From the 1840s to 1950s, interpretations of nature played a central role in the defining and enculturating the Sonoran Desert into the American nation. Written works and physical nature like plants became an archive for cultural interpretations of the region. Scientific descriptions of nature became stories of place as they were consumed. Proxy landscapes like national monuments became the spaces for demonstrating these stories. Throughout the period of this study, a constant give and take between regional nature and global arid lands shaped the national interpretations used to describe regional nature within the American nation-state. This work follows the production and consumption of meaning and the definition of a desert region.

Rapporten tar upp en kartläggning av nätverksövervakningssystem (NMS) som används för att övervaka nätverkstjänster och noder på ett nätverk. De egenskaper för NMS som utvärderas är vilket stöd systemen har för att övervaka ett flertal tjänster, hur god prestandan är för varje system samt hur god användbarheten i gränssnittet är. Resultatet visar att Nagios, OpenNMS samt Argus hade stöd för samtliga tjänster medan Munin inte hade stöd för nätverksenheter och Cacti endast stöd att övervaka SNMP. Det visar även att Nagios och OpenNMS generellt hade möjlighet att larma vid fler händelser samt att dessa två system var markant snabbare än Cacti och Munin. Användbarheten visade relativt stor skillnad i olika system. OpenNMS hade högst totalpoäng, men Nagios presterade något bättre i vad Sundström (2005) kallar för interaktion. Munin och Argus fick samma resultat med låg funktionalitet och högre struktur medan Cacti hade god funktionalitet och interaktion men väldigt låg struktur.

<p>Rapporten tar upp en kartläggning av nätverksövervakningssystem (NMS) som används för att övervaka nätverkstjänster och noder på ett nätverk. De egenskaper för NMS som utvärderas är vilket stöd systemen har för att övervaka ett flertal tjänster, hur god prestandan är för varje system samt hur god användbarheten i gränssnittet är. Resultatet visar att Nagios, OpenNMS samt Argus hade stöd för samtliga tjänster medan Munin inte hade stöd för nätverksenheter och Cacti endast stöd att övervaka SNMP. Det visar även att Nagios och OpenNMS generellt hade möjlighet att larma vid fler händelser samt att dessa två system var markant snabbare än Cacti och Munin. Användbarheten visade relativt stor skillnad i olika system. OpenNMS hade högst totalpoäng, men Nagios presterade något bättre i vad Sundström (2005) kallar för interaktion. Munin och Argus fick samma resultat med låg funktionalitet och högre struktur medan Cacti hade god funktionalitet och interaktion men väldigt låg struktur.</p>

The microorganisms that live in and on a host (the microbiome) influence host phenotype, health, and behavior in plants and animals. However, the effects of the host and environment on the composition of microbiome communities are unclear. This is especially true in arid and semi-arid environments such as deserts that filter many microorganisms. This study investigated variation in phyllosphere microbiotal bacterial assemblages of prickly pear cactus (Opuntia) across differing spatial scales, ecoregions, and taxa throughout Texas at two timepoints. I expected bacterial assemblages to differ significantly among Texas ecoregions and among species. Results support significant influences on bacterial assemblage composition including ecoregion, taxonomy, and potentially seasonal time of sampling. The dry season timepoint yielded high microbial diversity and abundance across species and ecoregions, with different species and ecoregions harboring unique microbial communities. The rainy season timepoint yielded significantly lower levels of microbial diversity and abundance across species and ecoregions.

