1 |
Variabilité intraspécifique de l’efficience d’utilisation de l’eau dans une famille de chêne pédonculé (Quercus robur L.) : causes physiologiques et/ou anatomiques / Variability of water-use efficiency in a pedunculate oak (Quercus robur L.) family : physiological and/or anatomical causesRoussel, Magali 14 October 2008 (has links)
Le chêne pédonculé est une espèce présentant une forte variabilité intra-spécifique d'efficience d'utilisation de l'eau (WUE) dont le déterminisme génétique a été démontré. WUE est un caractère complexe qui, à l'échelle foliaire, est défini par le rapport entre le taux d’assimilation nette de CO2 (A) et la conductance stomatique pour la vapeur d’eau (gs). Ce rapport - estimé par la composition isotopique en 13C de la matière organique (?13C)- est influencé par une multitude de facteurs physiologiques et structuraux qui conditionnent A (quantité de chlorophylle, épaisseur des différents tissus…) et gs (densité stomatique…). La comparaison pour ces traits foliaires de génotypes issus d'une même famille de plein-frères de chêne pédonculé, en conditions non-limitantes, a permis de montrer que la variabilité de WUE, dans cette famille, était surtout liée à gs et non aux capacités photosynthétiques. Pour approfondir ce travail, une étude a été menée sur la possibilité d'utiliser les variations de composition isotopique en oxygène (16O/18O) de l'eau foliaire et de la matière organique foliaire pour décomposer des différences d'efficience d'utilisation de l'eau en composantes photosynthétiques et transpiratoires. Les résultats de cette étude laissent envisager la possibilité d’utiliser l'outil isotopique 18O comme estimateur de gs chez le chêne pédonculé, mais seulement en conditions contrôlées, et après améliorations des techniques d’extractions de la matière organique. / Pedunculate oak is a species that shows a large intraspecific variability of water-use efficiency (WUE). The genetic determinism of WUE in this species has been demonstrated. WUE is a complex trait which is defined at a leaf level as the ratio of net CO2 assimilation rate (A) on stomatal conductance for water vapor (gs). This ratio – estimated with carbon isotope composition of organic matter (?13C) – is therefore influenced by numerous physiological or anatomical traits that influence A (chlorophyll content, thickness of leaf tissue) or gs (stomatal density…). The comparison of genotypes belonging to a same full-sib family of pedunculate oak, in non-limiting conditions, for these foliar traits has shown that the variability of WUE in this family was linked to the variability of gs instead of photosynthetic capacity. To go further, a study has been done on the possibility to use the variations of the isotope composition of oxygen (16O/18O) of leaf water and leaf organic matter to decompose the differences in water-use efficiency in its photosynthetic and transpiratory components. The results of this study has shown that the 18O signature coulb be used as a proxy for gs for pedunculate oak, but only in controlled conditions, and after amelioration of organic matter extraction procedures.
