The historical and ecological relationships between the Tohono O'odham and the Sonoran desert landscape are expressed in the stories they tell. The Tohono O'odham have lived in the deserts of southwestern Arizona and northern Mexico for centuries, interacting with their environment and gaining intimate knowledge of desert botanical communities. Many of these interactions are dramatized in their traditional oral narratives. I have characterized those traditional oral narratives that illustrate and articulate Tohoro O'odham interrelationships with Sonoran desert botanical communities as "plant emergence narratives." These stories embody and express the reciprocal relationsihp between the Tohono O'odham and the plants they cultivate or harvest from the wild. In examining these narratives, I discuss some of the many levels on which they operate, specifically the intersection of cultural worldview with scientific data, or what I term "cultivation lore." This discussion focuses on an exploration of the stories of corn emergence to the Tohono O'odham, with comparative analysis of stories that dramatize wild plant emergence. The significance of these narratives to the Tohono O'odham and to others is discussed in the context of history, folklore, and ecology, specifically the current crisis in loss of biological diversity. By exploring the cultural value and ecological content of these plant emergence narratives, I suggest that we may discover solutions to the question of how we may live with awareness and conviction to both our human and ecological landscapes.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The sunflower cultivation has great potential for success in different edaphoclimatic regions. However, the stress occurrence, including the water excess on soil is detrimental to the crop development and production. The aim of this study was to determine the initial development stages wherein water excess and its duration affect longer negatively the emergence and early growth of sunflower plants. The experiments were carried out in the experimental area of Departamento de Fitotecnia of UFSM, during the second half of 2011. Three experiments were carried out under greenhouse and a field experiment. The experiments under greenhouse were carried out in pots, with treatments based on the application of water excess at different stages of development (at sowing date, three days after sowing, emergency date, V2 and V4 stage) combined with different durations (0, 48, 96, 144, 192 and 240 hours), in a completely randomized design, bifactorial. We determined the following variables: percentage and speed of emergency after emergency stabilization; dry mass of shoots and roots, leaf area, plant height, leaf number, maximum length of roots and main length root, and some growth index, determined after the end of application the last treatment of water excess. The field experiment was carried out in a completely randomized design, consisting of weekly sowing made between 28/07/2011 and 27/11/2011, which occurred in different conditions of excess water, soil temperature and soil moisture. Soil temperature was monitored by Pt-100 sensors, while excess water and soil moisture were determined by sequential water balance, which were correlated with the percentage of emergence, speed emergence and number of days of the phase sowing-emergency. It was found that the water excess is more detrimental for sunflower in phase sowing-emergence, because it affects negatively the emergence and consequently the plants density, reducing the growth of shoots and roots significantly, even after just 48 hours under water excess. Applied after emergence, the water excess causes significant reduction of shoot growth, while in the soil occurs development of adventitious and secondary roots. Both water excess as water deficit is detrimental to the field emergency, because soil moisture between 80 and 85% of the soil storage capacity and soil temperature of 21.5 °C are the best conditions to sunflower emergence. / O cultivo de girassol tem grande potencial de sucesso em diferentes regiões edafoclimáticas. Entretanto, a ocorrência de estresses, dentre eles o excesso hídrico do solo, é prejudicial ao desenvolvimento e produção da cultura. O objetivo deste trabalho foi determinar os estágios iniciais de desenvolvimento em que a ocorrência de excesso hídrico e sua duração mais afetam negativamente a emergência e o crescimento inicial de plantas de girassol. Os experimentos foram conduzidos na área experimental do Departamento de Fitotecnia da UFSM, durante o segundo semestre de 2011. Foram realizados três experimentos em casa de vegetação e um experimento a campo. Na casa de vegetação os experimentos foram conduzidos em vasos, com tratamentos constando da aplicação de excesso hídrico em diferentes estágios iniciais de desenvolvimento (data da semeadura, três dias após a semeadura, data da emergência, estágio V2 e estágio V4) combinados com diferentes durações (0, 48, 96, 144, 192 e 240 horas), sendo bifatorial no delineamento inteiramente casualizado. Foram determinadas as variáveis: porcentagem e velocidade de emergência após a emergência estabilizar; massa seca de parte aérea e raízes, área foliar, altura de plantas, número de folhas, comprimento máximo de raízes e da raiz principal, além de alguns índices de crescimento, determinadas ao final da aplicação do último tratamento de excesso hídrico. O experimento a campo, conduzido no delineamento inteiramente casualizado, constando de semeaduras semanais realizadas entre 28/07/2011 e 27/11/2011, para as quais ocorreram diferentes condições de excesso hídrico, temperatura do solo e umidade do solo. A temperatura do solo foi monitorada por sensores Pt-100, enquanto o excesso e a umidade do solo foram determinadas pelo balanço hídrico sequencial, sendo correlacionadas com a porcentagem de emergência, índice de velocidade de emergência e número de dias do subperíodo semeadura-emergência. Verificou-se que o excesso hídrico é mais prejudicial para o girassol no subperíodo semeadura-emergência, pois afeta negativamente a emergência e consequentemente, a população de plantas, reduzindo significativamente o crescimento de parte aérea e raiz, mesmo sob apenas 48 horas de excesso. Aplicado após a emergência, o excesso hídrico causa redução significativa do crescimento da parte aérea, enquanto no solo são formadas raízes secundárias e adventícias. Tanto o excesso quanto o déficit hídrico é prejudicial à emergência no campo, sendo que a umidade entre 80 e 85% da capacidade de armazenamento do solo, e a temperatura do solo de 21,5 °C são as condições mais adequadas.