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Monks, D. P. "The vegetative and reproductive development of balansa clover." Lincoln University, 2009. http://hdl.handle.net/10182/1337.
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The vegetative and reproductive development of balansa clover (Trifolium michelianum Savi.) were quantified in relation to the environmental drivers of each phenophase in field and controlled environments. In a grazed experiment over 6 years, balansa clover sown with cocksfoot (Dactylis glomerata) contributed 1.6 t DM/ha/year, or ~20% of the total DM production. However, grazing management for increased seed production during flowering in the establishment year strongly influenced balansa clover regeneration. The earliest closed plot (September) averaged between 2.2 and 4.3 t DM/ha/year of balansa clover across all six years. In an incubator, balansa clover required 29°Cd for germination with an optimum temperature of 14°C and a maximum of 40°C. The base temperature for germination was 0°C. A field experiment determined that 38°Cd were required for emergence with an optimum soil temperature (Topt) of 8.5°C. The time from emergence until the first leaf appeared, the phyllochron and timing of axillary leaf appearance were compared with perennial ryegrass (Lolium perenne) and white clover (Trifolium repens L.). The rate of each was found to increase linearly with temperature. The balansa clover cultivar ‘Frontier’ required 97°Cd from sowing for the first leaf to appear, had a phyllochron of 47°Cd and secondary leaves appeared after 490°Cd. For each vegetative stage, the base temperature was 2.5°C. The timing of flower appearance depended on the quantity and direction of change of the photoperiod at emergence. A balansa clover plant, cv. ‘Bolta’, which emerged on 1 December into an increasing photoperiod of 15.6 hours flowered after 574°Cd (Tbase = 2.5°Cd) or 58 days after emergence. In contrast, if the plant emerged on 16 January into a similar but decreasing photoperiod it took 1503°Cd or 227 days to flower. This length of time became progressively shorter until remaining constant after the shortest day. In contrast, ‘Frontier’ took a constant 390 and 690 °Cd in increasing and decreasing photoperiods, respectively. The time which an individual inflorescence took from pollination until seeds were physiologically mature was 250 °Cd for both ‘Bolta’ and ‘Frontier’. The re-establishment of balansa clover each year relied on a large seed set (>1000 kg/ha) in the establishment year. The continued survival of balansa clover would then depend on a similar seeding event within a 4-5 year period to maintain the seed bank. Management considerations for balansa clover persistence and survival are discussed.
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Silvertooth, Jeffrey C. "Estimating the Vegetative/Reproductive Balance in Cotton Growth." College of Agriculture, University of Arizona (Tucson, AZ), 2015. http://hdl.handle.net/10150/558538.
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Coser, Sara Morra. "Breeding Acrocomia aculeata for vegetative, phenological, reproductive and productive traits." Universidade Federal de Viçosa, 2016. http://www.locus.ufv.br/handle/123456789/9438.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico
O trabalho teve como objetivo contribuir para a caracterização dos acessos de macaúba do Banco de Germoplasma de Macaúba da Universidade Federal de Viçosa à fim de colaborar com o estabelecimento do programa de melhoramento de macaúba e selecionar os acessos potencias que reúnam características a serem agregadas ao ideótipo final correspondente às necessidades do produtor e as demandas dos mercados potenciais para a espécie. Dessa maneira, os acessos foram avaliados em duas etapas. Na primeira etapa 52 acessos foram avaliados quanto a características vegetativas: altura da primeira espata (HFS), diâmetro a altura do peito (DBH), área da copa (AC); fenológicas: precocidade (PREC); e reprodutivas: total de espatas (TS); quanto a diversidade, estimação de parâmetros genéticos e estudo de correlação para a seleção dos acessos destaque para estas características. A diversidade genética resultou na formação de quatro grupos pela metodologia de Tocher que aliada aos valores de herdabilidade e coeficiente de variação representaram diversidade primordial para o melhoramento da espécie. A herdabilidade no sentido restrito, foi classificada como de magnitudes moderada (PREC, TS, CA) e alta (HFS e DBH) e os valores de acurácia foram classificados em moderados (PREC e CA) à altos (TS, HFS e DBH). A seleção de acessos para as características PREC, TS e HFS resultaram em ganhos superiores à 100% com destaque para os acessos 36, 44 e 4 de Minas Gerais. Na segunda etapa 36 acessos foram avaliados para as características precocidade (PREC), altura de emissão da primeira espata (APE), número total de frutos (NFT), teor de óleo na polpa (TOP) e produção de óleo por planta (PROD) através da estimação de parâmetros genéticos e correlação genética para realizar a predição de valores genéticos a fim de selecionar melhores indivíduos para compor a população de produção de sementes para um programa a curto prazo e a de melhoramento para um programa a longo prazo. A herdabilidade individual e a acurácia seletiva foram classificadas como de magnitude moderada para as características PREC, NTF e PROD e alta para APE e TOP, refletindo em sucesso e segurança na seleção. Os maiores valores de correlação foram encontrados entre as características PREC e APE, PREC e NTF e NTF e PROD, possibilitando ganhos indiretos através da seleção das características de mais simples mensuração. A seleção dos 20 melhores indivíduos resulta em ganhos de 74,8% em relação a média para a característica PROD para a formação do pomar de sementes a curto prazo, já a seleção dos 52 melhores indivíduos resulta em ganhos de 40,5% para a formação da população de melhoramento a longa prazo. Considerando a seleção simultânea através do índice de seleção aditivo com pesos econômicos é possível obter ganhos diretos com a seleção para a característica PROD de 67,6%. Este trabalho foi pioneiro na avaliação destas características em um banco de germoplasma de macaúba e os resultados aqui encontrados revelam diversidade genética essencial à programas de melhoramento aliada à parâmetros genéticos com excelente potencial seletivo e ganhos com a seleção, base para o sucesso do programa de melhoramento da espécie com estabelecimento de populações de melhoramento a curto e longo prazo e desenvolvimento de cultivares com ideótipo demandado pelo mercado.
The study aimed to contribute to the characterization of Macaw Palm accessions from the Germplasm Bank of Macaw Palm in Federal University of Viçosa, in order to collaborate with the establishment of macaw palm breeding program and select potential accessions that meet characteristics to be aggregated to the final ideotype corresponding to the producer needs and demands of the potential markets for the species. Thus, the accessions were evaluated in two stages. In the first stage 52 accessions were evaluated for vegetative (HFS, DBH, AC), phenological (PREC) and reproductive (TS) characteristics, for diversity, estimation of genetic parameters and correlation study aiming selection of the superior accessions for these traits. Genetic diversity resulted in the formation of four groups by Tocher methodology coupled with the heritability values and coefficient of variation represented primordial diversity for the improvement of the species. Heritability in the narrow sense was classified as moderate (PREC, TS, CA) and high (HFS and DBH) magnitudes, and accuracy values were classified from moderate (PREC and CA) to high (TS, HFS and DBH). Selection of accessions for PREC, TS and HFS resulted in gains higher than 100% especially for accessions 36, 44 and 4 from Minas Gerais. In the second stage 36 accessions were evaluated for the traits precocity (PREC), first spathe height (APE), total number of fruits (NFT), pulp oil (TOP) and oil production per plant (PROD) through the estimation of genetic parameters and genetic correlation to proceed the prediction of breeding values to select the best individuals to compose the seed production population for a short-term program and the breeding population for a long-term program. The individual heritability and selective accuracy were classified as moderate magnitude for the traits PREC, NTF and PROD and high magnitude for APE and TOP, reflecting success and security in selection process. The highest correlation coefficients were found between the traits PREC and APE, PREC and NTF, and NTF and PROD, allowing indirect gains through selection of the simpler measurement trait. The selection of the top 20 individuals results in 74.8% gains over the average of PROD trait for a short-term seed orchand formation, since the selection of the top 52 individuals results in 40.5% gains for the formation of long-term breeding population. Considering the simultaneous selection through additive selection index with economic weights is possible to obtain direct gains from selection for PROD characteristic of 67.6%. This was the first study to evaluate these characteristics in a germplasm bank of macaw palm and our findings reveal essential genetic diversity for breeding programs combined with genetic parameters with excellent selective potential and gains with the selection, the basis for the success of the breeding program for the species with the establishment of seed production population for a short-term program and the breeding population for a long-term program and the development of cultivars with the ideotype demanded by the market.
O autor não apresentou título em português.
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Herman, Bram. "The phase change from vegetative to reproductive growth in Agaricus bisporus." Thesis, University of Warwick, 2009. http://wrap.warwick.ac.uk/3152/.
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The phase change from vegetative to reproductive growth in Agaricus bisporus is a complex process involving changes in morphology at least in part regulated genetically and influenced by various environmental signals. This work was aimed at understanding how the morphology changes, and the specific environmental parameters are involved, and which genes show changes in transcription during the phase change process in A. bisporus. Different resources and methodologies were developed and applied to investigate this process including digital time-lapse photography, genome database assembly, design, validation and normalisation of a custom oligonucleotide gene expression microarray and analysis of microarray-generated gene expression profiles showing the response of this fungus under stimulatory and non-stimulatory environmental conditions. Key stages that occur during reproductive differentiation and development were identified and defined. It was found that temperature and the mushroom volatile, 1-octen-3-ol, act as an on/off switches as they block specific stages of the phase change while carbon dioxide acts as a quantitative regulator as high amounts of this molecule reduce the number of primordia and fruit bodies that develop. Gene expression profiles were constructed showing the changes in gene expression in peat-based A. bisporus samples, grown under commercial cultivation conditions which were designed to stimulate reproductive growth, and experimental cultivation conditions which were designed to separate out the effects of the three environmental parameters mentioned previously. It was found that 52 genes were differentially expressed in A. bisporus during the phase change from vegetative mycelium into fruit body primordia. A comparison with the gene expression profiles constructed for the experimental growth conditions, in correlation with morphological observations enabled the separation of these 52 genes into 3 clusters. One cluster contained 4 genes that are likely to be involved in the regulation of the “early” phase change, a second cluster contained 11 genes that are likely to be involved in the regulation of the “late” phase change and the third cluster contained 37 genes that are likely to be involved with physiological processes supporting the phase change.