|
2 |
Herstellung und Evaluation genetisch veränderter Masernviren zur spezifischen Infektion und Elimination primärer maligner Plasmazellen / Genetically engineered attenuated measles virus specifically infects and kills primary multiple myeloma cellsHummel, Horst-Dieter January 2010 (has links) (PDF)
Das Multiple Myelom ist trotz deutlicher Fortschritte in der Therapie meist eine unheilbare Erkrankung, so dass der Erforschung neuer therapeutischer Optionen mit dem Ziel, eine möglichst langfristige krankheitsfreie Zeit für den betroffenen Patienten zu erreichen, eine wichtige Bedeutung zukommt. Hierbei erweist sich der Ansatz, maligne Plasmazellen spezifisch mit onkolytischen Viren zu infizieren und zu eliminieren, als zunehmend vielversprechend. Im Rahmen dieser Arbeit wurde ein neues rekombinantes Masernvirus kloniert, das selektiv primäre MM-Zellen infiziert und abtötet. Diese Fähigkeit basiert auf der Verwendung eines mutierten H-Proteins, das nicht mehr mit den natürlichen Rezeptoren CD46 oder CD150 interagiert und das zusätzlich mit einem single chain Antikörper (scFvWue) verknüpft ist, der MM-Zellen spezifisch bindet. Unter Verwendung eines etablierten Rescuesystems aus cDNA konnten in vitro replikationskompetente Virionen von MV-Wue erstellt werden. Diese vorgenommenen Veränderungen beeinflussten die Fähigkeit zur effizienten Replikation und Produktion infektiöser Viren in vitro nicht. Zur funktionellen Testung des neuen rekombinanten Virus MV-Wue wurde die Spezifität des Virus für primäre maligne Plasmazellen in Infektionsexperimenten gezeigt sowie der Mechanismus der Ablation als Apoptose definiert. / The applicability of cytoreductive treatment of malignant diseases using recombinant viruses strongly depends on specific recognition of surface receptors to target exclusively neoplastic cells. A recently generated monoclonal antibody (mAb), Wue-1, specifically detects CD138(+) multiple myeloma (MM) cells. In this study, a haemagglutinin (H) protein that was receptor-blinded (i.e. did not bind to CD46 and CD150) was genetically re-engineered by fusing it to a single-chain antibody fragment (scFv) derived from the Wue-1 mAb open reading frame (scFv-Wue), resulting in the recombinant retargeted measles virus (MV)-Wue. MV-Wue efficiently targeted and fully replicated in primary MM cells, reaching titres similar to those seen with non-retargeted viruses. In agreement with its altered receptor specificity, infection of target cells was no longer dependent on CD150 or CD46, but was restricted to cells that had been labelled with Wue-1 mAb. Importantly, infection with MV-Wue rapidly induced apoptosis in CD138(+) malignant plasma cell targets. MV-Wue is the first fully retargeted MV using the restricted interaction between Wue-1 mAb and primary MM cells specifically to infect, replicate in and deplete malignant plasma cells.
|
3 |
Analýza vláhové potřeby polních plodin v oblasti s častým výskytem sucha. / Analysis of water requirements of the field crops in areas with frequent occurrence of drought.Zábranský, Petr January 2016 (has links)
Summary
Water resources are an important part of ecosystems. In the water balance of the landscape, the variability of climate, soil factors, as well as high diversity of vegetation play an important role. Evapotranspiration represents a major passive component in the water balance of the basin. Unlike forests, where the water balance is particularly predictable due to the long-term development of the stands, regular crop rotation in agricultural systems and agricultural practices may cause rapid changes in water balance during much shorter time. It may sometimes result in irreversible changes in ecosystems with impact on landscape biodiversity. An understanding of the limiting environmental factors and exact determination of the water demands of plants makepossible not only an improvement of yield parameters, but it is also condition for understanding of the agroecosystems sustainability in the cultural landscape.
Field measurements of actual evapotranspiration were carried out in the period 2007 to 2015 in Velvary (Budihostice) in the Central Bohemia region, 210 m above sea level in the rain shadow area around Slaný territory. In terms of the average annual water balance (CHMI, 2014), the locality is regarded as the area with the difference between the average annual precipitation and annual potential evapotranspiration totals in amount of -200 mm, so the potential evapotranspiration slightly exceeds precipitation. Field measurements were conducted on commonly managed areas with a minimum size of the experimental plots of 1 ha.