"Why have separate sexes?" is a fundamental question in biology and has been investigated intensively since Darwin first proposed two hypotheses: Separate sexes evolve 1) to avoid detrimental effects of self-fertilization or 2) to improve allocation of scarce resources to each sex's reproductive function. In animal-pollinated plants dioecy is hypothesized to be favored when small, generalized pollinators predominate because they increase self-fertilization rates of plants. I concurrently tested Darwin's hypotheses using Echinocereus coccineus (Cactaceae). I found, as predicted, when specialized pollinators (hummingbirds) were excluded from plants and only generalized pollinators (bees) visited, selfing rates of plants increased 238%. High selfing rates produced by bees, along with high levels of inbreeding depression in E. coccineus populations, were sufficient to select for dioecy, even in absence of any reallocation of resources by the plants. Hummingbirds may also maintain high levels of gene flow among E. coccineus populations: populations blooming synchronously with the hummingbird migration had lower FST values (i.e. less genetic divergence) than asynchronously blooming populations. Population genetic data also suggest frequency of dioecious populations should be negatively correlated with both hummingbird abundance and elevation. Structural equation models of effects of hummingbird abundance, elevation and annual rainfall (resources) on dioecy across the range of E. coccineus supported this hypothesis. All predictor variables were either directly or indirectly negatively correlated with dioecy. Only models with hummingbird abundance as a direct predictor of dioecy significantly fit the data. Darwin's first hypothesis was again supported: as hummingbird abundance declines (and selfing rates increase), the incidence of dioecious populations increases. Finally, to determine how changes in pollinator type may be globally influencing the evolution of dioecy, I conducted a literature survey of studies noting changes in pollinator types along elevation gradients and compared these to studies of dioecy along elevation gradients. The abundance of specialized insect pollinators declines with elevation, often leaving only generalized pollinators at the highest elevations: Proportion of dioecious species in communities increases accordingly with elevation. I propose elevation may be useful as a worldwide predictor of dioecy because it effects pollinator community composition and amount of inbreeding depression expressed in plant populations.

Innovative restoration strategies are critically needed in the South Texas Plains for controlling increased Opuntia cacti invasions. Using a replicated and randomized experimental study, I have examined the effects of fire seasonality and herbivory on the dominant cacti and herbaceous plant species in this semi-arid ecosystem. Results from this study demonstrate that the combination of fire and wildlife herbivory significantly reduces Opuntia cactus cover. I was able to empirically demonstrate that prescribed fire decreases prickly pear cactus cover. Moreover, this decrease is further exacerbated by the effects of large mammalian herbivores consuming and/or disturbing recently burned mottes. In the absence of fire, both mottes with and without herbivore exclosures increased in size. The ecological insights gained from this study will contribute to the development of management strategies of Opuntia cacti, while promoting the restoration and long-term sustainability of Texas rangelands.

Os estudos com traqueídes vasculares em Caryophyllales têm focalizado questões filogenéticas e funcionais. Embora sejam descritas como traqueídes, com espessamento da parede secundária superior a 2µm, o relato de WBTs em diferentes tecidos em outras famílias evidencia que a definição dessas células não está bem estabelecida. O objetivo deste trabalho é compreender a ontogenia das traqueídes vasculares de Pilosocereus aurisetus (cacto colunar), descrevendo a sua estrutura em nível celular e bioquímico, bem como suas implicações funcionais e evolutivas. Para isso foi descrita a ontogênese, como base para o estudo de composição de parede, e anticorpos foram utilizados para melhor entendimento das moléculas de relevância funcional. Além disso, uma revisão anatômica que sintetiza o conhecimento atual sobre ocorrência das WBT, polimorfismo do lenho e