Using a high throughput closed respirometry method to measure oxygen consumption, I determined metabolic rates in asexual and sexual Schmidtea mediterranea and Girardia dorotocephala, as a function of temperature, taxon, stressors, reproductive mode, age, regeneration, and specific dynamic action. This study has shown that oxygen consumption can reliably be measured in planaria using optode closed respirometry, and also provided a reliable method for measuring wet mass in planaria, which has been a challenge to researchers in the past. This research revealed that oxygen consumption in S. mediterranea is 1.5-2.1X greater in the sexual strain over the asexual strain at 13-18°C. Within the sexual strain, oxygen consumption is 1.5 -2.2X greater in sexually mature adults over the sexually immature groups (hatchlings, juveniles, and regenerating sexuals). Furthermore, I was able to quantify differences in sexual morphology between these groups exhibiting significant differences in oxygen consumption. The results of this research supports a theory of higher metabolic costs with sexual maturity in S. mediterranea. Therefore, this study has established sexual and asexual S. mediterranea as simple, yet attractive models for investigating energetic costs between sexual and asexual phenotypes. This research also provided quantitative values for specific dynamic action in planaria, with a maximum increase in oxygen consumption of 160% induced by feeding, as well as metabolic relationships in planaria involving temperature, age, and regeneration. These values establish planaria as one of the simplest animal models in which common metabolic patterns, such as SDA and poikilothermic temperature sensitivity, have been demonstrated. Therefore, this research has contributed to the overall knowledge of the basic physiology in this animal, providing the framework for future metabolic studies in planaria involving environmental factors, reproduction, regeneration, development, and aging. Information from this study may supplement interpretation and understanding of modern cellular, molecular, and genomic studies in planaria.

Surveys and vegetation analyses were used to determine the known distribution and the characteristics of the habitat utilised by Anolis sagrei in Taiwan. Sampled lizards were used for morphological comparisons, and to investigate the reproductive biology of this species in Taiwan. The results of this study indicate that the distribution of A. sagrei in Taiwan is extensive (≥237 ha) in Chiayi City and County (southwestern study site) and scattered (≥8 ha) in Hualien City and County (eastern study site). These lizards were mostly found in open sunny degraded man-made habitats. Although some variations were noted in the comparisons between the A. sagrei collected from the two study sites, it was concluded that the two populations likely have the same founder population. The reproductive biology study indicated that photoperiod and the associated temperatures determine the reproductive cycles in A. sagrei. It also demonstrated that reproduction in this species is energetically demanding. / Nature Conservation / MSc.(Nature Conservation)

Chickpea (Cicer arietinum L.) was recently introduced to the Canadian prairies, a region which has a short growing season in which crop maturation often occurs under cool and wet conditions. To improve the yield of chickpea, crop duration must closely match the available growing season. The objectives of this study were to: i) examine the days to flowering of diverse chickpea accessions grown in either long or short-days; ii) examine the days to flowering of selected chickpea accessions grown in a range of thermal regimes combined with either long or short days and to examine the interaction between photoperiod and day and night temperatures on crop duration; iii) determine the timing and duration of the photoperiod-sensitive phase in selected chickpea accessions, and vi) determine the genetic basis of the association between flowering time and reaction to ascochyta blight in chickpea. A wide variation was observed in chickpea accessions for their response to flowering under long (16/8 hours day /night) and short days (10/14 hours day/night). Earlier flowering was observed under long photoperiod regimes compared with the short photoperiod regimes. Variability was detected among chickpea accessions for their flowering responses when different temperatures were combined with different photoperiods. Earlier flowering was observed under long days (16/8 hours day/night) coupled with high to moderate temperature regimes (24/16 ºC and 20/12 ºC, day and night respectively) compared to short-days (10/14 hours day and night) and moderate to low temperature regimes (20/12 ºC and 16/8 ºC day and night, respectively). Those chickpea accessions such as ICC 6821 