The measurements confirmed differences between the crop water demands during the growing season. Different values of the actual evapotranspiration as well as the Bowen ratio values were estimated for the observed crops depending on the growth stage of crops. The lowest values of actual evapotranspiration were detected for Zea mays and Sorghum bicolor. Higher water demands were shown by Triticum aestivum and Hordeum vulgare. On the contrary, the highest values of actual evapotranspiration were found in stands of Beta vulgaris and Medicago sativa. According to the values obtained for crop coefficients (Kc), the crops of Z. mays, S. bicolor and T. aestivum had about a quarter lower values of Kc compared with M. sativa and B. vulgaris crops in the main growing season. In this work, the daily values of Kc, which are the basic characteristics of moisture requirements for individual crop were determined and can be used modelling of hydrological processes in agro-phytocoenoses. The evaluation of moisture requirement of crops by the water flow in plants (determined by the sap flow method) showed the expected differences between S. bicolor and Z. mays plants. Water use efficiency (WUE) was significantly higher in plants of C4 type (Z. mays and S. bicolor) compared with the rest of observed plants of C3 type (T. aestivum and H. vulgare).
|
4 |
Steuerung von Bewässerungssystemen im Gewächshaus mit Hilfe des PhytomonitoringExarchou, Evanthia 13 April 2006 (has links)
Der verstärkte Wassermangel und die ökologische Belastung durch Düngemittel und Pestizide erfordert eine kontrollierte und präzise Applikation von Wasser und Nährlösung. Die messtechnische Ermittlung des Wasserhaushalts im SPAC-System erfolgt durch Messungen an den einzelnen Komponenten Boden, Pflanze und Atmosphäre. Eine stärkere Aussagekraft über den tatsächlichen Wasserstatus der Pflanze bietet die sensorische Informationsgewinnung an der Pflanze selbst (Phytomonitoring). Ein neuentwickelter Phytomonitor (EPM 2005 bzw. 2006), der auf dem Prinzip einer Gaswechselmessung an einzelnen Pflanzenblättern basiert, wurde zur Messung der momentanen Transpirationsintensität von Pflanzenbeständen eingesetzt. Die Präzision und Repräsentativität der Methode wurde in unterschiedlichen Jahreszeiten unter mitteleuropäischen (Berlin, Deutschland) und südeuropäischen Gewächshausbedingungen (Thessaloniki, Griechenland) getestet. Als Vergleichsbewässerungsverfahren wurden die Saugspannungsregelungsmethode und die Bewässerung nach Zeitsteuerung herangezogen. Gleichzeitig wurden Tensiometer zur Überwachung des Saugspannungsverlaufs im Substrat eingesetzt. Im Vergleich zu weiteren Phytomonitoringsystemen ist dadurch eine bessere Übertragbarkeit der Messdaten auf größeren Pflanzenbeständen gegeben. Die Methode ist dabei nicht sortenspezifisch. Durch ein hohes Bestimmtheitsmaß der Regressionsfunktion der gemessenen Transpirationsmassenstromdichte bzw. Nettophotosyntheseleistung an zwei Standorten der gleichen Konditionen wurde die Homogenität des pflanzlichen Stoffaustausches in Gewächshausbeständen bewiesen. Die Übertragbarkeit der Messdaten auf den gesamten Bestand wurde durch die Bildung der Wasserbilanz über längere Zeitperioden geprüft. Hohe Korrelationen wurden zwischen den gemessenen und den berechneten Transpirationssummen erzielt. Die Bewässerungssteuerung nach den gemessenen Transpirationssummen hat die vorbestimmte Überschussmenge, sogar unter hohen Strahlungs- und Luftfeuchtigkeitsbedingungen, erzielen können. Der durch Tensiometer registrierte Saugspannungsverlauf eines transpirationsgesteuerten Tomatenbestands war vergleichbar zu dem eines tensiometergeregelten Bestandes. Die zwei Bewässerungsmethoden ergaben keine signifikante Unterschiede in der Fruchtanzahl, Blattanzahl oder Pflanzengröße. Das Wasser wurde leicht effizienter in dem tensiometergeregelten Bestand eingesetzt, ohne dass sich die Erträge signifikant unterschieden. Minimalste Drainagemengen ( / The increased shortage of water, were as the ecological pollution through fertilisers and pesticides, requires a controlled and precise amount of water