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Abiotic Stress Adaptation in Plantago: mechanisms of tolerance
Dvořáková, Iveta ; Konrádová, Hana (advisor) ; Lhotáková, Zuzana (referee)
Plants are exposed to many adverse factors during their life cycles. Abiotic stresses are significantly limiting plant growth and development. Abiotic stress response mechanisms involve compatible solute synthesis (e.g. sugars, sugar alcohols and amino acids). The aim of this study was to characterise the responses of plants from Plantago genus to different abiotic stresses (drought, salinity, cold and stress combination). The complete plants grew under in vitro conditions. I compared morphological parameters, selected metabolic parameters (carbohydrates balance and proline accumulation) under optimal conditions and stress exposure. This study was focused on plants from genus Plantago, because they differ from each other in their tolerance to the salinity. Both, the glycophyte and the halophyte species are described within this genus. Plantains produce besides widespread soluble carbohydrates (sucrose, glucose, fructose) also sugar alcohol sorbitol, which has been reported as a significant component of the stress response. In addition, the reaction of plants to different carbon and energy sources was tested. More severe growth inhibition of the glycophyte Plantago lanceolata compared to the halophyte P. maritima was observed under salt treatment. Significant accumulation of sorbitol was observed...
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The physiological basis of abiotic stress tolerance in Fragaria genus plants.
Hamet, Jaromír ; Lipavská, Helena (advisor) ; Tylová, Edita (referee)
Abiotic stresses - drought, salinity or extreme temperatures - cause morphological and physiological changes, affect growth, development and plant productivity. In crops, these limitations often reduce yields up to 50%. Plants have developed various mechanisms ensuring some degree of abiotic stress tolerance, which undoubtedly include changes in carbohydrate metabolism. The nature of many defense mechanisms is not yet fully understood, moreover, most findings were obtained by studying model plants and little is known about their validity in crops. This work was therefore focused on woodland strawberry (Fragaria vesca L.) from economically important family Rosaceae. Controlled conditions and targeted exposure to stress factors was obtained through the cultivation in vitro. Strawberry plants and callus cultures were exposed to various stresses and their combinations, better reflecting the natural conditions. At various stages of stress reaction, growth characteristics, changes in the content and the spectrum of soluble carbohydrates and oxidative stress levels were monitored and compared with plants growing under optimal conditions. Abiotic stress responses of strawberry plants were very inhomogeneous, which complicated the obtaining of statistically significant results. The only significant response...
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Sorbitol role in abiotic stress response
Dvořáková, Iveta ; Konrádová, Hana (advisor) ; Janská, Anna (referee)
Many adverse factors affect plants during their life cycle. This bachelor thesis is focused on the influence of abiotic stress on plants. Attention is paid to drought and salinity stresses which are the main causes of osmotic stress, and to the mechanisms which help plants to cope with these adverse factors. Common reaction of plants to osmotic stress is synthesis and accumulation of substances which contribute to keeping cell integrity. These substances are called compatible solutes. This thesis is focused on sorbitol - sugar alcohol belonging to this group of substances. In plants that synthesize sorbitol naturally, it provides advantage under exposure to abiotic stresses as it serves as an osmoticum and/or an osmoprotectant and reduces oxidative stresses. Finally, based on the knowledge about participation of sugar alcohols in the stress reactions, modifications of plant metabolisms potentially increasing stress tolerance are discussed. Powered by TCPDF (www.tcpdf.org)
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Genetic variability in growth, reproductive and photosynthetic parameters of plants and its changes by exogenously applied steroids
Rothová, Olga ; Holá, Dana (advisor) ; Motyka, Václav (referee) ; Hradilík, Jan (referee)
While animal steroid hormones are very well known and have been studied for a long time, in plants no steroid substances were known until relatively recently. Only in the second half of the past century brassinosteroids were discovered; later on, their hormonal function in plants was confirmed. Still a lot of unknown remains as regards their function in plant cells. This paper presents in its first part the evidence that brassinosteroids control in maize (Zea mays L.) grown under field conditions not only its morphology and yield but also some developmental/reproduction characteristics like e.g. number of female inflorescences or speed of the development of male inflorescences. Particular response of a plant depends, however, on the type of applied brassinosteroid, its concentration, and last but not least also on a particular maize genotype and developmental stage of the plant during applicatin. Impact of brassinosteroids on primary photosynthetic processes in plants has not been proven under these conditions, neither on the activity of photosystem (PS) I nor on the Hill reaction. No statistically significant differences in the content of photosynthetic pigments have been found either. Another topic dealt with in this thesis is the possible protective influence of brassinosteroids on plants...
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Trehalose metabolism gene manipulations and improving plant abiotic stress tolerance
Hamet, Jaromír ; Lipavská, Helena (advisor) ; Hála, Michal (referee)
In these days, genetic modifications of crops are commonly used in the fight against pests and weeds. More and more often there are also efforts to use genetic modifications to increase tolerance to abiotic stresses that affect worldwide yields much more than biotic ones. Manipulation of trehalose metabolism represents one of the frequently studied options of abiotic stress tolerance enhancement. This work summarizes current knowledge on the protective effects of trehalose in cells and describes signaling functions of trehalose and its metabolic intermediate trehalose-6-phosphate in plants. It also describes current achievements in increasing abiotic stress tolerance through genetic modifications of trehalose metabolism together with accompanying problems. Finally, the potential of this method for future exploitation is discussed.