and ICCV 96029 which originated from the lower latitudes of Ethiopia and India, respectively, flowered earlier compared to accessions such as CDC Corinne and CDC Frontier which originated from the higher latitudes and cooler temperate environments of western Canada. Photoperiod sensitivity phases were detected in chickpea accessions adapted to the cold environments of western Canada, whereas no photoperiod sensitivity phase was identified in the extra-early flowering cultivar ICCV 96029. The duration of the photoperiod sensitive phase in the chickpea accessions was longer under short days compared to long days. Field and growth chamber evaluation of a chickpea RIL population (CP-RIL-1) revealed the presence of variability among the lines and the two parents for their days to flowering and level of resistance to ascochyta blight. Broad sense heritability across different site-years for days to flower 0.45 to 0.78, plant height 0.48 to 0.78, ascochyta blight resistance 0.14 to 0.68, days to maturity 0.26, photoperiod sensitivity 0.83 and nodes number of first flowering 0.37 to 0.75 were estimated. Days to flower and photoperiod sensitivity were significantly r = -0.21 to -0.58 (P ≤ 0.05 to 0.001) and -0.28 to -0.41 (P ≤ 0.01 to 0.001), respectively and negatively correlated with ascochyta blight resistance in the CP-RIL-1 population. A genetic linkage map consisting of eight linkage groups was developed using 349 SNP markers. Seven QTLs were identified for days to flowering under growth chamber and field conditions on chromosomes 3, 5, 6 and 8 each and 3 QTLs on chromosome 4. The total phenotypic variation explained by QTLs for days to flowering ranged from 7 to 44%. Two QTLs for days to maturity were identified on chromosomes 3 and 8. Three QTLs, one each on chromosomes 3, 4 and 5 were identified for photoperiod sensitivity. The total phenotypic variation explained by each QTL for photoperiod sensitivity ranged from 7 to 41%. A total of three QTL for node of first flowering, one on chromosomes 3 and 8 each, and two on chromosome 4 were identified. The two QTL on chromosome 4 explained total phenotypic variations of 11 and 32%, respectively. Ten QTLs distributed across all chromosomes, except chromosomes 2 and 5, were identified for ascochyta blight resistance. The phenotypic variability explained by each QTL for ascochyta blight resistance ranged from 7 to 17%. The molecular markers associated with these QTLs have potential for use in chickpea breeding.

L’intégrité fonctionnelle des organismes vivants, Homme y compris dépend des rythmes biologiques. La perturbation de ces rythmes due aux conditions de vie du monde moderne (travail posté, jet-lag,…) ou des circonstances naturelles (vieillissement), favorise l’installation de pathologies spécifiques (troubles du sommeil, l’obésité, le diabète,…). Afin de retarder l’apparition de ces troubles, la conception des projets expérimentaux sur des modèles d’animaux diurnes et des modèles d’animaux vivants dans des biotopes particuliers où l’Homme est présent (zone désertique) est nécessaire. Le but de ma thèse est d’essayer de comprendre les mécanismes neurophysiologiques d’adaptation aux conditions environnementales extrêmes chez le dromadaire (adapté à la chaleur) et le hamster d’Europe (adapté au froid). Une première partie révèle qu’en plus de la photopériode, la température ambiante est un véritable synchroniseur de l’horloge biologique du moins en absence du cycle lumière-obscurité. Dans une seconde partie, notre objectif était de vérifier si les variations saisonniers de la température ambiante sont capables comme les changements photopériodiques d’induire des modifications saisonnières sur le rythme de mélatonine et/ou de la température corporelle. Nous avons commencé par la vérification de l’existence de l’hétérothermie adaptative chez le dromadaire surtout que ce phénomène a été contesté récemment. Nos résultats démontrent que le dromadaire privé d’eau de boisson et placé sous des températures ambiantes élevées, adopte une régulation complexe de thermorégulation caractérisée par une alternance quotidienne de phase de poïkilothermie et d’homéothermie. Cet état d’hétérothermie a également été observé chez des dromadaires parfaitement hydratés, sujet d’une restriction alimentaire. Nos résultats concluent donc que l’hétérothermie adaptative chez le dromadaire est une combinaison de plusieurs facteurs qui interagissent le long du cycle lumière-obscurité, à savoir la température ambiante, la privation hydrique et la prise alimentaire. Finalement, nous avons démontré chez le hamster d’Europe que les neurones des noyaux arqués sont capables d’intégrer le signal photopériodique et cela indépendamment de la présence de la mélatonine. L’existence de ce mécanisme particulier d’intégration de la photopériode chez d’autres mammifères y compris