inset. The determination of the water balance in the SPAC-System by technological measurements is reached by measuring on the individual components substrate, plant and atmosphere. The direct measuring on the plant by the Phytomonitoring-Technology is meaningful for the determination of the factual water status of the plant. A new developed Phytomonitoring (EPM 2005 or 2006), which is based on gas exchange measurements of individual plant leaves by cuvettes, was used for measuring the momentary transpirations intensity of plant cultures. The precision and representatively of the method was tested on different seasons under north European (Berlin, Germany) and south European (Thessaloniki, Greece) greenhouse conditions. The tensiometer control method as well as a time-scheduled irrigation system were used for comparison purposes. Tensiometers were used for monitoring the suction course in the substrate. In comparison to other Phytomonitoring-systems gives this one a better transmissibility of the measurement on big canopies. A high coefficient of determination of the regression line between the measured transpirations intensity (and photosynthesis intensity) of two sites with the same conditions, was found. This improves the homogeneity of the mass exchange in greenhouse canopies. Water balances were builded over long periods to prove the transmissivity of the measurements over the whole canopy. The measured transpiration sums were high correlated to the calculated ones (through the water balance equation). The drain target of 20-30% (usual for the practical experience) of the irrigation scheduling method, based on the measured transpiration sum, could be reached even under high radiation and low humidity conditions. The substrate of a tomato stand irrigated after the transpirationsummethod (switch threshold: 3 l transpiration sum, irrigation amount: 4 l) showed a suction-course comparable to the one of a tensiometercontroled stand (switch threshold: 50 hPa, irrigation amount: 3 l). There were no significant differences in the fruit number, leaf number or planthight between the two canopies. The water was efficiently consummated in the tensiometercontroled stand, were as the yields were significantly not different. Minimal drain water amounts (
|
5 |
Fiziološke adaptacije bukve (Fagus sylvatica L.), smrče (Picea abies (L.) Karsten) i jele (Abies alba Mill.) na sezonsko variranje abiotičkih činilaca u četiri zaštićena planinska staništa Republike Srbije / Physiological adaptations of beech (Fagus sylvaticaL.), spruce (Picea abies (L.) Karsten) and fir (Abies alba Mill.) on seasonal variation of abiotic factors in four protected mountain habitats in the Republic of SerbiaHorak Rita 28 May 2015 (has links)
<p>Tokom tri vegetacione sezone mereni su fiziološki<br />parametri: fotosinteza, transpiracija, efikasnost<br />iskorištavanja vode (WUE), kao i parametri<br />bioprodukcije na odabranim šumskim<br />populacijama bukve (Fagus sylvatica L.), smrče<br />(Picea abies (L.) Kartsen) i jele (Abies alba Mill.),<br />čija su staništa na različitim nadmorskim visinama<br />sa različitom dostupnošću vode u zemljištu.<br />Određivana je i zavisnost između položaja šumske<br />zajednice na padini planine (nadmorska visina i<br />nagib) i fotosinteze, odnosno bioprodukcije<br />biljaka. Cilj istraživanja je bio da se precizno<br />definiše mogući dalji trend geografskog<br />pomeranja staništa odabranih biljnih vrsta koji je u<br />korelaciji sa morfo-fiziološkim adaptivnim<br />odgovorom biljaka na promenu ekoloških uslova<br />životne sredine. Fotosintetička aktivnost tokom<br />vegetacione sezone bila je stabilna ili se<br />povećavala pri optimalnoj vlažnosti zemljišta. Na<br />lokalitetima Tara i Kopaonik količina<br />atmosferskih padavina nije igrala određujuću<br />ulogu u dinamici fotosintetičke asimilacije CO<sub>2</sub>.