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Úloha brassinosteroidů v odpovědi různých genotypů kukuřice na změny v zásobování vodou.
Trubanová, Nina ; Rothová, Olga (advisor) ; Hnilička, František (referee)
Brassinosteroids (BRs) have been recognized to alleviate damages caused by drought stress and to enhance tolerance to water deficit. Soaking of maize kernels before the sowing in solution with different 24-epibrassinolide concentrations (especially the 10-8 M) had a positive effect on growth of plants before and after the stress period, although it did not affected relative water content and photosynthetic parameters. After the recovery under optimal conditions there were no differences among the treatments. When compared to spraying, soaking of maize kernels was not proved to have any advantages, though its positive effect on plants germination under water deficit conditions could be possible. Based on the results of the second season experiment it is not possible to deduce the role of exogenous BRs application (spraying with 24-epibrassinolide) or endogenous BRs biosynthesis (spraying with biosynthesis inhibitor - brassinazole) in maize plants subjected to water deficit. However, decrease in relative water content in contrast to chlorophylls content increase during the days following after drought stress onset in both cultivars (contrastive in drought sensitivity) challenges for further investigation of this problem. Understanding the role of BRs in plant drought tolerance and resistance is...
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Polyploidy with specific view to paleopolyploidy and its detection
Kotz, Matěj ; Král, Jiří (advisor) ; Rothová, Olga (referee)
Polyploidy is a significant phenomenon in the evolution of eucaryotic organisms. It has been a subject of interest of biologists for decades and it has been studied particularly largely in plants, where it most often occurs. This thesis handles occurrence of poylploidy in organims and a special emphasis is laid on old polyploidization events occurrence of polyploidy in animal taxa. Furthermore, the types of polyploidy and obstacles are discussed here, that a polyploid organism has to tackle to stabilize its genome. That also includes the need to ensure the correct chromosome segregation in a meiotic division. A special case of polyploidy is paleopolyploidy (sometimes refered to as "ancient polyploidy" in English), which is an evolutionary old polyploidization event, that is followed by the process of diploidization. This process is characterized besides others by a large number of structural changes in chromosomes and a loss of some DNA sequences and a gradual transition of the polyploid genome to the cytologically diploid state. Because of these changes, it is difficult to detect a paleopolyploidy and the main part of this thesis is dedicated to this problem, in which the main approaches that might lead to its detection are discussed. Key words: polyploidy, animal, plant, meiosis, paleopolyploidy,...
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Mutations in brassinosteroid biosynthetic genes and their effects on plant phenotype
Frimlová, Klára ; Rothová, Olga (advisor) ; Mašková, Petra (referee)
Brassinosteroids are important group of phytohormones, whose presence affects anatomy, morphology and development of plants. They occur in all vegetative and mainly generative organs. Brassinosteroids are biosynthesized via two main paths named early C-6 oxidation pathway and late C- 6 oxidation pathway. Brassinosteroid biosynthesis is catalyzed by enzymes from the group of cytochrome P450. Gene mutations - which affect brassinosteroid biosynthesis - have been studied especially in Arabidopsis thaliana L., Pisum sativum L., Solanum lycopersicum L. and Oryza sativa L. Mutations lead to changes in the composition and amount of brassinosteroids in plants. The reduced content of brassinosteroids is manifested by typical phenotype that includes reduced growth, reduced size of plant organs, and dark green leaves in mutant plants. The mutant phenotype can be reversed by exogenous application of brassinosteroids, which is nevertheless dependent on the concentration of the brassinosteroids used. Higher concentrations of brassinosteroids cause mostly inhibition of root elongation. Keywords: brassinosteroids, biosynthesis, mutant, phenotype
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Role of brassinosteroids in plant response to drought stress
Trubanová, Nina ; Rothová, Olga (advisor) ; Urban, Milan (referee)
Brassinosteroids are steroid phytohormones with a wide range of effects. They improve survivance of plants exposed to drought stress, increase their resistence and yield therethrough. They regulate the response of plants directly (via synthesis of metabolits) and/or indirectly (via the induction of antioxidant compounds and enzymes), often in interaction with other phytohormones. Experiments studying influence of brassinosteroids on response of plants stressed with water deficit differ in several parameters. Their correct interpretation is complicated conseguently.