l’Homme doit maintenant être recherchée. Nos résultats ouvrent la voie à la mise en évidence de son intérêt pratique dans le contrôle des rythmes biologiques en particulier dans celui des rythmes circannuels. / The functional integrity of living organisms, including human, depends on the biological rhythms. Disruption of these rhythms due to the living conditions of the modern world (shift work, jet lag ...) or natural circumstances (aging), leads various abnormalities (sleep disorders, obesity, diabetes ...). In order to understand pathophysiology of these abnormalities and adaptation in extreme environment, we need to design experiments on diurnal animals that cohabitate with human in specific biotopes. The aim of my thesis is to understand the neurophysiological mechanisms of adaptation to extreme environmental conditions in the camel (adapted to heat) and the European hamster (adapted to cold). Earlier we found that in addition to photoperiod, ambient temperature is a real synchronizer of the biological clock, at least in the absence of light-dark cycle. In the second part of my project, we investigated if seasonal variations of ambient temperature are capable to changes the rhythm of melatonin secretion and/or body temperature like photoperiod. Since heterothermy in camel challenged recently, we started our study by confirming the existence of adaptive heterothermy in camels. Our results demonstrate that dehydrated camels during exposure to daily heat show adaptive heterothermy. This mechanism is more complex because it is characterized by a daily alternation of two periods of poikilothermy and homeothermy. This adaptive heterothermy was also observed when camels are hydrated and food deprived. Based on our results, we can conclude that adaptive heterothermy in the Arabian camel is a combination of three factors interacting throughout the light-dark cycle: heat stress, water restriction, and level of food intake. Finally, we have demonstrated in European hamster that neurons of the arcuate nucleus are able to integrate photoperiodic signal, independent of melatonin. The existence of this particular mechanism of integration of photoperiod in other mammals including humans must be investigated. Our results promote to study the role of this new mechanism of integration of photoperiod in the control of biological rhythms in particular the circannual rhythms

Phytoplanktonarten unterscheiden sich in ihren Ansprüchen hinsichtlich Ressourcen wie Nährstoffe, Licht und andere physikalische Faktoren. Wechselwirkungen zwischen Nährstoffen und physikalischen Faktoren beeinflussen daher die Artenzusammensetzung einer Phytoplanktongemeinschaft. In der vorliegenden Arbeit wurde der Einfluss von Temperatur und Photoperiode auf das Phytoplanktonwachstum in Abhängigkeit vom Lichtregime und dem Angebot an Phosphor (P) und Silizium (Si) untersucht. Hierfür wurden Wachstums- und Konkurrenzexperimente unter Laborverhältnissen mit Stephanodiscus minutulus, Nitzschia acicularis (beides Bacillariophyceae) und Limnothrix redekei (Cyanophyceae) durchgeführt, ein Modell der Faktorinteraktionen entwickelt sowie ökologische Langzeitdaten des Müggelsees (Berlin) statistisch ausgewertet. Die Effekte von Temperatur und Photoperiode auf die Wachstumsraten unterschieden sich nicht zwischen konstantem und fluktuierendem Licht. Die Auswirkungen der Photoperiode und der Lichtfluktuationen auf die Wachstumsraten waren hierbei additiv. Der Grad der Limitation der Wachstumsraten durch P oder Si wurde durch die Photoperiode nicht signifikant beeinflusst. Wechselwirkungen zwischen Temperatur und P oder Si waren hingegen komplex und artspezifisch. Unabhängig davon, ob die Wachstumsraten durch P, Si oder fluktuierendes Licht gesteuert wurden, war S. minutulus konkurrenzstärker bei niedrigeren Temperaturen und N. acicularis bei höheren Temperaturen. Zusammenfassend zeigen die Ergebnisse, dass die Faktorinteraktionstypen artspezifisch sind, die Adaptation der Arten widerspiegeln und so zur Nischen-Differenzierung beitragen. Kenntnisse dieser Wechselwirkungen fördern deshalb unser Verständnis der Phytoplanktondiversität und ermöglichen es, Reaktionen des Phytoplanktons auf Klimaerwärmung und Trophieveränderung, die mit einer Verschiebung der Verhältnisse zwischen Nährstoffen, Temperatur und Licht einhergehen, besser vorherzusagen. / Phytoplankton species have different resource requirements and different sensitivities to important growth factors. Interactions between nutrients and physical factors, such as temperature and light should therefore influence the species composition. Because these interactions are poorly understood, this study investigated the interactive effects of temperature and photoperiod on phytoplankton growth controlled by fluctuating light, phosphorus (P) and silicon (Si). Growth and competition