diversidade de hábitos foi inserida em um contexto filogenético, a fim de esclarecer o papel do polimorfismo do lenho na evolução de Cactoideae. Plântulas foram incluídas em parafina para obtenção de cortes seriados, analisados em microscopia óptica e confocal. A análise de composição de parede celular foi feita com tecido xilemático de plântulas, cujos polissacarídeos foram sujeitos a hidrólise ácida, seguida de análise em cromatografia. Na imunolocalização foram utilizados os anticorpos anti-galactano LM5 e anti-arabinano LM6, para pectinas, e anti-manano, para hemiceluloses. Dados sobre a presença de traqueídes vasculares e do tipo de lenho em Cactaceae foram coletados da literatura e mapeados em uma filogenia robusta. A grande proporção de parede primária, associada à deposição de galactano, permite a função de armazenamento de água. Além disso, o aumento de parede secundária associada à deposição de manano na base, sugere função de sustentação nesta região, ainda que, somente a formação do lenho fibroso pareça fornecer o suporte necessário para que um cacto colunar atinja a altura de um adulto. Tal processo parece ter sido a predisposição anatômica crucial para a evolução dos cactos colunares. O presente estudo fornece um panorama amplo e novas evidências sobre a origem e função das traqueídes vasculares de Cactaceae. / Studies with wide-band tracheids have adressed phylogenetic and functional questions. Although these cells have been described as tracheids, with secondary cell walls thicker than 2µm, their recent register in different tissues of other families has pointed out that this definition may not be well established. The aim of the present study is to understand the ontogeny of the wide-band tracheids in Pilosocereus aurisetus (a columnar cactus), describing their structure at both celular and biochemical levels, and to investigate their possible functional and evolutionary implications for the Cactoideae as a whole. Therefore, Pilosocereus aurisetus ontogeny was studied as basis to cell wall composition analyses. Such analyses involved the use of antibodies and the identification of molecules of functional relevance. Furthermore, an anatomical review that summarizes the current knowledge about wide-band tracheid occurrence, wood polymorphism, and habit diversity was analyzed within a phylogenetic framework to investigate the role of polymorphic wood in Cactoideae evolution. Seedlings were embedded in paraffin, and the resulting sections were analyzed in optical and confocal microscopy. Studying the cell wall composition in seedling xylem involved the use of acid hydrolization of polysaccharides followed by chromatography analysis. The antibodies used for imunocitolocalization were anti-galactan LM5 and anti-arabinan LM6, for pectins, and anti-mannan, for hemicelluloses. Data about wide-band tracheids occurrence and wood polymorphism in Cactaceae were collected from the literature and mapped in a robust phylogeny for the subfamily. The prevalent proportion of primary cell wall with galactan suggests a water storage function for the wide-band tracheids. Furthermore, the rise of secondary cell wall deposition, and the high concentration of mannan in the cactus base suggest a sustaining function for this region. However, the fibrous wood development alone seems to provide enough support to sustain a mature columnar cactus. Such process may have been the most important anatomical prerequisite in the evolution of columnar cacti. The present study offers an overview and new evidences for the origin and function of wide-band tracheids.

Made available in DSpace on 2016-04-28T14:58:35Z (GMT). No. of bitstreams: 1 2008 - Thais Moreira Hidalgo de Almeida.pdf: 3286442 bytes, checksum: 491a402cc8bf5539730d0625fcbf7b31 (MD5) Previous issue date: 2008-02-28 / Germination, conservation and physical characteristics of seeds of four cacti species that occurs on Rio de Janeiro State coastal regions, Cereus fernambucensis Lem., Coleocephalocereus fluminensis (Miq.) Backeb., Pilosocereus arrabidae (Lem.) Byles & G.D. Rowley and Pilosocereus ulei (K. Schum.) Byles & G.D. Rowley were evaluated in this study. The first experiment, mounted in a completely randomized design and factorial system, tested two substrates (agar 1% and paper) and three temperatures (20?C, 25?C and 20-30?C) using four replicates of 40 seeds. The evaluation parameters were germination percentage (normal