evolutionary adaptation in many species, a genetic and developmental understanding of explosive seed dispersal is lacking. In this thesis, the morphology and development of the explosive seed pods of Cardamine hirsuta – a member of the Brassicaceae – are characterised in detail, with reference to its close relative, the model organism A. thaliana. Comparison of fruit morphology between these two species and across other Brassicacean species generated hypotheses regarding the function and polarity of morphological features. In order to identify genes that are necessary for C. hirsuta fruit development, a genetic screen was conducted and a range of mutants identified and subsequently characterised. Analysis of the indehiscent valveless (val) mutant revealed a loss of valve tissue and an expansion of valve margin identity in the silique. Mapping and sequencing identified a mutation in the MADS-box gene FRUITFULL (FUL), which results in a truncated protein, as the likely cause of the val phenotype. Consideration of ful mutants in C. hirsuta and A. thaliana allowed comparison of the genetic patterning of the fruit dehiscence zone in these two species. The genetic interactions between fruit mutants characterised in this thesis and mutants in shoot patterning genes revealed common regulatory networks underlying leaf and fruit development in C. hirsuta. Together, comparison of wild-type and mutant C. hirsuta siliques with those of A. thaliana and other Brassicacean species suggests that specialised cell layers within the valve silique region are of key importance to C. hirsuta’s explosive dehiscence mechanism.

For a long time studies were focused on searching optimal conditions of germination of individual species. During the last few years studies have started to search for a relationship between germination and various species characteristics. Most of them, however, use only one temperature during germination tests. Very few studies use more than one temperature during the germination tests. In the last years studies started also to compare germination between rare and common species, but these studies compare just a few species. There are no studies which would compare germination on broader range of species. Aim of this study was to indentify which factors are determing germination of species and to find relationships between germination and characteristics of rare species (n=62). Another aim was to find out differences in germination of pairs (n=24) of closely related rare and common species. To test the germination I have chosen a methodology with several consecutive temperatures. Throughout the time of testing , the seeds were placed either in light or in dark. The dataset was processed by linear regression. The results show that germination requirements of species are determinet by time of flowering, weight of seeds, dispersal mode, species requirements for soil humidity and nutrients and type of...