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Karyotype evolution of velvet spiders (Araneae: Eresidae)
Forman, Martin ; Král, Jiří (advisor) ; Rothová, Olga (referee)
Presented study is aimed to determine basic trends of karyotype evolution in velvet spiders (Eresidae; Araneae). Eresids are burrowing spiders; they includes also some social species. Karyotypes of 16 species of the family Eresidae as well as 2 species of the other families of the superfamily Eresoidea, Hersiliidae and Oecobiidae, are presented. Furthermore, DNA content and base proportion was determined in 14 species. In two species, DNA content of sex chromosomes was also measured. Obtained results revealed considerable variability of diploid numbers, and sex chromosomes systems in eresids. Obtained karyotype data allow to divide eresids into four groups. Karyotypes of the genera Gandanameno, Dresserus and S. lineatus are close to proposed ancestral karyotype of entelegynae spiders and they show the ancestral state of karyotype in velvet spiders. Karyotypes of S. lineatus and E. annulipes differ substantially from other representatives of the genera Stegodyphus and Eresus which indicates paraphyly of these genera. Karyotypes of basal forms are formed by acrocentric chromosomes. Further evolution of eresid karyotypes included considerable reduction of diploid numbers as well as changes of chromosome morphology. Social species of the genus Stegodyphus show tendency to reduce diploid numbers by...
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Response of primary photosynthetic processes in C3 and C4 monocotyledonous plants to steroids aplication
Frimlová, Klára ; Rothová, Olga (advisor) ; Mocová, Klára Anna (referee)
Brassinosteroids and ecdysteroid are naturally occuring chemical compounds in plants. The aim of this study was to show whether the application of exogenous steroids such as brassinosteroids (24-epibrassinolide, 28-homobrassinolide, 24-epicastasterone) and ecdysteroid (20-hydroxyecdysone) can affect the morphological parameters and primary photosyntetic processes of selected monocotyledons that was barley, wheat, maize and sorghum. Non-destructive method for measuring of fast kinetics of chlorophyll fluorescence in investigated plants was used. Analysis of primary photosynthetic processes was realized in five time periods from the application of exogenous steroids on the two different old leaves. The response to the treatment by exogenous steroid was different species by plant species. One week after the application of exogenous steroids plants showed differences in their morphological parameters but most of them were not signifficant. The most steroid-sensitive plant was wheat morphological parameters of were significantly different from untreated control plants. No change in maximum quantum yield of photosystem II to the application of exogenous steroid in plants of Sorghum bicolor L. was detected. In the other examined plant species changes in photosynthesis parameters were detected which...
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Gene expression of specific parts of CNS in a rat model for transgenerational transmission of drug addiction.
Radilová, Kateřina ; Černá, Marie (advisor) ; Rothová, Olga (referee)
Methamphetamine (MA) is a drug often abused by drug-addicted women and also is the mostly used drug in the Czech Republic. This drug crosses the placental and hematoencephalic barriers easily and therefore it can negatively affect not just mother herself, but also the development of the fetus. Even though there have been several published studies evincive negative effects of MA to posterity of drug-addicted mothers, the most critical term during pregnancy for the fetus remains unknown. In this study are examined CNS structures, which are directly influenced by methamphetamine action. Their function may lead to drug addiction through pleasurable feelings, such as reward feeling evoking. In the next chapter are analysed neurotransmitters and their transporters, which are related to methamphetamine effects. Studying their structure, localization or development during life may help to bring near the drug functioning in different life periods. Methamphetamine itself and its effects are closer described in the last part of this study. The problem of methamphetamine exposed fetus is outlined there - prenatal and postnatal so far known differences, but also sex differences in methamphetamine pharma- cokinetics.
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