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Okubo, Masataka. "Comparative study of vegetative and reproductive growth of fruit trees under salinity." Kyoto University, 2000. http://hdl.handle.net/2433/151602.
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Mingo, Darren Michael. "Regulation of vegetative and reproductive growth in plants exposed to partial root-zone drying." Thesis, Lancaster University, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.421637.
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Mahmud, Khalid. "Environmental and genotypic effects on vegetative and reproductive development in onion (Allium cepa L.)." Thesis, University of Reading, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.242124.
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Lo, Giudice Danielle. "The Impact of Prohexadione-calcium on Grape Vegetative and Reproductive Development and Wine Chemistry." Thesis, Virginia Tech, 2002. http://hdl.handle.net/10919/42768.
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Prohexadione-calcium (P-ca), as ApogeeTM, was evaluated in 2000 and 2001 for impact to grape vegetative and reproductive development. In 2000, P-ca (250 mg/L) was applied to Seyval, Cabernet Sauvignon, and Cabernet franc (125, 250, and 375 mg/L). P-ca reduced primary shoot growth for all cultivars and decreased cane pruning weight of Seyval. P-ca (375 mg/L) increased Cabernet franc canopy gaps but increased Cabernet Sauvignon lateral leaf area and leaf layer number. P-ca reduced components of yield for all cultivars. In 2001, P-ca (250 mg/L) was applied singularly at weekly intervals to Cabernet Sauvignon clusters and pre and post-bloom to Cabernet franc and Chardonnay canopies. Application at E-L stages 21 and 23 decreased Cabernet Sauvignon fruit set whereas application at E-L stages 26, 27, and 29 reduced berry weight without impacting fruit set. Berry weight reduction correlated to higher color intensity (420+520 nm), anthocyanins, total phenols and phenol-free glycosyl-glucose (PFGG). Cabernet franc vegetative and reproductive development was generally not affected yet treatment increased absorbance at 280, 420, and 520 nm, color intensity, anthocyanins and total phenols. Pre-bloom applications inhibited Chardonnay vegetative development, and reduced components of yield, and fruit chemistry values: hydroxycinnamates, total phenols, flavonoids, PPFG and absorbance at 280 and 320 nm. Post-bloom applications did not affect Chardonnay vegetative or reproductive development, yet increased PFGG. Treatment did not affect Chardonnay wine chemistry but two post-bloom applications increased Cabernet franc wine anthocyanins and total phenols. Wine aroma and flavor triangle difference tests did not indicate significant treatment differences.Master of Science
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Debenham, Gunnel Birgitta. "Bolting and flowering mechanisms in sugar beet, Beta vulgaris, ssp vulgaris (L)." Thesis, University of Nottingham, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.311840.
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Jablonski, Leanne M. "Reproductive response to elevated CO2 : the roles of vegetative carbon storage, nitrogen and seed traits." Thesis, McGill University, 1997. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=34646.
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This study focused on the reproductive response to elevated CO2 of plants possessing below-ground storage. I tested the hypotheses that under elevated CO2: (1) Plants with greater non-foliar storage capacity win show more reproductive response and (2) The altered foliar physiology of carbon (C) and nitrogen (N) use will cause increases in seed number and quality. Carbon dioxide treatments of High (650 muL L-1) and Ambient (360 muL L-1) were used in a controlled environment, simulated growing season, and in a natural pasture community. Hypothesis 1 was tested experimentally using four Raphanus varieties that differed in hypocotyl and leaf sizes. N fertilization and harvest times were used to obtain a range of root:shoot ratios. Enhancements in vegetative leaf area rather than the hypocotyl predicted reproductive responsiveness to CO 2. However, after three years of CO2 exposure in the pasture, hypocotyl-storing Taraxacum officinale responded strongly in vegetative biomass which correlated with inflorescence size and number. Fitness was enhanced four-fold, while the leaf-storing Plantago major produced more ramets and had only a two-fold fitness increase. Hypothesis 2 was tested by examining the C and N physiology underlying the vegetative organs and seeds of the pasture plants. Under elevated CO2, photosynthesis increased two-fold and senescence was delayed. Total plant C:N ratio did not differ, suggesting N acquisition increased. N similarly limited seed number in all cases suggesting an unchanged Physiology of N use in reproduction. While morphology constrained total biomass response, provisioning to seeds increased as shown by higher seed mass and number and decreased variability in number and mass. In all cases, leaf mass increase under high CO2 corresponded with fitness increase. Phenology constrained response to CO 2 as there was no plasticity in flowering day in Raphanus and Plantago, while there were flowering delays but greater seed maturation rate in Tar
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Carew, James. "Factors affecting vegetative growth and reproductive development in the primocane fruiting raspberry cv. Autumn bliss." Thesis, University of Reading, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.271195.
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Philip, Leanne Jane. "The effect of mycorrhizal fungi on the vegetative growth and sexual reproductive potential of purple loosestrife." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ43198.pdf.
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Jablonski, Leanne M. "Reproductive response to elevated CO¦2, the roles of vegetative carbon storage, nitrogen and seed traits." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape16/PQDD_0008/NQ36986.pdf.
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Okuyama, Hisashi. "Interspecific interactions and reproductive character displacement in damselflies." 京都大学 (Kyoto University), 2013. http://hdl.handle.net/2433/175151.
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Kelleher, Erin Sarah. "Evolution of Reproductive Tract Interactions in Cactophilic Drosophila." Diss., The University of Arizona, 2009. http://hdl.handle.net/10150/193629.
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Reproductive traits evolve rapidly at the morphological, physiological and molecular levels, a taxonomically robust pattern that is thought to arise from sexual selection. In internally fertilizing organisms, female promiscuity results in competition between multiple male ejaculates for fertilizations in the same female reproductive tract, extending sexual selection past courtship and copulation. In this post-copulatory arena, biochemical interaction between male ejaculates and female reproductive tracts form a dynamic molecular interface that modulates female post-mating responses essential to reproductive fitness. Consistent with the hypothesis that these interactions are subject to sexual selection, sperm and seminal proteins are known to evolve rapidly in a broad range of taxa. The female role in this process, however, in terms of both molecular mechanisms and evolutionary dynamics, remains unclear.The presented dissertation research examines the biochemical nature and evolutionary consequences of post-copulatory sexual selection in two sister-species of cactophilic Drosophila, D. mojavensis and D. arizonae. I first present data that female post-mating response in crosses between these to species is perturbed, severely reducing the reproductive output of heterospecific crosses. A breakdown of reproductive tract interactions in matings between divergent lineages suggests that male and female contributions to reproductive outcomes are coadapted. Next, I use a combination of bioinformatic analyses, comparative sequence analyses, and biochemical assays to elucidate candidate female reproductive tract proteins that may be involved in ejaculate-female dynamics. 241 candidate female reproductive proteins are identified, the most intriguing of which are recently-duplicated secreted proteases. Finally, I explore the evolutionary history of two families of secreted proteases within geographically isolated populations of D. mojavensis. I show that both families evolve rapidly through a complex process involving gene duplication, gene conversion, pseudogenation and positive selection, a unique pattern never before documented in reproductive proteins.Collectively, my dissertation research suggests that females are active participants in the evolution of reproductive tract interactions. Further exploration of how sexual reproduction coevolves between males and females, both in terms of interacting biomolecules, and dynamic evolutionary histories, remains an important challenge for future research.
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Crosby, John. "Interactions between prostaglandins, phospholipids and spermatozoa." Thesis, University of Edinburgh, 1988. http://hdl.handle.net/1842/18806.
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Mahmood, Khalid. "The effect of enviromental factors on vegetative growth and reproductive development in sweet cherry (Prunus avium L.)." Thesis, University of Reading, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.269913.
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Schupp, James R. "The influence of time of root pruning on vegetative and reproductive growth of apple (Malus X domestica Borkh.)." Connect to resource, 1985. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1133548904.
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Ben, Sadok Inès. "Developmental changes of the Olive tree from juvenility to maturity and Genetic basis of vegetative and reproductive traits." Thesis, Montpellier, SupAgro, 2013. http://www.theses.fr/2013NSAM0015/document.