seedlings) and germination average time (ANOVA and Tukey; P<0,05). According to the germination analysis, the best combination of temperature and substrate is 20?C in agar for C. fernambucensis, 20?C and 20-30?C in paper or agar for C. fluminensis, 25?C in agar for P. arrabidae and 20, 25 and 20-30?C in paper, as well as, 20 and 25?C in agar for P. ulei. The use of agar 1% was suitable for germination of this cacti seeds, being necessary, however, studies that lead to reduction in the incidence of plant health problems. In another experiment the effects of storage and seed water content were evaluated on the germination percentage and germination average time of these four species. To better define the salts to be used in the seed drying process for this experiment, adsorption isotherms were built using static gravimetric method, with saturated salt solutions. The isotherms of all species showed a reverse sigmoidal pattern with increase of seed water content according to the increase in relative humidity. In the conservation experiment, also arranged in completely randomized design and factorial system, three different storage conditions (control, 30 days at 10?C and 30 days at -196?C) under three levels of water content, around 5, 7 and 9% (dry basis) were tested, with four replicates of forty seeds (ANOVA and Tukey; P<0,05) at the following conditions: C. fernambucensis in agar at 20?C, C. fluminensis and P. ulei in paper at 20?C and P. arrabidae in agar at 25?C. All four species showed dehydration and sub-zero temperature tolerance. Seed viability and four species showed dehydration and sub-zero temperature tolerance. Seed viability and vigour showed no changes when stored with water content around 7%, at 10?C and cryopreserved at -196?C. Cryopreservation can be recommended for the storage of this cacti species. / As caracter?sticas f?sicas, germina??o e conserva??o de sementes de quatro esp?cies de cact?ceas ocorrentes nas ?reas litor?neas do estado do Rio de Janeiro, Cereus fernambucensis Lem., Coleocephalocereus fluminensis (Miq.) Backeb., Pilosocereus arrabidae (Lem.) Byles & G.D. Rowley e Pilosocereus ulei (K. Schum.) Byles & G.D. Rowley foram avaliadas neste estudo. O primeiro experimento, montado em delineamento inteiramente casualizado e esquema fatorial, testou dois substratos (?gar 1% e sobre papel ) e tr?s temperaturas (20?C, 25?C e 20-30?C) utilizando quatro repeti??es de 40 sementes. Os par?metros de avalia??o foram porcentagem de germina??o (pl?ntulas normais) e tempo m?dio de germina??o (ANAVA e Tukey; P<0,05). De acordo com a an?lise de germina??o, as melhores temperaturas e substratos para a germina??o de sementes de C. fernambucensis s?o 20?C e ?gar; para C. fluminensis, 20?C e 20-30?C, tanto no substrato papel como em ?gar, para P. arrabidae, 25?C em ?gar e para P. ulei em papel a 20, 25 e 20-30?C e ?gar a 20 e 25?C. O uso de ?gar 1% se mostrou adequado a germina??o das sementes destas cact?ceas, sendo necess?rios, no entanto, estudos que levem a redu??o da incid?ncia de problemas fitossanit?rios. Em outro experimento foram avaliados os efeitos de armazenamento e teor de ?gua das sementes sobre o percentual e o tempo m?dio de germina??o destas quatro esp?cies. Para melhor defini??o dos sais a serem usados na secagem das sementes para este experimento, foram constru?das isotermas de adsor??o utilizando-se o m?todo gravim?trico, est?tico, com solu??es salinas saturadas. As isotermas de todas as esp?cies revelaram um padr?o sigmoidal inverso com o acr?scimo de teor de ?gua das sementes em fun??o do aumento da umidade relativa do ar. No experimento de conserva??o, tamb?m montado em delineamento inteiramente casualizado e esquema fatorial, foram testadas tr?s diferentes condi??es de armazenamento (controle, 30 dias a 10?C e 30 dias a -196?C) sob tr?s diferentes teores de ?gua, pr?ximos a 5, 7 e 9% (base seca), utilizando quatro repeti??es de 40 sementes (ANAVA e Tukey; P<0,05) e nas seguintes condi??es: C. fernambucensis em ?gar a 20?C, C. fluminensis e P. ulei em papel a 20?C e P. arrabidae em ?gar a 25?C. As quatro esp?cies demonstraram toler?ncia a desidrata??o e a temperatura sub-zero. A viabilidade e o vigor das sementes n?o apresentaram altera??es quando armazenados com teores de ?gua pr?ximos a 7%, tanto em c?mara fria a 10?C como criopreservado a -196?C. A criopreserva??o pode ser recomendada para o armazenamento das esp?cies estudadas.