<br />Vlažnost zemljišta je na ovim lokalitetima bila<br />visoka i stabilna zbog dreniranja vode sa okolnih<br />brda. Registrovane razlike u dinamici fotosinteze<br />između ispitivanih vrsta povezane su sa različitim<br />životnim ciklusom listopadnih i četinarskih vrsta i<br />sa različitim fiziološkim adaptacionim<br />strategijama na promene faktora spoljašnje<br />sredine. Na dinamiku fotosintetičke asimilacije<br />CO<sub>2 </sub>signifikantno utiče prosečna temperatura<br />vazduha pre i tokom merenja, prosečna<br />osmonedeljna količina padavina pre merenja,<br />količina padavina na dan merenja, kao i<br />momentalna vlažnost zemljišta (MVZ). Rezultati<br />istraživanja ukazuju da će dejstvo klimatskih<br />promena biti više izraženo na šumskim<br />populacijama koje se nalaze na vršnim,<br />grebenskim lokalitetima većih nadmorskih visina,<br />ili na padinama planina. Sušni periodi tokom<br />vegetacione sezone, značajan su faktor pomeranja<br />šuma planinskih lokaliteta. Bukove šume su dobro<br />adaptirane na sušu i dobro podnose temperaturni<br />stres, međutim, dugi periodi sa oskudnim<br />padavinama izazivaju smanjenje asimilacije CO<sub>2</sub><br />što ograničava značaj šuma u ublažavanju<br />klimatskih promena.</p> / <p>During three vegetation seasons, physiological<br />parameters, such as photosynthesis, transpiration,<br />water use efficiency (WUE), as well as the parameters<br />of bioproduction of the beech (Fagus sylvatica L.),<br />spruce (Picea abies (L.) Kartsen) and fir (Abies alba<br />Mill.) forest populations have been investigated<br />depending on different altitude mountain. The<br />relationship between the photosynthesis (and<br />bioproduction) of plants and the slope of the mountain<br />is also specified according to ecological parameters<br />(water regime and temperature. The aim of this<br />research is to define physiological status of forest<br />mountain ecosystems in relation to the ecological<br />conditions and predict further trend of geographic shift<br />of the habitats, which is in correlation with the plant<br />morpho-physiological adaptation responses on<br />environmental changes. Photosynthetic activity<br />during vegetation season was stable or increased in<br />optimal level of soil moisture conditions. On the<br />localities of Tara and Kopaonik the quantity of<br />atmospheric precipitation did not play a determining<br />role in the dynamics of photosynthetic assimilation of<br />CO<sub>2</sub>. On these localities soil moisture was high and<br />stable as a result of water running off from<br />surrounding mountains. Detected differences in the<br />dynamics of photosynthesis of the tested species are<br />result of various lifecycles of deciduous and<br />coniferous trees and various physiological adaptation<br />strategies. The most influential effects on the<br />dynamics of the photosynthesis of the beech, spruce<br />and fir plants during the vegetation season were the<br />following abiotic factors: average air temperature<br />before measuring, temperature on the day of<br />measuring, eight-week amount of average<br />precipitation before measuring, amount of<br />precipitation on the day of measuring and soil<br />humidity. The analysis of the physiological parameters<br />of the beech populations of various mountain altitudes<br />show that even if beech is sensitive to draught it has<br />the physiological potential to keep its vitality by<br />efficient managing water. Effect of climatic changes<br />will be more expressed in forests that can be found on<br />high altitude mountain reefs and peaks. Beech forests<br />tolerate temperature and drought stress, but long<br />periods of poor precipitation cause the decrease of<br />CO<sub>2 </sub>assimilation which consequently decreases their<br />importance in the global reduction of atmospheric<br />CO<sub>2</sub>, i.e. limits their role in the moderation of climate<br />change.</p>
|
6 |
Regulation of nitrogen fixation in Klebsiella pneumoniae: NifL, one protein transducing two environmental signals to the nif-transcriptional activator NifA / Regulation der Stickstoffixieung in Klebsiella pneumoniae: NilL, ein Protein, das zwei Umweltsignale auf den nif-Transkriptionsaktivator NifA überträgtKlopprogge, Kai Gerhard 03 May 2001 (has links)
No description available.