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L'un des défis auxquels sont confrontés les producteurs de fruits est de réussir à maintenir d'année en année un équilibre entre croissance végétative et production. La productivité des arbres fruitiers au cours des années est étroitement liée à leur développement. Intégrer les caractères architecturaux dans les programmes de sélection pourrait donc, améliorer la régularité de production et aider à optimiser la gestion des cultures. Dans cette thèse, nous avons étudié le déterminisme génétique des caractères architecturaux chez l'olivier (Olea europaea L. subsp. Europaea), en incluant le développement végétatif et reproducteur. L'olivier a un grand intérêt en raison de l'importance de l'huile d'olive et des olives dans l'alimentation humaine. L'étude a porté sur une descendance issue du croisement entre les variétés 'Olivière' et ‘Arbequina' qui a été cultivée en verger dans deux environnements contrastés. En premier lieu, nous avons étudié le déterminisme génétique de la croissance et ramification des arbres durant la phase juvénile sur un site en considérant trois échelles d'observation: arbre, unité de croissance et entrenœuds. Les interactions entre les facteurs liés à l'ontogénie de l'arbre ainsi que les facteurs génotype et environnement ont été prises en compte. Des modèles génétiques, incluant les effets année de croissance et/ou ordre de ramification, environnement, génotype et leurs interactions respectives, ont été construits en intégrant une fonction de variance et une structure de covariance lorsque cela était nécessaire. Après une étape de sélection de modèle, les facteurs impactant significativement l'architecture de l'arbre ont été identifiés et les valeurs d'héritabilité au sens large ont été estimées. Ces résultats nous ont permis de définir à quel moment au cours de l'ontogenèse de l'olivier et à quelle échelle d'observation, les caractères de croissance et ramification sont déterminés génétiquement. De plus, cette étude a permis d'investiguer la plasticité des caractères architecturaux et leur stabilité entre environnements contrastés. Enfin, les changements associés à l'acquisition des facultés reproductives ont été observés. Quand tous les descendants ont atteint l'âge adulte, j'ai étudié les bases génétiques du développement reproducteur. La stratégie était basée sur (i) une décomposition d'un sous échantillon d'unités de croissance localisées à la périphérie de la couronne de l'arbre en variables quantitatives liées à la fois aux processus de floraison et fructification en relation avec leur croissance et ramification (ii) une évaluation annuelle du rendement des arbres durant quatre années. L'observation d'arbres 'ON' ou ‘OFF' pour une année donnée a révélé des tendances de production régulière vs irrégulière au sein de la descendance. Après avoir développé une nouvelle carte génétique, une recherche QTLs associés aux caractères reproductifs a été réalisée. Des QTLs présentant les effets des deux parents et des co-localisations ont été identifiés. Cette étude a mis en évidence le schéma de développement de l'olivier pendant les phases juvénile et mature mettant en évidence l'existence de gradients ontogéniques se traduisant par des caractères héritables qu'à la périphérie de l'arbre. Une stratégie de phénotypage adaptée aux caractéristiques architecturales de l'olivier a été proposée. Enfin, les descendants montrant une supériorité intéressante par rapport à leurs parents ont été identifiés. Ces génotypes pourraient être valorisés dans les programmes de sélection futurs pour la création de variétés innovantesOne of the most challenging questions that fruit growers are facing is to maintain trees in a stable balance between production and vegetative growth from year to year. Fruit trees productivity over years is closely linked to their development. Integrating architectural traits in breeding programs could thus, optimise cultivation management and improve bearing regularity. Here, we investigate the genetic determinism of architectural traits in the olive tree (Olea europaea L. subsp. europaea) including vegetative and reproductive behaviour. The olive tree raises high interest because of the importance of olive oil and olives in the human diet. The segregating population under study derived from a cross between ‘Olivière' and ‘Arbequina' cultivars and was grown on two orchards under contrasting environments. First, we investigated the genetic determinism of juvenile growth and branching traits in one site at three different scales: whole tree, growth unit and internodes. Interaction between tree ontogeny, genetic and environmental factors were considered. Genetic models, including the year of growth, environment, genotype effects and their interactions, were built with variance function and covariance structure of residuals when necessary. After a model selection step, morphogenetic factors impacting significantly tree architecture were identified and heritabilities were estimated. These finding allow us to define when during the olive tree ontogeny and at which observation scale, growth and branching traits are under genetic influence. Moreover, progenies plastic response to contrasted environments was highlighted and traits showing significant genotype-by-environment effect were identified. Changes over time associated to the acquisition of reproductive competence were further observed. Once all progenies attempt adulthood, we studied the genetic basis of reproductive behaviour. Our strategy was based on (i) a decomposition of adult growth units at the crown periphery in quantitative variables related to both flowering and fruiting process in relation to their growth and branching (ii) an annual assessment of individual trees yield. The observation of ‘on' or ‘off' olive trees in a given year over four years revealed patterns of regular vs. irregular bearing. After developing a new genetic map, a QTL mapping was carried out on reproductive traits, leading to the identification of QTLs with effects from both parents and co-localizations. This study gives an overview of olive tree development during juvenility and maturity periods showing the existence of ontogenic trends, which result in traits heritable mostly at the tree periphery. A phenotyping strategy adapted to its architectural characteristics is proposed. Finally, progenies showing interesting superiority in comparison to their parents were identified and could constitute interesting sources for innovative materials in future selection programs
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Burmeister, Matt. "Influence of seed source on vegetative and reproductive performance of three common prairie grasses common in grassland restoration /." View online, 2008. http://repository.eiu.edu/theses/docs/32211131464751.pdf.
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Ibrahim, Abdelaziz Ali Mohamed 1948. "Vegetative, reproductive and yield responses of tomato (Lycopersicon esculentum L.) seedlings to low temperature and exogenous sucrose treatments." Thesis, The University of Arizona, 1994. http://hdl.handle.net/10150/278454.
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The effects of subjection of 15-day-old plants of tomato (Lycopersicon esculentum L. 'Contessa') to low night temperature (LNT) of 4°C for up to 21 nights and pre-chilling application of 10% sucrose solution on vegetative, reproductive and yield responses were examined under greenhouse conditions. Chilled seedlings exhibited severe inhibition of growth, with the degree of inhibition increasing with length of chilling. While sucrose treatment (ST) reduced such inhibition and promoted subsequent recovery, it transiently inhibited growth of the unchilled controls. In the long-term, inhibition of growth was observed only for the 0%-sucrose-treated plants cooled for 21 nights. Although LNT lowered the position of the first inflorescence in a direct relation to duration of exposure, this effect was reduced by ST. LNT had no lasting effects on the reproductive and productivity responses of the first two inflorescence (FTI), earliness of flowering, or potential yield and quality. ST promoted flowering of only the 21-day-cooled plants as well as numbers of flowers, fruit set and large fruit responses of FTI. The results indicate that, although early chilling stunts seedling growth, plants may recover at a later favorable temperature without loss to their reproductive capacity or yielding potential.
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Espagne, Eric. "Contribution à l'étude des systèmes non alléliques d'incompatibilité végétative chez le champignon filamenteux Podospora anserina." Bordeaux 2, 2000. http://www.theses.fr/2000BOR28739.
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Floyd, Jr Stephen Preston. "Cheating and Selfishness in Reproductive Interactions among Nest Associative Cyprinids." Thesis, Virginia Tech, 2016. http://hdl.handle.net/10919/80977.
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Mutualism is an understudied interaction in ecosystems throughout the world. Within the eastern United States, one fish-fish mutualism is the nest association between Nocomis and other cyprinids. I assessed the role of host parental care while testing for the selfish-herd effect. Additionally, I examined multiple nest associates in order to elucidate potential cheaters. I utilized gonadosomatic index (GSI) to compare reproductive condition among the bluehead chub Nocomis leptocephalus and its putative nest associates in Catawba Creek, Virginia. GSI of potentially obligate associates tracked host GSI more closely than weak associates, while weak associates spawned prior to Nocomis spawning. Given their GSI patterns and behavior, central stonerollers Campostoma anomalum may be cheaters in the interaction. I used multiple experiments to test for the selfish-herd effect, the role of parental care, and how relative risk influences reproductive decisions of associates. Most eggs were located in the bottom upstream quarter of nests, and a molecular analysis revealed that stonerollers and chubs constituted the majority of identified individuals. A comparison of host-associate ratios from four nest sections failed to identify the selfish herd effect. Another experiment found that host egg covering significantly reduced egg predation. Lastly, I assessed relative egg predation risk at four potential spawning locations; predation levels did not differ significantly at any location. While GSI patterns suggest that stonerollers may be cheaters, genetic evidence indicates that stonerollers spawn on Nocomis nests. Because GSI does not completely assess reproduction, secondary stoneroller reproduction on Nocomis nests may have been overlooked.Master of Science
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Cutri, Lucas 1983. "Estudo da função do gene leafy (LFY) em duas especies de Passiflora." [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/315305.
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Orientador: Marcelo Carnier DornelasDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia
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Resumo: O gene LEAFY (LFY) específico de plantas, além de atuar na transição do meristema vegetativo para o reprodutivo, parece regular também a transição do desenvolvimento de produtos do meristema apical tão diversos quanto: folhasgavinhas; flores-gavinhas e inflorescências-flores solitárias, além de diminuir drasticamente o tempo necessário para que a planta passe da fase vegetativa para a fase reprodutiva. O gênero Passiflora é um candidato em potencial para o estudo da evolução da função biológica do gene LFY, por conter todas as estruturas morfológicas em que o referido gene atua. Neste estudo, foram analisadas duas espécies divergentes de Passiflora: Passiflora edulis var flavicarpa e Passiflora suberosa. O desenvolvimento reprodutivo de ambas foi caracterizado com o uso de microscopia óptica e de microscopia eletrônica de varredura. Análises moleculares da função do gene LFY também foram executadas nestas duas espécies. Isolou-se, via PCR, fragmentos potencialmente correspondentes a homólogos do referido gene em P. edulis e em P. suberosa. Estas seqüências gênicas, denominadas respectivamente PeLFY e PsLFY foram utilizadas em análises filogenéticas. O padrão de expressão de ambos os genes foi investigado em experimentos de RTPCR e hibridização in situ em diferentes tecidos durante o desenvolvimento das espécies de Passiflora estudadas Adicionalmente, foram obtidas plantas transgênicas de P. suberosa, contendo uma construção de superexpressão do gene LFY de Arabidopsis
Abstract: The LEAFY (LFY) gene is plant-specific, and besides playing a role in the transition of the vegetative to the reproductive meristems, it seems to regulate the development of different products of the shoot apical meristem (SAM) as leaves-tendrils, flowerstendrils, solitary flowers-inflorescences. It is also responsible for decreasing substantially the time needed for the transition from the vegetative to the reproductive phase. The genus Passiflora is a good model for the study of the evolution of the biologic function of the LFY gene, because it has all morphological structures in which this gene acts. In this study, two distinct species: Passiflora edulis var. flavicarpa and Passiflora suberosa had their reproductive development analyzed by optical microscopy and scanning electron microscopy. Molecular analyzes of LFY functions were also performed in both species. Fragments corresponding to homologs of the LFY gene were cloned from P. edulis and P. suberosa by PCR. These fragments were named PeLFY and PsLFY, respectively and were used in filogenetic analyzes. The expression patterns of these genes were investigated by RT-PCR and in situ hybridization in different tissues of the studied Passiflora species. Additionally, transgenic lines of P. suberosa were obtained that contained a construction that promoted the overexpression of the Arabidopsis LFY gene
Mestrado
Mestre em Biologia Vegetal
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Renda, da Costa Paula MR. "A Quantified Approach to Tomato Plant Growth Status for Greenhouse Production in a Semi Arid Climate." Diss., The University of Arizona, 2007. http://hdl.handle.net/10150/194440.
