The aim of the diploma thesis was to find out the termination date of endogenous dormancy of bud flowers within the selected set of apricot varieties and simultaneously keep track of the development of various phases of microsporogenenesis. The last goal was to capture the phenological indicators of flowering and fruit development. The experimental part describes material and methodology tested on the peach varieties at Horticultural Faculty in Lednice in a two-year experiment during 2013-2014. The temperature curve was significantly different in both years. Year 2013 was characterized by gradual and lengthty progression of low temperatures, and by late termination of endogenous dormancy. Year 2014 was entirely unlike the previous one in its rapid progression of above-average temperatures and dynamic emersion of varieties from dormancy. After evaluating the results the varieties were divided into three groups with short, medium and long period preceding the termination of dormancy. The results of the observation of microsporogenesis phases shows that development of each phase is not uniform in all varieties of monitored peaches. The pollen grains development rate is greatly influenced by the temperature curve. Varieties with late termination of dormancy and slow development of microsporogenesis phases are less susceptible to impairment of the flower buds by late spring frosts.

Microtubers were obtained from potato plants (Solanum tuberosum L.) cultured in vitro, they were used in following experiments. The impact of growth regulators (FLD, AgNO3, BA, ABA) was monitored in length of dormancy. The content of ABA in the budding tubers and the content of endogenous CK (BA, IP, DHZ, DHZR, Z) was determined during the dormancy as well. Production of ACC, ethylene, O2, CO2 and ethane was determined by gas chromatography. Variants containing FLD, AgNO3 and BA had a significant impact in the shortening of dormancy and stimulation the growth of buds microtubers. When they were used the occurrence of budding tubers was increased by 30-40 % over the control. Variant of ABA inhibited the growth of buds. ABA content correlated with the process of dormancy and the occurrence of budding tubers. The highest content of ABA was in variant with freshly collected dormant tubers. Concentration of various CK was dependent on the type of CK and monitored variant. Generally, It was slightly increased with occurrence of budding tubers.

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The theme of this thesis monitoring of differences between crop yield potatoes from germinated and ungerminated planting. The theoretical part summerizes the basic information about potatoes and it pays attention to pregermention of potato plantig.

As achieving higher frost resistance is one of the apricot breeding goals in the Czech Republic, it is important to obtain a deeper understanding of the genetic background of the exit from endogenous dormancy for apricot flower buds. The reason is that frost resistance of flower buds is significantly reduced after exit from endogenous dormancy. The aim of this work was to contribute to the understanding of the process of exit of various plant tissues from dormancy, as the problem is very complex and containing a number of physiological processes that are controlled by the function and regulation of many various substances and corresponding genes. The time of exit of flower buds from endogenous dormancy was established by counting of flowering buds on sampled twigs after their transport to laboratory conditions. Furthermore, the production of ethylene, ethane, and CO2 was monitored for sampled twigs with flower and leaf buds. Other physiological parameters monitored during the course of this study were the level of abscisic acid in flower buds and their weigh during the sampling close to the period of exit from endogenous dormancy. An analysis of transcriptome using the cDNA-AFLP method was carried out on four apricot variants ('Sundrop', SEO, 'Vestra' a 'Betinka') to achieve a deeper understanding of the genetic background of exit of flower buds from endogenous dormancy. The transcription profiles obtained from this experiment were evaluated for changes in the expression profiles and fragments of genes with modified expression during the monitored period were sequenced identified. Obtained sequences were compared with sequences in electronic databases (NCBI and TIGR). The results of this comparison led to the identification of a number of the sequenced genes. The results of this study confirmed the suitability of use of the cDNA-AFLP method for the identification of gene candidates and getting a preliminary picture of the main molecular mechanisms taking place during the time of exit of flower buds from endogenous dormancy. The suitability of the used procedure was confirmed by the match between the genes identified from the sequencing and genes already described in the literature as being linked to the exit of plants from endogenous dormancy (e.g. gene coding for acquaporin, GTP-binding proteins, elongation factor 1 alpha, ubiquitin, and xyloglucan endotransglycosylase hydrolase). Measurements of concentration of selected substances during exit from endogenous dormancy do not allow definite conclusions about their influence on this process. On the other hand were identified several genes that might be candidates for markers identifying the output timing of endogenous dormancy of buds and provide a good starting point for further scientific research in this field.

