Experimental studies of the flowering of Arabidopsis Thaliana have shown that a large complex gene regulatory network (GRN) is responsible for its regulation. This process has recently been modelled with deterministic differential equations by considering the interactions between gene activators and inhibitors [Valentim et al., 2015, van Mourik et al., 2010]. However, due to the complexity of the models, the properties of the network and the roles of the individual genes cannot be deduced from the numerical solution the published work offers. In this study, deterministic and stochastic dynamic models of Arabidopsis flowering GRN are considered by following the deterministic delayed model introduced in [Valentim et al., 2015]. A stable solution of this model is sought by its linearisation, which contributes to further investigation of the role of the individual genes to the flowering. By decoupling some concentrations, the system has been reduced to emphasise the role played by the transcription factor Suppressor of Overexpression of Constants1 (SOC1) and the important floral meristem identity genes, Leafy (LFY) and Apetala1 (AP1). Two-dimensional motifs, based on the dynamics of LFY and AP1, are obtained from the reduced network and parameter ranges ensuring flowering are determined. Their stability analysis shows that LFY and AP1 are regulating each other for flowering, matching experimental findings (see e.g. [Bl ́azquez et al., 2001, Welch et al., 2004, Yeap et al., 2014]). Moreover, the role of noise is studied by introducing and investigating two types of stochastic elements into the motifs. New suffient conditions of mean square stability and their domain are obtained analytically for the stochastic models using Lyapunov stability theory. Numerical solutions are obtained by using Euler-Maruyama method and Ito stochastic formula. We demonstrate that the stochastic motifs of Arabidopsis flowering time can capture the essential behaviour of the full system and that stochastic effects can change the behaviour of the stability region through a stability switch. Furthermore, the problem of designing an observer and a controller, in which FT is seen as a control input, is considered in the objective of ensuring flowering conditions are met. This study thus contributes to a better understanding of the role of LFY and AP1 in Arabidopsis flowering.

Seed development in Arabidopsis thaliana, has been studied at several levels. However, little has been done to study the role of sugar metabolism genes in seed pod development in this species. As the fertilized egg progresses to a mature seed, the sugars composition during different stages of the developing changes. These changes are related to metabolic processes in the developing seeds, but also to the activity of sucrose- converting and transporting genes, active at the interphase between the maternal tissue and the endosperm. Sucrose synthase (SUS) is one of these genes; it catalyses the reversible reaction of sucrose breakdown in the presence of UDP to form fructose and UDP-glucose. In this study we looked at glucose, fructose and sucrose concentration at different time points during seed pod development. These changes in sugar concentrations were analysed in both Colombia wild type and WS (Wassilewskija) ecotypes. By comparison of the sugar composition of these ecotypes, and linking these data with phenotypic observations in both ecotypes during development, we are able to comment on the possible role of sugars in seed pod development. Also, the sugar composition of wild type seed pods were compared with those of Atsus mutant seed pods, and possible effects sucrose synthase mutations on the phenotype of the developing Arabidopsis thaliana seeds were analysed. The effect of sucrose synthase knockouts in developing seed pods were studied by comparing biochemical and phenotypic characteristics data of the Atsus mutants within Colombia wild type plants. Salk line plants were screened to identify plants carrying a homozygous insertion for T-DNA in five of the sucrose synthase genes. The developing seed pods of each of the homozygous mutants were characterized biochemically via High-Performance Anion-Exchange Chromatography (HPAEC). Furthermore, seed weight, number of seed per pod, germination rate and the morphological development of the embryo were closely analysed. The study found out that there were some biochemical effects of Atsus knockout mutants, and some phenotypic effects of Atsus knockout mutants on the developing seed pods. However, in general the effects were not as pronounced as those that were seen in maize seed, pea seed and potato tuber as a result of sucrose synthase knockout. The general pattern of glucose, fructose and sucrose were similar to the Colombia wild type, although in mature seed pods the sucrose levels in Atsus1, Atsus2, Atsus3 and Atsus6 were slightly, but significantly lower than in the Colombia wild type.