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Balancing plant growth between vegetative and reproductive status is crucial for producing high quality greenhouse tomatoes while maintaining high productivity in long crop production seasons. In the tomato industry, certain plant morphological characteristics are used to classify plant growth status as vegetative, reproductive or balanced. Each growth status has been associated with distinct greenhouse environments which reduce or enhance transpiration.The effect of different transpiration on vegetative, reproductive or balanced plant growth status as defined by a set of plant morphological characteristics was investigated. To validate the practical significance of such classification, growth status was quantified as the relationship between variations in morphological characteristics and the fresh weight distributed between reproductive and vegetative organs.Two electrical conductivity (EC) levels of the nutrient solution, high and standard EC, were combined with two potential transpiration environments, low and high potential transpiration. All treatment combinations were contrasted with a reference greenhouse environment similar to the industry standard.Electrical conductivity had the greatest effect on morphological characteristics which were reduced in size with high EC. For each EC level, the response decreased for increasing potential transpiration. Stem diameter had the greatest sensitivity to the different treatment combinations. For the standard EC and for the range of potential transpirations achieved, stem diameter varied within a relatively narrow range, close to the industry standard 'threshold' used to classify a balanced tomato plant. A reproductive plant growth status, as evaluated by a smaller value than this threshold, was observed only with high EC. No vegetative plants were produced within any potential transpiration or EC treatment combination.High EC decreased the cumulative total fresh weight production by the same magnitude for all potential transpirations. Potential transpiration had a minimal effect on the total fresh weight production or on its components. As a result, the fresh weight ratio between reproductive and vegetative plant organs was similar for most potential transpiration environments, regardless of variations in stem diameter. Therefore, within the range of potential transpiration environments achieved, the distinction between vegetative and reproductive growth status as an indicator of fresh weight distribution and fruit yields could not be quantitatively validated.
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Sorensen, George Edwin Peter. "Host-virus interactions in porcine reproductive and respiratory syndrome virus infection." Thesis, University of Edinburgh, 2014. http://hdl.handle.net/1842/10040.
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Porcine reproductive and respiratory syndrome virus (PRRSV) is a rapidly evolving virus that has significant economic and welfare implications for the pig industry. Vaccination strategies have proved largely ineffective in controlling PRRSV, in some cases even reverting to virulence. An increasing body of evidence suggests a host genetic basis for PRRSV resistance so there is a need to examine the role of host genetics in a biologically relevant in vitro cell culture system. However, PRRSV research is inhibited by the current scarcity of suitable in vitro culture systems. With the aim of developing a convenient in vitro model, porcine bone marrow-derived macrophages (BMDM) were evaluated as a PRRSV cell culture system. BMDM were found to be highly permissive to Type I PRRSV and amenable to genetic manipulation. BMDM proved to be excellent cells for virus production, producing significantly higher titres of PRRSV than commonly used alternative cell types. Surprisingly, PRRSV entry into BMDM was found to be independent of both the prototypic PRRSV receptors, CD163 and CD169, providing further evidence for the existence of alternate PRRSV entry mechanisms in primary cell types. To explore the genetics of pig susceptibility to PRRSV, network-based analysis of host transcriptional datasets, following PRRSV challenge, revealed important differences in co-regulated gene pathways between samples from pigs with different PRRSV-permissiveness. These pathways included genes with important, recently characterised, anti-pathogen activities. The incorporation of network-based transcriptional analysis and published genetic variation data led to the identification of a member of the guanlyate binding protein family, GBP-1, as a candidate host gene involved in controlling PRRSV replication. Overexpression of GBP-1 in BMDM revealed a significant anti-PRRSV function for this protein. Further investigation of published genetic variation in GBP-1 suggested a potential role of this gene in PRRSV tolerance. The results presented in this thesis provide evidence for an alternate PRRSV entry pathway in a biologically relevant cell type. The discovery of a highly PRRSV-infectable cell type with potential for genetic manipulation adds a useful new tool to the area of PRRSV research. The identification of GBP-1 as a novel anti-viral protein with a significant inhibitory effect on PRRSV infection, together with genetic variation in this gene, prompts further research into the genetic basis for PRRSV resistance.
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Hull, Scott D. "The relationships among vegetative structure, arthropod populations, and grassland bird abundance and reproductive success on wildlife production areas in Ohio /." The Ohio State University, 2002. http://rave.ohiolink.edu/etdc/view?acc_num=osu1486457871784286.
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Keller, Markus. "Partitioning response of Vitis vinifera L. to environmental stress : vegetative and reproductive growth as affected by nitrogen availability under limiting irradiance /." [S.l.] : [s.n.], 1995. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=11004.
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Volschenk, Theresa. "The effect of saline irrigation on selected soil properties, plant physiology and vegetative reproductive growth of Palsteyn appricots (Prunus armeniaca L.)." Thesis, Stellenbosch : University of Stellenbosch, 2005. http://hdl.handle.net/10019.1/1196.
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Thesis (PhD (Soil Science))--University of Stellenbosch, 2005.Approximately 45% of apricot tree plantings in South Africa are centered on Montagu, Koo and Barrydale in the Little Karoo. Below average production in this area could be ascribed to the deteriorating water quality of the Breede River and highly saline groundwater from boreholes which provide this area with irrigation water. Profit margins for farmers are such that decreased yields cannot be tolerated. Correct management of low quality water could improve production and net farm income and could decrease irrigation return flow into the river system. The objective of this work was to establish whether international water quality guidelines for apricot are applicable under a different set of climatic conditions for a locally important cultivar and to revise guidelines if necessary for the management of irrigation with saline water. A drainage lysimeter was used to evaluate the effect of saline irrigation on apricot (Prunus armeniaca cultivar Palsteyn) trees over a period of four years at Stellenbosch (S33° 55’; E18° 53’) in the Western Cape.
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Souza, Cleber Henrique Lopes de. "Produção e qualidade de sementes de Paspalum guenoarum Arech. ecótipo “Azulão” submetido a diferentes regimes de corte no segundo ano de cultivo." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2015. http://hdl.handle.net/10183/128127.
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O objetivo deste trabalho foi avaliar o efeito do número de cortes na produção e qualidade de sementes de Paspalum guenoarum ecótipo “Azulão” no segundo ano de cultivo. Foram avaliados quatro tratamentos de corte: zero (testemunha), um, dois e três cortes quando o dossel das plantas atingia altura de 40 cm. O delineamento experimental foi de blocos completos casualizados, com quatro repetições. As parcelas tinham 7,2 m² (3,6 m x 2 m) com as plantas em linhas espaçadas a 0,4 m. As avaliações foram semanais de dezembro de 2013 a março de 2014. As variáveis estudadas foram: número de perfilhos/planta, número de perfilhos reprodutivos/planta através de amostragens não destrutivas. O número de racemos/inflorescência, número de sementes/inflorescência, número de sementes/racemo, peso de mil sementes, rendimento de sementes/área, germinação e índice de velocidade de germinação, foram obtidos através de amostragens destrutivas após a colheita das sementes. As médias foram comparadas pelo teste de Tukey a 5%. O tratamento de um corte (719 kg.ha-1 de sementes e 75% de plântulas normais) não diferiu da testemunha, não apresentando impactos negativos na produção e qualidade de sementes. Entretanto, a partir de dois cortes, houve a diminuição do número de perfilhos reprodutivos/planta, adiamento da colheita e redução da produção de sementes. A realização de um corte permitiu a produção de boa quantidade de forragem (2500 kg.ha-1 de MS) sem prejudicar o rendimento e a qualidade das sementes.This study was aimed to evaluate the effect of the number of cutting in seed production and quality of Paspalum guenoarum, “Azulão” ecotype on the second year of crop. Treatments of zero (control), 1, 2, and 3 cuts were evaluated. The experimental design was a completely randomized block with four repetitions. The plots were of 7.2 m² (3.6 m x 2 m) with plants in 0.4 m rows spacing. Assessments were performed weekly from December, 2013 to March, 2014. The studied variables were number of tillers/plant, number of reproductive tillers/plant, and number of racemes/inflorescence through nondestructive sampling. The number of seeds/inflorescence, number of seeds/raceme, weight of thousand seeds, seed yield/area, germination, and germination speed index were obtained through destructive sampling after harvesting seeds. The means were compared by Tukey test at 5%. One cutting treatment (719 kg.ha-1 of seeds and 75% normal seedlings) doesn’t differ significantly comparing to the control, so, it didn’t appear negative impacts in seed production and quality. However, from two different cutting, there was a decrease in the number of reproductive tillers/plant, causing a delay harvest and reduced seed production. The achievement of one cutting allowed a utilization of good quantity of forage (2500 kg.ha-1 DM) without harming significantly the seed yield and quality.
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Lee, Sang-Myeong. "Interactions of porcine reproductive and respiratory syndrome virus with innate immune responses." Diss., Columbia, Mo. : University of Missouri-Columbia, 2005. http://hdl.handle.net/10355/5817.
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Thesis (Ph. D.)--University of Missouri-Columbia, 2005."December 2005" The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Vita. Includes bibliographical references.
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Larrick, Stephanie. "Interactions between age and the reproductive fitness of Culex quinquefasciatus (Diptera: Culicidae)." [Gainesville, Fla.] : University of Florida, 2009. http://purl.fcla.edu/fcla/etd/UFE0024841.
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Yamane, Hideyuki. "Reproductive strategies and interspecific interactions in nest-association systems of freshwater fishes." 京都大学 (Kyoto University), 2011. http://hdl.handle.net/2433/142416.
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Tatsiopoulou, Angeliki. "Effects of manipulation of light quality in the greenhouse environment with photoselective films on vegetative and reproductive growth of contrasting horticultural crops." Thesis, University of Reading, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.417326.