|
7 |
Characterization of alternative NADH dehydrogenases in the respiratory chain of Toxoplasma gondii as a novel drug targets / Characterization of alternative NADH dehydrogenases in Toxoplasma gondii / Characterisierung der alternativen NADH Dehydrogenasen in der Atmungskette von Toxoplasma gondii - ein potentieller Angriffspunkt für Chemotherapeutika / Characterisierung der alternativen NADH Dehydrogenasen von Toxoplasma gondiiSaleh, Ahmad Mahmoud Hasan 01 November 2006 (has links)
No description available.
|
8 |
Wassernutzung und Wassermangelempfindlichkeit bei SommerweizenBräsemann, Ines 26 April 2018 (has links)
Wasserknappheit und Dürre sind große Herausforderungen für die Pflanzenproduktion auch in Teilen Mitteleuropas. Weizen aus dem mediterranen Klima sind wegen ihrer Anpassung an dortige Bedingungen eine potenzielle Quelle für eine verbesserte Dürreresistenz. In 2-faktoriellen Gefäßversuchen und 1-faktoriellen Feldversuchen wurden daher Wassernutzung, Biomasseproduktion, Kornertrag, Ertragsstruktur und Stickstoff-Nutzung von zwei mediterranen (Golia, Gönen) und 8 mitteleuropäischen Sommerweizensorten (Triticum aestivum L.) auf der Versuchsstation der Humboldt-Universität in Berlin-Dahlem untersucht. In den Gefäßversuchen (3 Jahre), unter Freilandbedingungen mit Regenschutz, sollte der Effekt von zwei Bewässerungsvarianten (optimale Bewässerung, restriktive Bewässerung nach Ährenschieben) erfasst und mögliche Sortenunterschiede identifiziert werden. Kornertrag und Biomasseproduktion zeigten starken genotypischen Einfluss und eine Reduktion durch das Wasserdefizit (2 Jahre). Die höchsten Kornerträge erreichten die mitteleuropäischen Sorten, gefolgt von Golia aus Italien mit höheren Erträgen als Gönen aus der Türkei. Bezüglich der Wassernutzungseffizienz (WNE) zeigten die Sorten des gemäßigten Klimas höhere Werte aufgrund von gleichzeitig höherer Evapotranspirationseffizienz (ETE) und Ernte-Index (EI). Auch in den Feldversuchen (2 Jahre) konnte für Biomasseproduktion und Kornertrag ein starker Sorteneinfluss gefunden werden, wobei wiederum die mitteleuropäischen Sorten höhere Erträge erzielten als Gönen. Dasselbe gilt für die WNE, wobei die Ursache in höherer ETE und EI bei den mitteleuropäischen Sorten liegt. Golia erreichte hinsichtlich Biomasse, Kornertrag, WNE und ETE das Niveau der mitteleuropäischen Sorten. Die frühe Trockenheit (2011) reduzierte den Kornertrag nur bei den Sorten aus dem mediterranen Raum verglichen mit der späten Trockenheit in 2010. Der Kornertrag der mitteleuropäischen Sorten war stabil zwischen den Jahren. / Water scarcity and drought are big challenges in agricultural production even in parts of Mid-Europe. Wheats from Mediterranean climate with their adaption to the local conditions may be considered a potential source of enhanced drought resistance. Therefore, in two-factorial pot experiments and one-factorial field experiments water use, biomass accumulation, grain yield, yield structure and nitrogen utilization of 2 Mediterranean (Golia, Gönen) and 8 mid-European spring wheat cultivars (Triticum aestivum L.) were studied on the experimental station of the Humboldt-University at Berlin. Pot experiments (3 years) were carried out under field site conditions with rain shelter to quantify effects of two watering regimes (well watered, water deficit after heading) and to identify possible differences between cultivars. Grain yield and biomass accumulation showed strong genotypic influence and were significantly reduces by water deficit in two years. Mid-European cultivars out yielded Mediterranean ones with Italian cultivar Golia showing higher grain yield than Turkish cultivar Gönen. Crude protein values were higher in Mediterranean cultivars with higher nitrogen amount in those from temperate climate. Clear differences between cultivars were found in water use efficiency (WUE) with higher values in mid-European cultivars due to simultaneously higher Evapotranspiration Efficiency (ETE) and Harvest Index (HI). In field experiments (2 years) biomass and grain yield were strongly influenced by cultivar with higher values in Mid-European cultivars than in Gönen. Similar results were found for WUE which was higher in cultivars from temperate climate because of higher ETE and HI. Italian cultivar Golia reached level of mid-European cultivars either in biomass and grain yield but also WUE and ETE. Early drought in 2011 lowered yield only in Mediterranean cultivars compared to terminal drought in 2010. Yield in cultivars from temperate climate was stable between years.
