Les pectines de la paroi cellulaire végétale sont impliquées dans un grand nombre de processus physiologiques. Toutefois, la fonction exacte des pectines - au niveau structurel comme dans le contexte de la biologie et du développement cellulaire - est toujours un sujet de controverses. D’autre part, des observations soulèvent la question du rôle des fragments pectiques dans le contrôle de la floraison (Marfà et al., 1991) et les changements de communication intercellulaire observés au sein du méristème apical lors de la transition florale (Ormenese et al., 2000, 2002) impliquent des modifications biochimiques de la structure de la paroi cellulaire. Comme décrit par Liners et al. (1994), nous avons étudié par immunocytochimie (microscopie électronique et confocale) la nature, la localisation et le contenu en pectines dans des méristèmes de plantes de Sinapis en conditions végétatives ainsi que lors de la transition florale. Une diminution importante mais transitoire du contenu en homogalacturonanes de la paroi cellulaire est observée au cours des premières heures de la transition florale. Cette diminution du contenu en pectines doit être la conséquence d’une libération d’enzymes pectolytiques dont les pectine méthylestérases (PME) au niveau du méristème. Afin d’étudier l’expression des PME dans le méristème lors de la transition florale, nous avons produit et caractérisé un polysérum contre un zone extrêmement conservée des gènes de PME de S. alba./Immunocytochemical study of pectins and pectin modifications at floral transition in meristems of Sinapis alba L. By Stéphanie Sobry Abstract : Plant cell wall pectins are implicated in a large number of physiological processes. However, the exact functions of pectins – at a structural level as well as in the context of cell biology and development - are still debatable. On the other hand, observations raise the question as to whether pectic fragments are involved in the in vivo control of flowering (Marfà et al., 1991) and communication changes between the cells of the apical meristem in floral transition (Ormenese et al., 2000, 2002) imply biochemical modifications of the cell wall structure. Using immunocytochemistry (electron and confocal as described in Liners et al. (1994), we studied the nature, localization and content of pectins in meristems of Sinapis in vegetative plants and at floral transition. A marked but transient decrease of the homopolygalacturonic content of the cell wall occurs in the first hours of the transition to flowering. This pectin content decrease must be due to the release of pectolytic enzymes like pectin methylesterase (PME) in the meristem. To study PME expression in the meristem at floral transition, we raised and characterized polyclonal antibodies to highly conserved sequences of S. alba PME genes.

Master thesis is focused on the monitoring and evaluation of the phytotoxicity of lea-chate of municipal solid waste landfill from Bukov. Introduction includes statistical data, waste management methods, legislation and terminology of waste management. Further, the thesis contains a description of the landfilling process with a focus on water monitoring, description of phytotoxicity tests and basic information about Bukov municipal solid waste landfill. Experiment is focused on phytotoxicity tests of leachate water from a given landfill. The final part contains the evaluation of the results and their in-terpretation.

Thesis on Phytotocity leachate from landfills Štěpánovice deals with basic concepts and legislation related to municipal waste and landfill in theoretical part. There are also procedures in waste management, their hierarchy, and statistical evaluation of the amount of multicipan waste. Another part of a literature search is aimed at monitoring water, general description of the storage process and general description of phytotoxicity. The practical part describes the process of solid municipal waste landfill Štěpánovice, its natural circumstances, locations and the integration in the territory. There is also described and discussed experiment which was realized by semi-chronic toxicity leachate method with white mustard (Sinapis alba L.). Followed by evaluation of the results and their interpretation in the current comparison of results with other writers.

The relative amount of viral RNA of two comoviruses (RaMV and TuRSV) in different parts of plant during infection was determined. The two viruses were compared according to their ability to spread and multiply in plants.

The diploma thesis “The assessment of the phytotoxicity of sludge from selected sewage treatment plants“ deals with the current situation of the sludge treatment and disposal and the assessment of phytotoxicity of sewage treatment sludge. The sewage treatment sludge comes into existence during the process of sewage treatment. Nowadays is sludge landfilling from the point of view of nature protection and according to the legislation on the last place in a way of handling. Additionally, the thesis pays attention to the legislation related to the sewage treatment sludge and also statistical data concerning the production and the way of handling of the sewage treatment sludge. The practical part of the diploma thesis is focused on the description of two sewage treatment plants, namely Třebíč and Náměšť nad Oslavou. Subsequently were made several laboratory experiments with the sewage treatment sludge samples from the mentioned sewage treatment plants. At the sewage treatment sludge samples were assessed the phytotoxicity level by the testing set Phytotoxkit. Specifically was determined an inhibitive/stimulative effect on the growth of the root. The testing plant was a white mustard (Sinapis alba L.).

Onset of flowering is a major transition in the plant life cycle and is controlled by environmental factors including photoperiod, light quality and temperature. Prevalence of controlling factors depends on species, hence physiological models were selected for their strong requirement for one or another environmental cue. Among Brassicaceae, Sinapis alba was intensively studied for its strong response to photoperiod while molecular-genetic analyses of Arabidopsis thaliana disclosed complex interactions between pathways inducing flowering in response to photoperiod and other environmental cues, such as vernalization. We were therefore interested in studying the vernalization process in S. alba and its interactions with the previously characterized floral response to long days (LDs). Two-week old seedlings grown in non-inductive short days (SDs) were vernalized at 7°C for increasing durations and a strong promotive effect of vernalization was observed. In contrast to the common view of vernalization as a preliminary step bringing the competence to flower, we observed that vernalization had a direct inductive effect on flowering: floral buds were initiated during cold-exposure. Floral integrator genes SaMADSA (homologous to SUPPRESSOR OF OVEREXPRESSION OF CO 1) and SaLEAFY were up-regulated in the shoot apex after 3-4 weeks of vernalization. To monitor the vernalization process at the molecular level, we isolated SaFLC which, based on sequence analysis, expression patterns and complementation test, appeared as orthologous to FLOWERING LOCUS C. Down-regulation of SaFLC by vernalization was fast since transcript level was already very low after one week of vernalization, but stability of the repression required longer exposure to cold. To test the physiological significance of these observations, we studied the floral response to 16-h LDs after unstable and stable repression of SaFLC. We observed that one week of vernalization which was sufficient for SaFLC repression but not for maintenance of the silenced state - increased the flowering response of S. alba to LDs when the LDs just followed the cold treatment. This effect was lost after two weeks post-vernalization. In contrast, the promotive effect of longer vernalization on flowering response to LDs was maintained post-vernalization. These results suggested that vernalization not only works when plants experience long exposure to cold in winter: short cold periods might stimulate flowering of LD-plants if occurring when photoperiod is increasing, i.e. in spring.