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D'Alessandro, Joseph. "Collective regulation of the amoeboid motility : the role of short and long-range interactions in vegetative Dictyostelium discoideum." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSE1039/document.
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La motilité cellulaire est fondamentale dans de nombreux processus physiologiques, qu’ils soient normaux ou pathologiques. Cependant, bien que ces derniers impliquent la plupart du temps de nombreuses cellules se mouvant en même temps, les effets des interactions entre cellules sur leur dynamique, à la fois individuelle et collective, restent assez mal connu. Dans cette thèse, j’ai utilisé Dictyostelium discoideum à l’état végétatif pour étudier cette régulation collective de la motilité. Je me suis principalement appuyé sur une analyse minutieuse de nombreuses trajectoires cellulaires dans des situations variées pour (i) caractériser un facteur sécrété qui régule négativement la motilité cellulaire (nature chimique, voie de signalisation, dynamique de sécrétion et de réponse) et (ii) analyser et modéliser quantitativement la dynamique d’étalement de colonie cellulaires de forme, dimension et densité contrôlées. Je décris enfin un phénomène d’agrégation dynamique observé lorsque les cellules sont placées à haute densité dans un milieu nutritifCell motility is fundamental in many physiological, either normal or pathological, phenomena. Yet, although these most often involve several cells moving at the same time, how the interactions between cells affect both individual and collective dynamics remains a poorly understood question. In this thesis, I used vegetative Dictyostelium discoideum cells as a model to study this collective regulation of the motility. I relied mainly on the thorough analysis of numerous cell trajectories in various situations to (i) characterise a secreted factor used to down-regulate the cells’ motility (biochemical nature, response pathway, secretion and response dynamics) and (ii) quantitatively analyse and model the dynamics of spreading cell colonies of controlled initial shape, size and density. Last, I describe a dynamic aggregation phenomenon that occurs when the cells are seeded at high density in a nutrient-rich medium
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Lievens, Eva J. P. "Biotic challenges for extremophiles : reproductive interference and parasite specialization in Artemia." Thesis, Montpellier, 2016. http://www.theses.fr/2016MONTT146/document.
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Les défis posés par des facteurs biotiques – les interactions avec des compétiteurs, des parasites, etc. – jouent un rôle important dans l’évolution des populations, mais sont souvent difficiles à étudier. Dans cette étude, nous avons utilisé le système biologique Artemia dans les salins d’Aigues-Mortes, France, pour étudier le caractère et l’évolution de plusieurs interactions interspécifiques. Le système est particulièrement bien adapté à cette recherche : il est simple, contenant deux espèces d’Artemia, trois parasites fortement prévalents (un helminthe et deux microsporidies), et des microbiota variés ; et beaucoup des interactions du système ont été nouvellement établies, car une des espèces d’Artemia est invasive. Nous avons étudié deux types d’interactions. Premièrement, la présence et l’évolution de l’interférence reproductive entre les espèces native et invasive d’Artemia. Nous avons trouvé que l’espèce invasive, qui est sexuée, subit une interférence sévère en allocation des sexes en présence de l’espèce native et asexuée, mais pas d’interférence en gardiennage de partenaire. Deuxièmement, l’évolution de la spécialisation de deux parasites microsporidiennes qui infectent les espèces d’Artemia. En nous basant sur des données de terrain, des infections expérimentales, et de l’évolution expérimentale, nous avons investigué l’état, les causes, et les conséquences de la spécialisation des microsporidies. Les résultats démontrent que les microsporidies sont spécialisées dans l’utilisation d’une des espèces d’hôte, même si elles sont capables de compléter leur cycle de vie dans chacun des deux hôtes. Cette spécialisation paraît être imposée par les outils précis nécessaires à l’exploitation de chaque hôte ; dans les hôtes non-spécialistes, ils provoquaient de l’exploitation sous-optimale, de la virulence maladaptative, et de l’immunopathologie. En général, ces études suggèrent que les facteurs biotiques imposent des pressions de sélection fortes sur Artemia, auxquelles elles ne peuvent pas toujours répondre facilement. L’importance des facteurs biotiques dans un système qui est autrement dominé par des conditions abiotiques extrêmes souligne l’importance des interactions interspécifiques dans l’évolutionThe challenges posed by biotic factors – interactions with competitors, parasites, etc. – play a large role in the evolution of populations, but are generally difficult to study. In this work, we used the Artemia system in the hypersaline salterns of Aigues-Mortes, France, to study the character and evolution of several interspecific interactions. The system is eminently suited to such studies: it is simple, containing two Artemia species, three highly prevalent parasites (one helminth and two microsporidians), and various microbiota; and many of its interactions are newly-established, because one of the Artemia species is invasive. We studied two types of interactions. First, the presence and evolution of reproductive interference between the native and invasive Artemia species. We found that the invasive Artemia species, which is sexual, undergoes severe interference in sex allocation when in the presence of the native, asexual Artemia, but no interference in mate guarding. Second, the evolution of parasite specialization in two microsporidian parasites infecting the Artemia species. Using field data, experimental infections, and experimental evolution, we investigated the state, causes, and consequences of specialization in the microsporidians. Results consistently indicated that the microsporidians are specialized for one host species, despite being able to complete their life cycle in either host. This specialization appears to be imposed by the precise toolkits needed to exploit each host species; in the non-specialized hosts, these triggered suboptimal exploitation, maladaptive virulence, and immunopathology. Overall, these studies suggest that the biotic factors acting on Artemia impose strong selection pressures, to which they cannot always respond easily. The importance of biotic factors in a system which is otherwise dominated by extreme abiotic conditions underlines the importance of species interactions in shaping evolution
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Lazarotto, Diana Carla. "Fitotoxidez do óleo essencial de Heterothalamus psiadioides LESS sobre Arabidopsis thaliana (L.) HEYNH." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2014. http://hdl.handle.net/10183/106416.
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O arbusto Heterothalamus psiadioides Less. (Asteraceae) ocorre no sul do Brasil e no Uruguai, se estabelecendo frequentemente em formações densas. Esse padrão de estabelecimento pode estar relacionado a efeitos alelopáticos dos voláteis liberados por essa planta. Portanto, este trabalho objetivou investigar os efeitos do óleo essencial de H. psiadioides sobre a germinação, crescimento inicial, enraizamento adventício e desenvolvimento vegetativo e reprodutivo de Arabidopsis thaliana (L.) Heynh., planta-alvo desse estudo. Além disso, a caracterização química do óleo essencial foi realizada. Para avaliar efeitos sobre a germinação e o crescimento inicial, sementes e plântulas de A. thaliana foram expostas aos voláteis de H. psiadioides, cuja composição química foi analisada através de cromatografia em fase gasosa associada à espectrometria de massas. Para avaliar efeitos sobre o enraizamento adventício, plântulas de A. thaliana tiveram suas raízes primárias cortadas, gerando microestacas que foram expostas aos voláteis. Além disso, tratamentos para recuperação dos efeitos causados pelos voláteis foram utilizados – com adição de auxina, citocinina e antioxidante ao meio de cultura. No experimento que testou os efeitos dos voláteis sobre o desenvolvimento reprodutivo e vegetativo da planta-alvo, as plantas foram expostas aos voláteis dentro de câmaras de vidro. Após a exposição e quando as plantas senesceram, parâmetros vegetativos e reprodutivos foram avaliados. A germinação e o crescimento inicial da planta-alvo foram afetados negativamente pelos voláteis de H. psiadioides. Da mesma forma, o enraizamento adventício das plantas foi afetado. Microestacas da planta-alvo expostas aos voláteis demoraram mais tempo para enraizar, desenvolveram menos raízes e essas eram mais curtas do que as microestacas controle. Estresse oxidativo foi detectado nas microestacas expostas aos voláteis; além disso, hormônios e antioxidante não reverteram os efeitos fisiológicos negativos causados pelos mesmos. A avaliação do desenvolvimento vegetativo e reprodutivo das plantas expostas aos voláteis nas câmaras de vidro permitiu detectar efeitos negativos dos voláteis apenas em um parâmetro relacionado ao crescimento, que foi mensurado logo após o período de exposição. Nenhum outro parâmetro diferiu significativamente entre plantas expostas aos voláteis e não expostas. Esses resultados indicam que apesar dos drásticos efeitos demonstrados pelos voláteis sobre sementes e plântulas, efeitos pouco relevantes foram encontrados para o desenvolvimento vegetativo e reprodutivo. Portanto, possivelmente o potencial alelopático de H. psiadioides pode ser menor do que o esperado, já que plantas juvenis a adultas são capazes de recuperar-se dos efeitos dos voláteis dessa planta.The shrub Heterothalamus psiadioides Less. (Asteraceae) occurs in Southern Brazil and Uruguay, where it often establishes in dense populations. This pattern of establishment may be related to allelopathic effects of the volatiles released by this plant. Therefore, this study aims to investigate the effects of the volatile essential oil of H. psiadioides on germination, early growth, adventitious rooting and vegetative and reproductive development of Arabidopsis thaliana (L.) Heynh., the target plant of this study. Furthermore, the chemical characterization of the essential oil was performed. To assess effects on germination and early growth, seeds and seedlings of A. thaliana were exposed to H. psiadioides volatiles, which had the chemical composition analyzed by gas chromatography coupled to mass spectrometry. To evaluate effects on adventitious rooting, seedlings of A. thaliana had the primary roots excised, generating microcuttings that were exposed to the volatiles. Moreover, treatments to recovery the effects caused by the volatiles were used – with addition of auxin, cytokinin and antioxidant in the culture medium. In the experiment that tested the effects of the volatiles on the vegetative and reproductive development of the target plant, plants were exposed to the volatiles inside of glass chambers. After the exposition and at senescence, vegetative and reproductive parameters were evaluated. The germination and early growth were negatively affected by the volatiles. Adventitious rooting was similarly affected. Microcuttings of the target plant exposed to the volatiles were slower to root, less developed and had shorter roots in relation to control microcuttings. Oxidative damage was detected in the microcuttings exposed to the volatiles; furthermore hormones and antioxidant did not revert negative physiological effects caused by the oil. The evaluation of vegetative and reproductive development of plants exposed to the volatiles inside of glass chambers allowed to detect negative effects just in a parameter measured immediately after removal plants from the chambers. Other parameters did not differ between plants exposed to the volatiles and plants not exposed. These results indicate that despite of drastic effects showed by the volatiles on seeds and seedlings, effects of little relevance were found in vegetative and reproductive development. Therefore, it is possible that allelopathic potential of H. psiadioides may be lower than expected, since juvenile and adult plants are able to recover from the effects of the plant volatiles.