The invasive cactus moth, Cactoblastis cactorum, poses a threat to opunitoid cacti species of North America. The following work contains four separate studies investigating C. cactorum host plant preference and performance, predation and parastitism of C. cactorum, effects of C. cactorum on local Opuntia populations, and associational effects of host and non-host plants on C. cactorum and native Opuntia-feeding herbivores. We found that, among southwestern and Mexican opuntioid taxa, moths preferred O. engelmannii var. linguiformis and var. engelmannii for oviposition, while Consolea rubescens and O. streptacantha were superior larval hosts. Oviposition was best predicted by number of cladodes and degree of spininess; epidermal toughness was a significant predictor of most larval fitness parameters. In general, oviposition preference was not correlated with larval performance. A lack of co-evolutionary history between C. cactorum and North American opuntioid species may help explain this disconnect. We placed irradiated C. cactorum eggsticks and pupae on Opuntia plants in the field to test for predation. We found evidence of predation, most likely from ants, on ~16% of eggsticks and ~18% of pupae. Predation rates, ant abundance, and cladode growth were higher, and C. cactorum damage lower, on Opuntia located near the extrafloral nectar-producing legume Chamaecrista fasciculata. We attribute these associational effects to the ability of C. fasciculata to attract ants to its extrafloral nectar. Over the course of six years, ~78% of nearly 600 tagged Opuntia were attacked by C. cactorum at least once and ~76% of the plants survived. Two separate studies found that Opuntia stricta was more likely to be attacked by C. cactorum than O. humifusa; we also found that O. stricta was more likely to die following an attack. A plant's odds of survival decreased as C. cactorum attack frequency increased, but plants that did survive had positive growth rates, regardless of attack status. We did not find significant evidence of associational effects for O. humifusa and O. stricta, either for C. cactorum or native Opuntia-feeding herbivores. It could be that present herbivore densities are low enough, and host plants plentiful enough, to avoid mechanisms that usually lead to associational resistance or susceptibility. Overall, our results suggest that the presence and spread of C. cactorum should be taken seriously, especially for rare opuntioids and the Opuntia-rich deserts of North America. However, for more common opuntioid host species, there may be enough resistant or tolerant individuals, and sufficient top down control through ant predation, for populations to persist at current C. cactorum densities. We acknowledge that information on Opuntia reproduction and recruitment rates are needed to confirm this suggestion, and see this as an excellent opportunity for future research

The Cactaceae family is botanically distributed in 100 genera and about 1500 species, it is subdivided into four Subfamilies that are: Maihuenoideae, Pereskeoideae, Opuntioideae and Cactoideae. This family includes the botanical group heliophila plants, dicotyledonous angiosperm, it represents the second most numerous group of Neotropical region and they are found in a great diversity of climate, soil and ecosystems, with higher occurrence of Caatinga, tropical forests, Cerrado, rock fields and Sandbanks. The cacti of the genus Melocactus (Link & Otto) are part of the subfamily Cactoideae and comprises a total of 38 species and 25 subspecies. Perennial plant with non-segmented stem has a unique feature of the group that is the presence of the terminal cephalium and the exclusive propagation by seed. Despite numerous scientific studies on cacti in Brazil, the geographical distribution, population size and conservation status of most species has been little studied, worrying fact since the totality of currently cataloged Melocactus nine are listed with endangered. Therefore, this study aimed to map and survey Melocactus species that occur in the State of Sergipe, research the ethnobotanical interactions of the Cactaceae in the state and promote seed germination with the substrates test of M. violaceus