Dissertation work deals with the evaluation of the selected characters of promising peach varieties grown in the genepool collection and pilot testing block. The evaluation took place between year 2011 to 2013. The work can be divided into three thematical units. The first part deals with the health condition, specifically monitoring of the occurrence of European stone fruit yellows phytoplasma (ESFY) and the plum pox virus (PPV). The second part focuses on the physiological events occurring in flower buds (dormancy, microsporogenesis, frost resistance) and the third unit deals with pomological characteristics of varieties and the economic evaluation of varieties which are already introduced in the commercial cultivation. In the literature section the origin and the spread, world production of peaches and the current situation in the Czech Republic are descibed and a chapter about peach breeding is included as well. Further, chapters characterizing dormancy, microsporogenesis and frost hardiness are described in the work. Literature section also includes content substances and health-promoting substances in peach fruit. The last chapter describes the diseases causing economically significant losses in peaches. In the experimental part the incidence and symptoms of phytoplasma ESFY and synergism between PPV and ESFY was evaluated. The effect of the PPV infection on content of the total polyphenols and the antioxidant activity of fruits was investigated. Further, the termination of dormancy, microsporogenesis and frost resistance of flower buds was evaluated. Significant part of work was the pomological evaluation of selected varieties from genepool collection and evaluation of varieties in pilot testing block conditions. The results show that in peach orchards trees infected by phytoplasma ESFY show various symptoms of the disease which depend on host genotype. Synergism between Plum pox virus (PPV) and European stone fruit yellows phytoplasma (ESFY) has not been confirmed. PPV infection results in increased amount of the antioxidant activity and total polyphenols in peach fruits.Varieties can be divided into 3 groups by the term of termination of endogenous dormancy, paticulary, varieties with early termination, varieties with medium termination and varieties with late termination of dormancy. Evaluated varieties differ, either, in duration and date of occurence of phases of microsporogenesis. The process of dormancy and microsporogenesis of individual varieties is different and is influenced by the weather conditions of the year. There are differences in frost resistance between peach varieties. The highest degree of frost hardiness was set by the 'Lesiberian'. Studied peach varieties show differences in pomological, biological and economic characters. From the evaluated group of varieties the promising are 'Venus', 'Fantasia', 'Fidelia', 'Neve' and 'W 14', where the highest assessment had the variety 'Venus'. Based on evaluation of peach varieties grown in commercial orchards the best variety was 'Symphonie', which achieved consistently high yields and is characterized by good health. 'Fidelia' and 'Orion' were chosen as a mediumly suitable varieties for commercial orchards.

L’agent pathogène responsable de la tuberculose, Mycobacterium tuberculosis, utilise principalement les lipides comme source d’énergie lors du processus infectieux. Cela suggère que les enzymes lipolytiques (ELs) sont des facteurs d’une importance cruciale, qui jouent un rôle essentiel pour la survie et la persistance du bacille au sein des granulomes tuberculeux. Dans ce contexte, nous nous sommes intéressés au rôle physiologique de la protéine LipY (Rv3097c), une TAG-hydrolase apparentée à la lipase Hormono-sensible humaine. En utilisant un modèle expérimental de « foamy » macrophages, nous avons démontré que cette protéine sécrétée par le système de sécrétion ESX-5 était responsable de l’hydrolyse des triacylglycerols (TAG) de l’hôte dans la lumière phagosomale. Dans une seconde étude, nous avons développé un modèle expérimental robuste et réversible basé sur la biodisponibilité en azote et en carbone, deux facteurs essentiels qui gouvernent la formation et l’hydrolyse de TAG sous la forme d’inclusions lipidiques intracytoplasmiques (ILI) chez les mycobactéries. La simplicité d’utilisation de ce modèle s’avère être un excellent système biologique permettant d’étudier les propriétés phénotypiques des bacilles riches en ILI. L’ensemble des résultats obtenus au cours de ces travaux de thèse confirme que certaines ELs sont directement impliquées dans la virulence et/ou la survie des mycobactéries pathogènes. De plus, une très grande partie de ce travail ouvre de nouvelles perspectives sur la caractérisation et l’inhibition d’acteurs protéiques essentiels au métabolisme des lipides in vivo, offrant ainsi de nouvelles opportunités pour lutter contre M. tuberculosis. / Mycobacterium tuberculosis, the pathogenic agent responsible for tuberculosis (TB), mainly uses lipids as a source of energy during the infectious process. This suggests that lipolytic enzymes (LEs) are crucial metabolic agents that play a critical role in the survival and persistence of the bacillus within TB granulomas. In this context, we investigated the physiological role of the LipY protein (Rv3097c), a TAG-hydrolase related to the human Hormono-sensitive lipase. Using an experimental model of "foamy" macrophages, we demonstrated that this protein which is secreted by the ESX-5 secretion system, was responsible for the hydrolysis of host-derived triacylglycerols (TAGs) within the phagosomal compartment. In a second study, we developed a robust and reversible experimental model based on the bioavailability of nitrogen and carbon, two essential factors that govern the formation and hydrolysis of TAGs in the form of intracytoplasmic lipid inclusions (ILI) in mycobacteria. The simplicity of this model proves to be an excellent biological system for studying the phenotypic properties of ILI-rich bacilli. All the results obtained during this thesis confirm that some LEs are directly involved in the virulence and/or survival processes of pathogenic mycobacteria. In addition, we truly believe that this work opens up new perspectives on the characterization and inhibition of protein, that are essential actors for lipid metabolism in vivo, thus offering new opportunities to better control M. tuberculosis.