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Carter, Lucy Mary. "Evolutionary ecology of reproductive strategies in malaria parasites." Thesis, University of Edinburgh, 2014. http://hdl.handle.net/1842/9910.
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For vector-borne parasites such as malaria, how within- and between-host processes interact to shape transmission is poorly understood. In the host, malaria parasites replicate asexually but for transmission via mosquitoes to occur, specialized sexual stages (gametocytes) must be produced. Once inside the mosquito vector, gametocytes immediately differentiate into male and female gametes, and motile male gametes must swim through the hostile environment of the bloodmeal to find and fertilise female gametes. Despite the central role that gametocytes play in disease transmission, explanations of why parasites adjust gametocyte production in response to in-host factors remain controversial. Furthermore, surprisingly little is known about the mating behaviour of malaria parasites once inside the mosquito. Developing drugs and/or vaccines that prevent transmission by disrupting sexual stages are major goals of biomedicine, but understanding variation in gametocyte investment and male gamete behaviour is key to the success of any intervention. First, I propose that the evolutionary theory developed to explain variation in reproductive effort in multicellular organisms provides a framework to understand gametocyte investment strategies in malaria parasites. I then demonstrate that parasites appear to change their reproductive strategies in response to environmental cues and in a manner consistent with our predictions. Next, I show how digital holographic microscopy can be used to characterise the morphology and motility of male gametes. I then provide evidence for non-random movement of male gametes and that gamete interactions with red blood cells appear to hinder mating success in a bloodmeal. Finally, I discuss the variation in gametocyte differentiation and fertilisation success when exposed to a number of factors implicated in gametocyte activation. The data presented here provides important information on the basic biology of malaria parasite reproductive stages and demonstrates considerable variation in parasite traits and behaviours in response environmental changes; both in the host and in the mosquito vector.
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Jones, Maren Bell. "Effects and interactions of endocrine disrupting chemicals and diet on the mouse reproductive system." Diss., Columbia, Mo. : University of Missouri-Columbia, 2007. http://hdl.handle.net/10355/5006.
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Thesis (M.A.)--University of Missouri-Columbia, 2007.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on October 29, 2007) Vita. Includes bibliographical references.
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Chandrasekhar, Yallampalli. "Interactions between thyroid hormones and reproductive function in prepubertal and sexually mature merino rams /." Title page, contents and summary only, 1985. http://web4.library.adelaide.edu.au/theses/09PH/09phc4567.pdf.
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Hocking, Michael. "Social interactions and reproductive behaviour of the fat-tailed dunnart, Sminthopsis crassicaudata, in captivity /." Title page, contents and abstract only, 1996. http://web4.library.adelaide.edu.au/theses/09SPS/09spsh685.pdf.
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Montanari, Serena. "Microsatellite variation and reproductive interactions of common and Egyptian soles in Mediterranean sympatric demes." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2011. http://amslaurea.unibo.it/1802/.
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Feek, Colin Michael. "Adrenal → gonad interactions in the male rat : studies on the influence of the adrenal gland on testicular steroidogenesis." Thesis, University of Edinburgh, 1987. http://hdl.handle.net/1842/18875.
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Stolk, Robert. "The effect of irrigation and canopy management on selected vegetative growth and reproductive parameters of Vitis vinifera L. cv. Shiraz in the Breede River Valley." Thesis, Stellenbosch : Stellenbosch University, 2014. http://hdl.handle.net/10019.1/86470.
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Thesis (MScAgric)--Stellenbosch University, 2014ENGLISH ABSTRACT: The objective of the study was to determine combined effects of irrigation and canopy management practices on grapevine water status, growth, yield and juice characteristics. The field study was carried out with Shiraz/110R grapevines in the Breede River Valley. Grapevines were drip irrigated at 30%, 60% and 90% plant available water (PAW) depletion, respectively. For each PAW level, grapevines had (i) suckered, vertical shoot positioned (VSP), (ii) non-suckered, VSP and (iii) sprawling canopies. Treatments were replicated three times in a randomised block design and applied during the 2011/12 and 2012/13 seasons. Irrigation applied at low PAW depletion levels, i.e. high frequency irrigation, required substantially higher irrigation volumes compared to high depletion levels, i.e. low frequency irrigation. Low frequency irrigation increased grapevine water constraints compared to high frequency irrigation. Sprawling canopy grapevines experienced more water constraints than VSP grapevines. Grapevines irrigated at 90% PAW depletion experienced strong water constraints. Low frequency irrigation seemed to accelerate berry ripening compared to high frequencies, probably due to smaller berries and lower yields. Sprawling canopies consistently enhanced berry ripening due to more sunlight interception by the leaves. Berry ripening of VSP grapevines was slower, but inconsistent between seasons. Level of PAW depletion and canopy management practice did not affect number of leaves per primary shoot. Low frequency irrigation reduced number of leaves per secondary shoot. Leaf number per shoot contributed more to total leaf area than leaf size. Level of PAW depletion did not affect number of shoots per grapevine. Suckering reduced number of shoots per grapevine. Low frequency irrigation reduced total leaf area per grapevine compared to high frequency irrigation. Effects of canopy management practice were more pronounced in the case of high frequency irrigation compared to low frequency irrigation. At pruning, primary cane length was not affected by level of PAW depletion or canopy management practice. Secondary cane mass and diameter were not affected by canopy management practice. Multiple linear regression showed that cane mass was a function of cane length and diameter. Low frequency irrigation reduced berry mass compared to high frequency irrigation, irrespective of canopy management practice. However, at harvest there was no difference in berry mass between 30% and 60% PAW depletion. Low irrigation The objective of the study was to determine combined effects of irrigation and canopy management practices on grapevine water status, growth, yield and juice characteristics. The field study was carried out with Shiraz/110R grapevines in the Breede River Valley. Grapevines were drip irrigated at 30%, 60% and 90% plant available water (PAW) depletion, respectively. For each PAW level, grapevines had (i) suckered, vertical shoot positioned (VSP), (ii) non-suckered, VSP and (iii) sprawling canopies. Treatments were replicated three times in a randomised block design and applied during the 2011/12 and 2012/13 seasons. Irrigation applied at low PAW depletion levels, i.e. high frequency irrigation, required substantially higher irrigation volumes compared to high depletion levels, i.e. low frequency irrigation. Low frequency irrigation increased grapevine water constraints compared to high frequency irrigation. Sprawling canopy grapevines experienced more water constraints than VSP grapevines. Grapevines irrigated at 90% PAW depletion experienced strong water constraints. Low frequency irrigation seemed to accelerate berry ripening compared to high frequencies, probably due to smaller berries and lower yields. Sprawling canopies consistently enhanced berry ripening due to more sunlight interception by the leaves. Berry ripening of VSP grapevines was slower, but inconsistent between seasons. Level of PAW depletion and canopy management practice did not affect number of leaves per primary shoot. Low frequency irrigation reduced number of leaves per secondary shoot. Leaf number per shoot contributed more to total leaf area than leaf size. Level of PAW depletion did not affect number of shoots per grapevine. Suckering reduced number of shoots per grapevine. Low frequency irrigation reduced total leaf area per grapevine compared to high frequency irrigation. Effects of canopy management practice were more pronounced in the case of high frequency irrigation compared to low frequency irrigation. At pruning, primary cane length was not affected by level of PAW depletion or canopy management practice. Secondary cane mass and diameter were not affected by canopy management practice. Multiple linear regression showed that cane mass was a function of cane length and diameter. Low frequency irrigation reduced berry mass compared to high frequency irrigation, irrespective of canopy management practice. However, at harvest there was no difference in berry mass between 30% and 60% PAW depletion. Low irrigation.