experiments were performed in the laboratory on Stephanodiscus minutulus, Nitzschia acicularis (both Bacillariophyceae) and Limnothrix redekei (Cyanophyceae). A model of factor interactions was developed and long-term field data from Lake Müggelsee (Berlin) were statistically analysed. Temperature and photoperiod had the same influence on growth under fluctuating light as they did under constant light. The photoperiod and short term light fluctuations caused by mixing had additive effects on growth. P and Si interacted strongly with temperature with respect to growth, but less with the photoperiod. The Droop relation fitted to S. minutulus but not N. acicularis. The Monod equation could not sufficiently account for non-steady dynamics of diatom growth under Si limitation, underestimating uptake rates and overestimating uptake affinity. Estimates based on the Monod model may therefore considerably underestimate the degree of Si limitation. The types of factor interactions were generally species-specific, reflected niche adaptation and enhanced niche differentiation. Interactions between nutrients and physical factors are relevant to growth during spring and contribute to the phytoplankton composition. Understanding the interactions should improve our knowledge of phytoplankton diversity and increase our ability to predict phytoplankton response to climate and trophic change, which shift the relationship between nutrients, temperature and light.

Cotton has been a world-wide economic staple in textiles and oil production. There has been a concerted effort for cotton improvement to increase yield and quality to compete with non-natural man-made fibers. Unfortunately, cultivated cotton has limited genetic diversity; therefore finding new marketable traits within cultivated cotton has reached a plateau. To alleviate this problem, traditional breeding programs have been attempting to incorporate practical traits from wild relatives into cultivated lines. This incorporation has presented a new problem: uncultivated cotton hampered by photoperiodism. Traditionally, due to differing floral times, wild and cultivated cotton species were unable to be bred together in many commercial production areas world-wide. This worldwide breeding problem has inhibited new trait incorporation. Before favorable traits from undomesticated cotton could be integrated into cultivated elite lines using marker-assisted selection breeding, the markers associated with photoperiod independence needed to be discovered. In order to increase information about this debilitating trait, we set out to identify informative markers associated with photoperiodism. This study was segmented into four areas. First, we reviewed the history of cotton to highlight current problems in production. Next, we explored cotton’s floral development through a study of floral transition candidate genes. The third area was an in-depth analysis of Phytochrome C (previously linked to photoperiod independence in other crops). In the final area of study, we used Genotype-By-Sequencing (GBS), in a segregating population, was used to determine photoperiod independence associated with single nucleotide polymorphisms (SNPs). In short, this research reported SNP differences in thirty-eight candidate gene homologs within the flowering time network, including photoreceptors, light dependent transcripts, circadian clock regulators, and floral integrators. Also, our research linked other discrete SNP differences, in addition to those contained within candidate genes, to photoperiodicity within cotton. In conclusion, the SNP markers that our study found may be used in future marker assisted selection (MAS) breeding schemas to incorporate desirable traits into elite lines without the introgression of photoperiod sensitivity.

Surveys and vegetation analyses were used to determine the known distribution and the characteristics of the habitat utilised by Anolis sagrei in Taiwan. Sampled lizards were used for morphological comparisons, and to investigate the reproductive biology of this species in Taiwan. The results of this study indicate that the distribution of A. sagrei in Taiwan is extensive (≥237 ha) in Chiayi City and County (southwestern study site) and scattered (≥8 ha) in Hualien City and County (eastern study site). These lizards were mostly found in open sunny degraded man-made habitats. Although some variations were noted in the comparisons between the A. sagrei collected from the two study sites, it was concluded that the two populations likely have the same founder population. The reproductive biology study indicated that photoperiod and the associated temperatures determine the reproductive cycles in A. sagrei. It also demonstrated that reproduction in this species is energetically demanding. / Nature Conservation / MSc.(Nature Conservation)