Peut être plus encore que dans d'autres secteurs de production végétale, en horticulture les contraintes économiques imposent une technicité croissante. L'artificialisation des productions de plants de fraisiers a commencé depuis longtemps. L'empirisme a permis de mettre au point des pratiques qui ont longtemps suffi. Mais, cette artificialisation demande de plus en plus une maîtrise raisonnée qui doit reposer sur des connaissances précises de l'écophysiologie des plants. D'autre part, des recherches ont permis de définir un test de capacité de croissance des bourgeons, inspiré de ceux faits sur les bourgeons des arbres, et nous l'avons mis en oeuvre comme référence. Cependant, en particulier au niveau de l'intérêt pour les professionnels, ce test implique des méthodes encore trop lourdes. D'autres marqueurs plus faciles à mesurer semblaient des candidats valables, mais seules des études préliminaires ont été faites.C'est le cas du flux de chaleur métabolique (Q) et du flux de respiration (RCO2) que nous avons testé en mesure immédiate et après acclimatation des plants à 20°C. Nos résultats indiquent que Q et RCO2 en mesure immédiate ne peuvent constituer de bons marqueurs de capacité de croissance, car leurs valeurs sont fortement corrélées aux températures moyennes subies par les plants dans les quelques jours précédant la mesure. En revanche, le différentiel obtenu entre mesure immédiate et mesure réalisée après acclimatation pendant 48 h à 20° C est potentiellement un marqueur intéressant, d'obtention beaucuop plus rapide que les résultats des tests classiques. Il faudra cependant optimiser les conditions de réalisation de l'acclimatation et des mesures microcalorimétriques et augmenter sensiblement le nombre de répétitions des mesures. L'utilisation du paramètre humidité pondérale, dont la dynamique d'évolution est très proche de celles de Q et RCO2, comme substitutif à ces paramètres peut constituer un autre outil intéressant les producteurs de plants

La Sucrose non-fermenting Related Kinase (SnRK1), en interaction avec ses deux sous unités : b et g (SNF4), est un important régulateur du métabolisme et des réponses aux stress chez les plantes. Le but de cette thèse est d'étudier le rôle de MtSNF4b, une sous unité g spécifique des graines de Medicago truncatula, pendant l'imbibition en relation avec la germination. Une analyse physiologique de la germination des graines RNAi MtSNF4b au cours de la post maturation à sec montre que les graines n'exprimant pas MtSNF4b perdent leur dormance plus rapidement que les graines de type sauvage. Une analyse transcriptomique comparative entre des embryons RNAi MtSNF4b et types sauvages montre que la plupart des gènes sont réprimés dans les graines RNAi MtSNF4b et sont liés au stress biotiques. Ces gènes codent des pathogenesis related protéines de type PR-10, des chitinases ou des facteurs de transcription de type WRKY et des enzymes impliquées dans le métabolisme secondaire, notamment les voies métaboliques des phénylpropanoïdes et des isoflavonoïdes pour la biosynthèse de la médicarpine. Cependant, aucune différence dans la sensibilité des semences imbibées de type sauvage et RNAi MtSNF4b à deux souches de Xanthomonas par l'analyse de dynamiques de tailles des populations bactériennes n'a pu être mise en évidence. Des résultats préliminaires d'une étude de double hybride mettent en évidence plusieurs candidats potentiellement impliqués dans la régulation de ces gènes. La protéine MtSNF4b semble connecter la post maturation à sec avec les mécanismes de défenses dans les graines dormantes de Medicago truncatula.