AFRIKAANSE OPSOMMING: Die doelwit van hierdie studie was om die gekombineerde effek van besproeiing en lowerbestuurspraktyke op wingerd waterstatus, groei, opbrengs en druiwesap eienskappe te bepaal. Die veld studie is uitgevoer met Shiraz/110R wingerdstokke in die Breede Rivier Vallei. Wingerdstokke was d.m.v. drupbesproeiing teen 30%, 60% en 90% plant beskikbare water (PBW) ontrekking, onderskeidelik besproei. Vir elke PBW ontrekkingspeil, was wingerdstokke (i) gesuier en vertikale lootposisionering toegepas, (ii) ongesuier en vertikale lootposisionering toegepas en (iii) geen lowerbestuur toegepas nie (lowers wat oophang). Behandelings is drie keer in ‘n ewekansige blokontwerp herhaal en tydens die 2011/12 en 2012/13 seisoene toegepas. Besproeiing wat teen ‘n lae PBW ontrekkingspeil toegedien is, d.w.s. hoë frekwensie besproeiing, vereis aansienlik hoër besproeiings volumes i.v.m. hoë besproeiing ontrekkingspeile, d.w.s. lae frekwensie besproeiing. Wingerdstokke wat oopgehang het meer watertekorte as vertikaal lootgeposisioneerde wingerdstokke ervaar. Wingerdstokke wat teen 90% PBW ontrekking besproei was, het sterk watertekorte ervaar. Dit het voorgekom of lae frekwensie besproeiing korrelrypwording versnel het i.v.m. hoë frekwensie besproeiing. Dit was heelwaarskynlik a.g.v. kleiner korrels en laer opbrengste. Wingerdstokke wat oophang het, het konsekwent korrelrypwording versnel a.g.v. meer sonligonderskepping deur die blare. Korrelrypwording van vertikaal lootgeposisioneerde wingerdstokke was stadiger, maar teenstrydig tussen die seisoene. Plant beskikbare water ontrekkingspeil en lowerbestuurspraktyke het geen invoeld gehad op die aantal blare per primêre loot nie. Lae frekwensie besproeiing het die aantal blare per sekondêre loot verminder. Die hoeveelheid blare per loot het ‘n groter bygedra gemaak i.v.m. blaar grootte. Plant beskikbare water ontrekkingspeil het geen invloed gehad op die aantal lote per wingerdstok nie. Suier verminder die aantal lote per wingerdstok. Lae frekwensie besproeiing verminder die totale blaar oppervlak i.v.m. hoë frekwensie besproeiing. Die effek van lowerebestuurspraktyke is duideliker sigbaar by hoë frekwensie besproeiing i.v.m. lae frekwensie besproeiing. Primêre lootlengte was nie deur PBW ontrekkingspeil of lowerbestuurspraktyke beïnvloed nie. Sekondêre lootmassa en -deursnit is nie deur lowerbestuurspraktyk beïnvloed nie. Meervoudige lineêre regressie het getoon dat lootmassa ‘n funksie van lootlengte en -deursnit was. Lae frekwensie besproeiing het korrelmassa verminder ongeag die lowerbestuurspraktyk i.v.m. hoë frekwensie besproeiing. Daar was egter geen verskil in korrelmassa by oes tussen 30% en 60% PBW ontrekking nie. Lae frekwensie besproeiing was geneig om suiker akkumulasie te versnel i.v.m. hoë frekwensie besproeiing. Wingerdstokke wat oopgehang het, het veral by lae frekwensie besproeiing korrelrypwording versnel i.v.m. vertikaal lootgeposisioneeide wingerdstokke. Suikerinhoud per korrel het geneig om toe te neem totdat dit ‘n plato bereik het. Hierdie plato was meer prominent by hoë frekwensie besproeiing i.v.m. lae frekwensie besproeiing. Wingerdstokke wat oopgehang het, het ook hierdie plato vroeër bereik i.v.m. vertikaal lootgeposisioneerde wingerdstokke. By oes was die totale titreerbare suur (TTS) hoër vir wingerdstokke wat vroeër geoes was. As gevolg van versnelde rypwording was TTS van wingerdstokke wat teen lae frekwensie besproei is hoër i.v.m. hoë frekwensie besproeiing. ‘n Ligter oeslading in verhouding tot ‘n hoër blaaroppervlak het ook gelei tot hoër TTS by oes. Plant beskikbare water ontrekkingspeil en lowerbestuurspraktyke het geen invloed op die pH gehad met oes nie. Die hoeveelheid trosse per wingerdstok het nie duidelike tendense gewys wat verbind kon word met watertekorte wat deur die stokke ervaar is nie. Gesuierde vertikaal lootgeposisioneerde wingerdstokke het die hoeveelheid trosse per stok verminder i.v.m. die ongesuierde vertikaal lootgeposisioneerde wingerdstokke en wingerstokke wat oopgehang het. Trosmassa het dieselfde tendense as korrels per tros gevolg. Lae frekwensie besproeiing het opbrengs aansienlik verminder i.v.m. hoë frekwensie besproeiing. Gesuierde vertikaal lootgeposisioneerde wingerdstokke het geneig om opbrengste te verminder i.v.m. ongesuierde vertikaal lootgeposisioneerde wingerdstokke. Hierdie effek het egter verdwyn waar wingerdstokke teen 90% PBW ontrekking besproei was. Druif skade a.g.v. suurvrot was meer prominent by hoë frekwensie besproeiing, veral vir ongesuierde vertikaal lootgeposisioneerde wingerdstokke. Total opbrengs verlies, uitgedruk as ‘n persentasie, was hoofsaaklik ‘n funksie van sonbrand eerder as ‘n funksie van suurvrot.
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Fontana, Anna [Verfasser], Jonathan [Akademischer Betreuer] Gershenzon, Monika [Akademischer Betreuer] Hilker, and Wolfgang W. [Akademischer Betreuer] Weisser. "The Roles of Vegetative Volatiles in Plant Defense and Other Interactions / Anna Fontana. Gutachter: Jonathan Gershenzon ; Monika Hilker ; Wolfgang W. Weisser." Jena : Thüringer Universitäts- und Landesbibliothek Jena, 2011. http://d-nb.info/1016368437/34.
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Zhang, Xing. "Biogeography and biosystematics of plum curculio, Conotrachelus nenuphar (Herbst)/Wolbachia interactions." Diss., Virginia Tech, 2006. http://hdl.handle.net/10919/25948.
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This research focused on the reproductive incompatibility and genetic differences between the two strains of plum curculio, Conotrachelus nenuphar (Herbst). Two molecular markers served as the basis for the strain distribution analysis of plum curculio and Wolbachia symbiont. One marker is the partial mitochondrial cytochrome oxidase gene subunit I (mtCOI) of plum curculio. Another marker is the Wolbachia Surface Protein (wsp) gene of Wolbachia associated with plum curculio. First, the reproductive compatibility of cross-populations mating in plum curculio was studied during the summers of 2004 and 2006. The results confirmed the reproductive incompatibility among plum curculio geographic populations. A unidirectional incompatibility was revealed in an approximate north and south transect of the range of plum curculio (4 x 4 two factorial design: NY, VA, FL, and WV): there was a significant low fertility in WV males mated with NY (40%) and VA (29%) females. The Florida population showed a different pattern: FL males have a significantly lower fertility with VA (46%) and WV (37%) females while FL females were compatible with all males from the four populations. The results of experiment 2 indicated that within the northern geographic area populations (3 x 3 two factorial design: NY, MA, and NJ) were compatible with each other. An opposite unidirectional reproductive incompatibility was revealed in the combination of NJ males with FL females, which showed a significant low fertility (47%). A bi-directional incompatibility occurred between FL and WV reciprocal cross mating. FL males mated with WV females (26%) and WV males mated with FL females (21%) both have the significant low fertility compared to fertility of within their population matings.
The genetic diversity among plum curculio populations from different geographic locations was investigated using the partial mtCOI gene. A total of 50 samples from 10 populations were sequenced. PCR products were 863 bp in length. A total of 23 unique sequence haplotypes were found in the 50 samples tested. Haplotype G (n = 5), L (n = 12) and T (n = 13) comprised 60% of 50 samples. The nucleotide distances between those haplotypes ranged from 0.12% to 4.87%. Genetic distances between northern and southern group plum curculios range from 4.17% to 4.87%. Two distinct major clades were found, using three different phylogenetic analyses: 1) neighbor joining (NJ), 2) maximum-parsimony (MP), and 3) maximum-likelihood (ML). 100% bootstraps support the northern clade and the southern clade was strongly supported (100/100/86, NJ/MP/ML) as well. The mid-southern subclade within the southern clade was also strongly supported (70/82/71, NJ/MP/ML) and the far-southern subclade was supported in NJ tree (81%) but was not resovled in MP and ML trees. The mid-southern subclade included haplotypes from two NJ, Washington, VA (Ra), Blacksburg, VA (BL) and 50% of WV populations and the far-southern subclade included haplotypes from FL, GA, Whitethorne, VA (Ke), Troutville, VA (Bo) and another 50% of WV populations. The results suggested that the northern and the southern clade could correspond with the northern and southern strains, respectively, of plum curculio. In this study, the mtCOI sequence was highly informative as a molecular marker in that it was useful to distinguish C. nenuphar from northern and from southern geographic locations in the eastern United States. However, the number of generations per year of several geographic populations within the southern clade still needs to be determined.
The distribution of Wolbachia infection associated with plum curculio strains was investigated. 91 of 93 samples were infected by Wolbachia. Three unique Wolbachia strains were identified. The strains wCne1 and wCne2 (593 bp) were 97% identical, and their sequences were both 84% identical with wCne3 (590 bp). The wsp sequence of wCne1 was 99% identical to Wolbachia sequenced from the neotropical beetle, Chelymorpha alternans Boheman (Keller et al. 2004). The wCne2 sequence was 98.5% identical to the flower bug, Orius nagaii Yasunaga (Miura and Tagami, unpublished). The wCne3 sequence was 100% identical to Wolbachia sequenced from the tephritid fruit fly, Dacus destillatoria (Jamnongluk et al. 2000) and the ant, Formica exsecta (Reuter and Keller 2003). PCR - Restriction Fragment Length Polymorphism (RFLP) was used for superinfection detection. Of 93 samples, 15 (16.1%), 21 (22.6%), 19 (20.4%), 36 (38.7%) samples were infected by wCne1, wCne2, wCne1 plus wCne2, and wCne3, respectively. Only two (2.2%) samples had no infection. The wCne3 strain was always present as a single infection. Therefore, current results suggest that Wolbachia strains approximate the distribution of plum curculio strains: the northern strain is infected with wCne1 and wCne2 strains in supergroup B, the southern strain is infected with wCne3 strain in supergroup A and the mid-Atlantic region is the convergence area. Compared with the haplotype distribution of plum curculio mtCOI gene, there was a closer relation of the mid-southern PC clade to the far-southern clade than to the northern clade. However, Wolbachia symbionts in mid-southern PC are more closely related to those in northern PC than to those in far-southern PC. The relationship of Wolabchia infection with reproductive incompatibility between plum curculio populations is also discussed.Ph. D.
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Rousseau, Ludivine Blandine. "Reproductive strategies of Weddell seals in McMurdo Sound, Antarctica: relationship among vocalizations, behaviors, and social interactions." Texas A&M University, 2003. http://hdl.handle.net/1969.1/5776.