and zehntneri. The instruments used were research fields in which were determined the geographical coordinates, altitude, presence of species in the reproductive phase and fruiting. The ethnobotanical data were obtained through semi-structured research with the application of a standardized questionnaire to 36 residents. For the germination experiment experimental design was completely randomized with four replications of 25 seeds. The Relative Frequency of germination, mean germination time, speed of germination index, shoot length, length and diameter length Radicle were evaluated. Through this work was recorded the occurrence of a new species of Melocactus and as well as the occurrence of this genus in 18 counties in the state of Sergipe. In relation to the ethnobotanical survey species of cacti were identified, they were grouped into four categories of uses: medical, food and feed, construction and manufacture of objects, ornamental and mysticism. Regarding the germination experiment, M. violaceus species showed higher germination rate than the species M. zehntneri, the soaked / dehydrated and not soaked seeds showed no significant difference in germination and the substrate that showed the best results for M. and M. violaceus was zehntneri S2(50% + 50% washed sand topsoil) and S1(100% sand washed) respectively. / A família Cactaceae é botanicamente distribuída em 100 gêneros e aproximadamente 1500 espécies, está subdividida em quatro Subfamílias que são: Maihuenoideae, Pereskeoideae, Opuntioideae e Cactoideae. Essa família integra o grupo botânico de plantas heliófilas, Angiospermas dicotiledônias, representa o segundo grupo mais numeroso da região neotropical e são encontradas em uma diversidade muito grande de clima, solo e ecossistemas, com maior ocorrência da Caatinga, florestas tropicais, Cerrado, Campos rupestres e Restingas. Os cactos do gênero Melocactus (Link & Otto) fazem parte da Subfamília Cactoideae e é composto por um total de 38 espécies e 25 subespécies. Vegetal perene com caule não segmentado, apresenta uma característica única do grupo que é a presença do cefálio terminal e propagação exclusiva por sementes. Apesar dos inúmeros trabalhos científicos sobre os cactos no Brasil, a distribuição geográfica, o tamanho da população e o estado de conservação de boa parte das espécies ainda é pouco estudada, fato preocupante, pois da totalidade de Melocactus catalogado atualmente nove encontram-se listados com em risco de extinção. Neste sentido, esta pesquisa objetivou mapear e fazer um levantamento das espécies de Melocactus que ocorrem no Estado de Sergipe, pesquisar as interações etnobotânicas das cactáceas no Estado e promover a germinação de sementes com teste de substratos das espécies M. zehntneri e M. violaceus. Os instrumentos utilizados foram pesquisa de campos nas quais foram determinadas as coordenadas geográficas, altitude, presença de espécies em fase reprodutiva e presença de frutos. Os dados etnobotânicos foram adquiridos através de pesquisa semiestruturada com aplicação de questionário padronizado a 36 moradores. Para o experimento de germinação o delineamento experimental utilizado foi inteiramente casualizado com quatro repetições de 25 sementes. Foram avaliados a Frequência Relativa da Germinação, Tempo Médio de Germinação, Índice de Velocidade de Germinação, comprimento da Parte Aérea, Tamanho do Diâmetro e comprimento da Radícula. Através deste trabalho foi registrado a ocorrência de uma espécie nova de Melocactus e como também a ocorrência deste gênero em 18 municípios do Estado de Sergipe. Em relação ao levantamento etnobotânico foram identificadas nove espécies de Cactos que foram agrupados em quatro categorias de usos: medicinal; alimentação humana e animal; construção e fabricação de objetos; ornamental e misticismo. No que tange ao experimento de germinação, a espécie M. violaceus apresentou maior índice de germinação que a espécie M. zehntneri, as sementes embebidas/desidratadas e não embebidas não apresentaram diferença significativa na germinação e o substrato que apresentou os melhores resultados para os M. zehntneri e M. violaceus S2(50% areia lavada + 50% terra vegetal) e S1(100% areia lavada) respectivamente.