|
9 |
Evolutionary genetics and ecology of water use efficiency ([delta]¹³C) in Ipomopsis agregata and Arabidopsis thalianaKenney, Amanda Marie 31 January 2012 (has links)
My dissertation research investigates the genetic architecture and evolutionary significance of physiological variation in two wildflower species, Ipomopsis aggregata and Arabidopsis thaliana. In particular, my work focuses on water use efficiency (WUE), a critical physiological trait that dictates plant growth and performance in resource-limited environments. I used a combination of quantitative trait loci (QTL) mapping, field selection experiments, and classic quantitative genetics to investigate 1) the genetic architecture of water use efficiency and flowering time, 2) patterns of natural selection on water use efficiency, flowering time, and other ecological traits in I. aggregata, and 3) additive genetic variation, genetic correlations, and selection on water use efficiency, flowering time, and plasticity to drought in Arabidopsis thaliana.
Using an Ipomopsis aggregata genetic mapping population, I identified four QTL underlying WUE, three QTL-QTL epistatic interactions, and evidence for a possible QTL x cytoplasmic interaction affecting WUE. I found a similar genetic architecture underlying flowering time, with four main effect QTLs that all adjacently localized to the same linkage groups as WUE, and three QTL-QTL epistatic interactions, which occur between the same chromosome pairs as the WUE interactions. The combined main and interactive effects explain 35% and 40% of the phenotypic variation in WUE and flowering time, respectively. The adjacent localization suggests a possible role for the evolution of co-inheritance or, if the true QTL positions actually overlap, a possible role for pleiotropy underlying the phenotypic correlation between WUE and flowering time. Additionally, these results suggest epistasis is a significant factor affecting phenotypic variation in nature.
In a reciprocal transplant and water addition experiment, I demonstrated variable natural selection on WUE, flowering time, and nectar production in I. aggregata across elevation/habitat and differential water availability. At low elevation in the water addition treatment, natural selection favors early flowering and greater nectar sugar concentration, while dry conditions favor high WUE and early flowering time. At high elevation, where the growing season is shorter and drier, selection favors early flowering regardless of water addition. These results suggest natural selection on ecophysiological and floral traits varies with resource availability (e.g. water availability and pollinator visitation).
Using data from a glasshouse experiment involving a global panel of accessions of Arabidopsis thaliana, I demonstrated strong positive genetic correlation between WUE and flowering time, as well as selection for low WUE and early flowering under experimental season-ending drought. Finally, I found significant genetic variation in plasticity as well as selection favoring greater WUE plasticity under drought, indicating plasticity to drought is adaptive in A. thaliana. / text
|
10 |
Investigation of glycolysis in Bacillus subtilis / Untersuchung der Glykolyse in Bacillus subtilisPietack, Nico 29 April 2010 (has links)
No description available.
|
Page generated in 0.0168 seconds