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Phocid seals (true seals, Order Carnivora, Family Phocidae) use a diverse array
of breeding habitats and strategies, and produce many vocalizations. Therefore, phocids
are well suited as subjects for study of reproductive strategies and the role of
vocalizations in species mating at sea. However, the amount of information is still
limited for aquatically breeding pinnipeds. Using underwater audio and video recordings
of Weddell seals (Leptonychotes weddellii) interacting in McMurdo Sound, I compared
the frequencies of vocalizations and behaviors of males and females during the mating
season. I also investigated differences in these frequencies based on the social context.
Finally, I identified patterns of vocalizations and behaviors to help determine the
behavioral context of calls and used this information as a basis for considering the
degree of ritualization in Weddell seal displays. Mews, growls, knocks, and trills were
found to be almost exclusively male-specific. The territorial male produced chirps more
often when another male was present in its territory; whereas, mews and growls were
more frequent when one or more free-ranging females were present. Several vocal and
behavioral padeparture of the territorial male into or from the breathing hole. In the context of an
evolutionary-based model of communication, these findings suggest that low-frequency
vocalizations and stereotyped displays produced by territorial males may have been
favored by sexual selection: they may provide reliable information to females about the
fitness of the signaler and influence their choice of mate. They may also help in limiting
conflicts between the territorial male and females over access to the breathing hole.
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Taschen, Elisa. "Interactions biotiques et biologie reproductive de la Truffe noire, Tuber melanosporum (Vittad.) : des truffières spontanées aux plantations." Thesis, Montpellier, 2015. http://www.theses.fr/2015MONTS111/document.
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La Truffe noire (Tuber melanosporum Vittad.) est un champignon ectomycorhizien spontanément présent dans les groupements végétaux ouverts en cours de reforestation. Alors que ces milieux ont fortement régressé au XXème siècle dans la zone méditerranéenne, 80 % de la production actuelle provient de boisements artificiels où des arbres inoculés par la Truffe sont plantés. Malgré un grand corpus de connaissances empiriques, la production reste souvent aléatoire et les connaissances fondamentales d'écologie et de biologie de la Truffe restent fragmentaires. Dans ce travail, nous avons d'abord étudié la distribution de la diversité fongique ectomycorhizienne sur les différents hôtes présents dans les garrigues pré-forestières à Truffe. Nous avons ensuite testé les interactions entre la Truffe et les plantes endo- ou non-mycorhiziennes, qui se matérialisent par la création d'un brûlé, où la flore est localement affectée. Dans un troisième volet, nous avons cherché à mieux comprendre la diversité génétique des populations de Truffes, et plus spécifiquement l'appariement sexuel et la dispersion de cette espèce à vie végétative haploïde et à fructification hypogée. Par une approche comparative entre truffières plantées et spontanées, nous avons finalement évalué les modifications liées au processus de proto-domestication en cours. Ainsi, en combinant écologie des communautés, expériences en conditions contrôlées et génétique des populations, nous avons montré qu'en région méditerranéenne :1) La Truffe est présente de façon fugace dans des communautés ectomycorhiziennes riches, avec de nombreuses espèces multi-hôtes, mais où la Truffe montre une préférence d'hôte marquée pour le chêne vert (Q. ilex). 2) Certaines plantes endo- ou non-mycorhiziennes, dont l'effet positif sur la Truffe a empiriquement été observé par les trufficulteurs, favorisent le développement du mycélium de Truffe dans le sol, agissant indirectement sur les interactions plante-plante (chêne – plantes endomycorhiziennes). L'effet inhibiteur de la Truffe observé sur la germination des graines peut-être une des causes précoces du brûlé. Par ailleurs, la Truffe semble effectivement coloniser les racines de plantes herbacées non-ectomycorhiziennes.3) Les flux de gènes sont limités à l'échelle de la truffière, l'appariement sexuel réunit des individus proches génétiquement et physiquement, et bien que la Truffe soit probablement hermaphrodite, les parents paternels sont peu détectables, probablement de taille plus réduite que les parents maternels (formant la gléba). Les pratiques culturales pourraient entraîner un brassage génétique plus important en plantation, mais à l'échelle régionale, aucune différence de diversité génétique n'a été détectée entre populations spontanées et cultivées. Ce travail montre la richesse des interactions biotiques impliquant la Truffe et les diversités végétale et fongique des truffières artificielles et spontanées de la région méditerranéenne. Les résultats acquis contribuent à lever le voile sur sa biologie reproductive, et jalonnent le chemin pour des pratiques intégratrices de la diversité biologique des truffières, ainsi que pour le développement de futures expérimentations in situ. Mots clés : appariement sexuel, Arbutus unedo, Cistus albidus, domestication, écologie des communautés, forêts méditerranéennes, génétique des populations, isolement par la distance, ITS, microsatellites, mésocosmes, mycorhizes, pratiques empiriques, qPCR, Quercus coccifera, Quercus ilex, successions secondairesThe Black Truffle (Tuber melanosporum Vittad.) is an ectomycorrhizal fungus spontaneously growing in open woodlands before canopy closure. Such open landscapes drastically regressed during the last century in the Mediterranean regions, and nowadays 80% of the production comes from man-made plantations where the Truffle is inoculated. Despite a large corpus of local knowledge and empirical practices, the production remains largely sporadic and unpredictable, and our knowledge of the biology and ecology of the Truffle is still fragmentary. In this work, we first analyzed the distribution of the ectomycorrhizal fungal diversity among host plants co-existing in the shrub-dominated landscapes where Truffle naturally occurs. We then analyzed the interactions between the Truffle and endo- or non-mycorrhizal plants, as they typically occur in the so-called brûlés, zones with scarce vegetation. A third part aimed at better understanding the genetic diversity of Truffle populations, with special focus on fertilization and dispersal process of this fungus with haploid lifecycle and hypogeous fruiting. In a multi-scale approach combining community ecology, experimentation and population genetics, we found that in the Mediterranean region:1) The Truffle is transiently present in rich ectomycorrhizal communities, showing a significant host preference for Q. ilex, in assemblies made of numerous multi-host fungal species. 2) Some endo- or non-mycorrhizal plants species, that were supposed to provide beneficial effect on the Truffle, can be experimentally shown to stimulate the development of T. melanosporum mycelium in soil, and indirectly trigger plant-plant interactions (between oak and endomycorrhizal plants). The early brûlé symptoms could at least partially result from a Truffle's inhibitor effect on seed germination.3) At truffle ground scale, gene flow is limited, and mating occurs between genetically and physically close parents. Despite probable hermaphroditism of the Truffle, paternal parents are poorly detectable, certainly of smaller size than maternal ones (these forming nourishing tissue of the ascocarp). Cultural practices could favor genetic mixing/diversity at brûlé scale, but at the regional scale, no difference in genetic diversity was found between spontaneous and planted compartments.This work revealed the richness of biotic interactions involving the black Truffle and the plant as well as the fungal diversity in both artificial and spontaneous truffle-ground of the Mediterranean region. These results enlighten the reproductive biology of the species, and pave the way for practices integrating the biological diversity of truffle-grounds and the development of further in situ experimentations. Key words: Arbutus unedo, Cistus albidus, community ecology, domestication, empirical practices, local knowledge, experimental approach, inbreeding, isolation by distance, ITS, Mediterranean forests, mesocosms, microsatellites, mycorrhiza, population genetics, qPCR, Quercus ilex, Q. coccifera, secondary successions
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Jones, Meagan E. "Female Humpback Whale (Megaptera novaeangliae) Reproductive Class and Male-Female Interactions during the Breeding Season." Antioch University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=antioch1292617002.
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Ortega-Beltran, Alejandro. "Ecology, Distribution, Toxigenicity and Diversity of Aflatoxin-Producing Fungal Communities in Maize Fields of Mexico and Interactions of these Fungi with Native Maize Landraces." Diss., The University of Arizona, 2012. http://hdl.handle.net/10150/265833.
Full textAbstract:
Aflatoxins are carcinogenic mycotoxins most frequently associated with the filamentous fungus, Aspergillus flavus. These potent toxins pose serious health threats and their concentrations in foods are widely regulated. Maize, a critical staple of billions, is frequently contaminated with aflatoxins. Development of commercial maize hybrids with superior resistance to aflatoxin contamination has been sought for over 30 years without success. Analyses of native maize land races (MLRs) from Mexico revealed several accessions with significant resistance to both aflatoxin contamination and fungal reproduction. Physical barriers are important components of MLRs resistance. Traditional use of MLRs may reduce human exposure to aflatoxins. MLRs may contribute resistant genes of significant value in breeding for aflatoxin resistance. In Mexico, maize is produced from<10 to over 2,000 masl. Elevation had only minor influence on community compositions of aflatoxin-producing fungi associated with maize over three years in Sonora, Mexico. Most variation in community structure occurred between years. Dominant vegetative compatibility groups (VCGs) differed among years but were detected in similar frequencies across four agroecological zones. Multiple locations and multiple years must be sampled to obtain realistic assessments of the most successful VCGs. Elevated frequencies of VCG YV150 throughout Sonora during 2006 led to investigate genetic diversity within this VCG using microsatellite loci. The 2006 increases were attributed to rapid increase of a single clone. Examination of YV150 isolates collected over 20 years in the US and Mexico revealed several haplotypes and two genetically distinct populations, which were composed of isolates containing only a population specific mating-type idiomorph. Microsatellite loci in each population were in gametic equilibrium. Gene flow between isolates with different idiomorphs was not detected. VCG YV36, to which the biocontrol agent AF36 belongs, was found to be endemic to Mexico. Microsatellite loci revealed diversity within YV36 from Mexico, but all isolates harbored the single nucleotide polymorphism in the aflatoxin polyketide synthase gene, pksA, that confers atoxigenicity to AF36. Three YV36 isolates also had deletions in pksA suggesting continued degradation. Presence of endemic YV36 isolates in Mexico may facilitate rapid regulatory approval of AF36 for use in prevention of aflatoxin contamination of maize in Mexico.