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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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The proteomic study of abiotic stress of plants.
Barabášová, Kamila ; Podlipná, Radka (advisor) ; Smrček, Stanislav (referee)
Keywords: Arabidopsis thaliana, phytoremediation, abiotic stress, ibuprofene, doxorubicin, two-dimensional electrophoresis Nowadays, develop of the pharmaceutical industry is very fast. Reason of this trend is ever-increasing number of diseases, lifestyle and still increasing demand for the drugs. With this trend growing interest in the analysis of the residues of pharmaceuticals in the environment which is result of incomplete wastewater treatment. This diploma thesis is studying effect of cytostatic drugs, specifically doxorubicin and one of the most widely used analgesics - ibuprofen, at the proteome level of the model plant Arabidopsis thaliana. Proteins isolated from plants exposed to the drugs were separated by two-dimensional electrophoresis. Comparing of protein maps by PDQest program (Bio-Rad, USA) was found several proteins whose expression was affected by the presence of drugs in the culture medium. Selected proteins were identified by LC - MS / MS.
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Regulation of cytokinin metabolism in tobacco plants and chloroplasts
Havlová, Marie ; Vaňková, Radomíra (advisor) ; Ryšlavá, Helena (referee) ; Malá, Jana (referee)
Cytokinins (CKs) are one of the most important group of phytohormones influencing many processes throughout the whole plant. As many processes are regulated both by the light and phytohormones, the first part of this work has been focused on evaluation of diurnal rhytmicity in levels of cytokinins and other cooperating hormones like auxin (indol-3-acetic acid, IAA), abscisic acid (ABA) and polyamines (PA). The changes in activity of selected enzymes participating in metabolism of the above mentioned phytohormones were followed as well. Diurnal variation of phytohormones was tested in tobacco leaves (Nicotiana tabacum L. cv. Wisconsin 38) grown under a 16/8 h (light/dark) period. The main peak of the physiologically active forms of CKs, found after the middle of the light period, coincided well with the maximum of IAA and PA levels and with activity of the corresponding enzymes. The achieved data indicate that metabolism of CKs, IAA and PAs is tightly regulated by the circadian clock. The other part of the study has been focused on changes in the contents of CKs, IAA and ABA in transgenic tobacco plants with altered cytokinin metabolism, achieved via the over-expression of particular enzymes participating in CK metabolism (biosynthesis, degradation and reversible conjugation). As CKs are known to be...
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Study of cytokinin role in abiotic stress response
Dobrá, Jana ; Vaňková, Radomíra (advisor) ; Ryšlavá, Helena (referee) ; Brzobohatý, Břetislav (referee)
Plants had to evolve, due to their sessile growth habit, a complex system of defence against adverse environmental conditions. Plant abiotic stress responses are regulated by plant hormones, especially by cytokinins (CKs) and abscisic acid (ABA). In order to evaluate the effect of enhanced stress tolerance on the dynamics of hormones (CKs, auxin and ABA) as well as polyamine levels during the drought and/or heat stress (HS) progression, response of tobacco plants with enhanced level of osmolyte proline was compared with the corresponding wild-type. HS (40řC) caused a transient increase in bioactive CK content, accompanied by decrease of ABA, which indicated stimulation of transpiration, important mechanism to cool down the leaf temperature at the early phase of HS. Simultaneously, a transient increase in spermidine and spermine levels was found, more profound in proline-over-producing transformant. The activities of particular polyamine metabolic enzymes correlated well with their content. Drought stress resulted in the establishment of a gradient of bioactive CKs in favour of the upper leaves, crucial for their preferential protection. Application of HS at the end of drought period strongly enhanced the stress severity, mainly due to additional water loss caused by enhanced transpiration....
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The role of polyploidisation in the evolution of the genus Chenopodium with a focus on Chenopodium quinoa
Babčanová, Natália ; Štorchová, Helena (advisor) ; Cvrčková, Fatima (referee)
Chenopodium is a cosmopolitan paraphyletic genus. Belongs to the Amaranthaceae family and the Chenopodioideae monophyletic subfamily. Diploid, tetraploid and hexaploid species are found in almost all evolution branches of Chenopodioideae, in the case of Chenopodium album, different degrees of ploidy occur within a single species. The degree of ploidy is an important factor in the study of evolution and phylogenetic relationships between Chenopodium species and it also affects the speciation and morphology. The genus Chenopodium includes weeds as well as cultivated crops, such as Chenopodium quinoa, Ch. pallidicaule, Ch. ambrosioides or Swaeda foliosa. Quinoa (Chenopodium quinoa) is the best known species of the Chenopodium genus. It is an allotetraploid (2n = 4x = 36), derived from the same albeit not yet known diploid parents as a closely related tetraploid Ch. berlandieri. Some of its alleles segregate as in a functional diploid, which complicates genetic analyses and breeding efforts. This species features high genetic variability due to gene flow between weed and crop populations and some other evolution processes that are affected by polyploidy. Quinoa is referred to as a pseudocereal and it has been used as a crop in South America as early as in the Inca times. It can survive at locations unsuitable...
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