The Wealden ghyll woodlands are associated with unique plant assemblages that include nationally rare bryophyte species with oceanic affiliations. The identification and monitoring of this type of 'priority' habitat, recognised as important in terms of regional and national biodiversity, is a central facet of the UK Biodiversity Action Plan (UKBAP). Despite the acknowledged importance of ghyll woodlands for non-vascular plant species, previous studies attempting to examine and characterise the ghyll woodlands have neglected to include these bryophyte communities. This research identifies and characterises the Wealden ghyll woodlands through an examination of the spatial and temporal distributions of bryophyte and flowering plant species. The research also seeks to provide baseline data against which biodiversity levels can monitored. In order to identify and contextualise the importance of ghyll woodland in terms of regional biodiversity, survey data was collected from other types of ancient woodland throughout the region for comparative analysis. The study involved the collection of species and environmental data from a total of 1440 random quad rats from 60 survey sites situated throughout the Weald, as well as the use of archive survey data collected during two 20 year periods (1951-1970 and 1976-1995). A number of statistical approaches including general linear modelling, ANOSIM, MannWhitney U and Spearman rank correlation analysis were used to identify the environmental correlates of spatial and temporal changes in species distributions. Spatial analysis indicated that ghyll woodland is restricted to the stream valleys themselves which were significantly richer in bryophyte and flowering plant species than the surrounding woodlands. NVC classifications assigned to the ghylls indicated the presence of 'oceanic' plant communities that are associated with damp, humid microclimatic conditions. A number of authors have explained the presence of oceanic bryophytes within the ghylls as being the result of a damp, humid microclimate present within the stream valleys. However, the study found no significant differences between climatic conditions within the ghyll valleys and those in the surrounding ancient woodlands. ANOSIM analysis indicated that community composition was influenced by site substrate, with clay and sandstone ghyll woodlands containing significantly different plant communities. Chi-squared analysis identified a temporal increase in the ratio of oceanic bryophytes and ancient woodland indicator flowering plant species during the study period. Analysis of Ellenberg indicator values indicated a move towards more shadetolerant plant communities within the ghyll woodlands. The patchily distributed ghyll woodlands were examined for signs of habitat fragmentation through genetic analysis of the bryophyte Conocephalum conicum (Great Scented Liverwort) using the random amplification polymorphic DNA technique (RAPD). Wright's fixation index (FST) and Nei 's coefficient of gene variation (GST) both indicated a loss of genetic diversity characteristic of genetic isolation. A Mantel test based on Nei 's genetic distance values indicated that the genetic isolation observed was not correlated with the geographical distance between populations. The study indicated that temporal changes are occurring in the composition of ghyll woodland plant communities and that bryophyte populations are displaying symptoms of genetic isolation. The study illustrates the importance of some form of monitoring program if the biodiversity value of these sites is to be maintained.

V. faba fixes nitrogen effectively (Richards & Soper, 1979), however nitrogen fixation is reportedly energetically expensive and water deficit sensitive. Research was designed to determine whether medium nitrogen applications would result in increased productivities in V. faba, particularly during water deficits. Non-nodulated and nodulated V. faba were subjected to gradual water deficit imposition, and were supplied with a variety of medium nitrogen nutrition. Nitrogen fixing V. faba exhibited greater productivities than V. faba which were supplied with low medium nitrate concentrations (0.8 roM N), even during water deficits. Plant performance parameters (growth; net photosynthesis; nitrogen assimilatory enzyme activities; osmotic adjustment) were greater in nodulated than in non-nodulated 'no nitrate' supplied V. faba throughout water deficits, inferring water deficit tolerance for nitrogen fixation. However significantly greater plant performance paramaters were exhibited in V. faba when supplied with increasingly concentrated medium nitrogen nutrition (> 0.8 roM N) than when reliant on nitrogen fixation. In contrast to the bulk of previous literature, NR activities were maintained in V. faba until water deficits became severe, inferring a role for nitrate assimilation in nitrogenous osmotica production. Medium ammonia additions resulted in the exhibition of significantly increased root biomasses; cumulative leaf areas (important for a green manure crop); heights; and nitrogen assimilation in V. faba throughout water deficits, and accordingly in increased osmotic adjustment (including compatible solute accumulation), protein concentrations and vegetative yields. Greater plant productivities in v. faba when supplied with medium ammonia additions were attributed in part to lower associated assimilatory costs for ammonia than nitrate nutrition (Raven, 1992). Results indicated increased metabolism as opposed to storage of medium ammonia, and therefore potentially alleviated 'sink size' feedback inhibition of photosynthesis and nitrogen metabolism in V. faba when supplied with medium ammonia additions. Furthermore ammonia supplied V. faba may have been predisposed towards water deficit tolerance. In summary V. faba exhibited significantly greater nitrogen assimilation; osmotic adjustment; net photosynthesis; and growth when supplied with increasingly concentrated medium nitrogen nutrition (and particularly with medium ammonia additions) than when reliant on nitrogen fixation, both during periods of adequate irrigation and during water deficits.

This report studies the possibility of integrating Transport Management Services (TMS) in a low-cost platform called Communicator 200 (C200). The platform is developed by Scania and is a black box that manages vehicle data, positioning, and wireless communication. The C200’s main purpose is to connect a hauler’s vehicles to their office system via wireless links and Internet. The thesis describes the design and implements a prototype of a service called Messaging that is used to send text messages between truck and office. The prototype is evaluated and tested with different web browsers in various hand-held terminals with different screen sizes. The main conclusion is that it is technically possible to integrate TMS in the C200 without altering the platform architecture too much. / Denna rapport undersöker möjligheten att integrera transportledningstjänster i en billig platform kallad Communicator 200 (C200). Platformen är utvecklad av Scania och är en svart låda som hanterar fordonsdata, positionering och trådlös kommunikation. C200 huvudsyfte är att sammankoppla ett åkeris fordon med deras kontorssystem via trådlösa förbindelser och Internet. Rapporten beskriver designen och implementerar en prototyp av en tjänst kallad Messaging som används för att skicka textmeddelanden mellan lastbil och kontor. Prototypen utvärderas och testas mot webbläsare i olika handhållna terminaler med olika skärmstorlekar. Huvudslutsatsen är att det är möjligt att integrera transportledningstjänster i C200 utan att ändra plattformens arkitektur alltför mycket.