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Seasonal dynamics of mats composed by green alga Zygnema (Zygnematophyceae)
Trumhová, Kateřina
The mats formed by Zygnema spp. are well known and frequently found in streams, puddles, seepages, and ponds. Owing to the low and inconsistent water quantity of these biotopes, algae are periodically subjected to stresses like desiccation, freezing, or strong solar radiation. Recent studies have revealed that Zygnema survives various stresses in pre-akinetes, modified resistant vegetative cells. However, earlier experiments mostly aimed at osmotic stress and desiccation. Moreover, the mats formed by these algae have seasonal dynamics that have been observed several times, not only in temperate conditions but also in the Arctic. Field observations revealed that most of the biomass is periodically lost, and new mats are formed every year. Simultaneously, we know little about the genetic composition of the mats and how it changes over time; previous work has focused mainly on the mats as an entirety. Therefore, this work mainly aimed to subject the mats formed by the algae Zygnema spp. to long-term observation and subsequent experiments. We selected a region in the Austrian Alps, which we visited several times a year, and sampled two sites with different water regimes. Further research in collaboration with colleagues occurred in the Arctic. Zygnema spp. strains were subsequently isolated from the...
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Seasonal dynamics of mats composed by green alga Zygnema (Zygnematophyceae)
Trumhová, Kateřina ; Pichrtová, Martina (advisor) ; Remias, Daniel (referee) ; Žárský, Jakub (referee)
The mats formed by Zygnema spp. are well known and frequently found in streams, puddles, seepages, and ponds. Owing to the low and inconsistent water quantity of these biotopes, algae are periodically subjected to stresses like desiccation, freezing, or strong solar radiation. Recent studies have revealed that Zygnema survives various stresses in pre-akinetes, modified resistant vegetative cells. However, earlier experiments mostly aimed at osmotic stress and desiccation. Moreover, the mats formed by these algae have seasonal dynamics that have been observed several times, not only in temperate conditions but also in the Arctic. Field observations revealed that most of the biomass is periodically lost, and new mats are formed every year. Simultaneously, we know little about the genetic composition of the mats and how it changes over time; previous work has focused mainly on the mats as an entirety. Therefore, this work mainly aimed to subject the mats formed by the algae Zygnema spp. to long-term observation and subsequent experiments. We selected a region in the Austrian Alps, which we visited several times a year, and sampled two sites with different water regimes. Further research in collaboration with colleagues occurred in the Arctic. Zygnema spp. strains were subsequently isolated from the...
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The effect of desiccation on streptophyte algae - mechanisms of stress resistance
Pošmourný, Martin ; Pichrtová, Martina (advisor) ; Vosolsobě, Stanislav (referee)
In this thesis I dealt streptophyta algae resistance against desiccation. Even though the area previously devoted only a few people. Considerable amount of work in recent years has been published on the subject. They were found interesting information and discovered new facts. Research continues on and on, and it would be useful to look at what was observed. I believe that understanding this phenomenon is the key to understanding some of the events in the evolution of nature and realizing how tough life can be on the very border of its possible occurrence. I tried to sort out the current knowledge about the mechanisms of stress resistance streptophyta algae and hope that I obtained an overview will help me understand better this issues. So far, it has been observed several approaches to defend against drying. Preventing drying, adaptation to water shortage and tolerance to desiccation. Among the preventive methods of defense include creating clusters of cells, multi-layered mats or secretion mucilage. As an adaptation to the lack of water algae evolved more complex answers in the form of changes in ultrastructure, or regulation of physiological processes. Klebsormidium is capable of half an hour to start the production of significant quantities callose and incorporate it into the cell wall. This...
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Differences in the level of aspiration and stress resistance of women floorball players Tatran Střešovice
Zabavská, Barbora ; Janák, Vladimír (advisor) ; Běhanová, Michaela (referee)
Title: Differences in the level of aspiration and stress resistance in female floorball players of Tatran Střešovice Objectives: The main aim of this research is to contribute to the search for a relation between the level of aspirations and performance in athletes. Furthermore, whether there is a difference in stress resistance in female floorball players of different ages. The general aim is to contribute to the current knowledge base in this area with new partial results based on the implementation of my own research investigation. Methods: The TATSO test was used for this research. The author of this version of the test is Janák, who modified the original test by Hošek from 1979 into its current form. The test measures the level of aspiration, resistance to stress and psychomotor tempo. The test is suitable for group investigations, but personal presence is required (it cannot be distributed electronically). It is a pencil-and-paper type of performance test. Results: I found that the older group of female floorball players had higher aspirations compared to the younger group, so the first hypothesis was confirmed. The second hypothesis, which states that the older group of female floorball players have higher load resistance, was not confirmed, as my research showed that both groups have the...
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Differences in the level of aspiration and stress resistence of women floorball players Tatran Střešovice
Zabavská, Barbora ; Janák, Vladimír (advisor) ; Běhanová, Michaela (referee)
Title: Differences in the level of aspiration and stress resistance in female floorball players of Tatran Střešovice Objectives: The main aim of this research is to contribute to the search for a relation between the level of aspirations and performance in athletes. Furthermore, whether there is a difference in stress resistance in female floorball players of different ages. The general aim is to contribute to the current knowledge base in this area with new partial results based on the implementation of my own research investigation. Methods: The TATSO test was used for this research. The author of this version of the test is Janák, who modified the original test by Hošek from 1979 into its current form. The test measures the level of aspiration, resistance to stress and psychomotor tempo. The test is suitable for group investigations, but personal presence is required (it cannot be distributed electronically). It is a pencil-and-paper type of performance test. Results: I found that the older group of female floorball players had higher aspirations compared to the younger group, so the first hypothesis was confirmed. The second hypothesis, which states that the older group of female floorball players have higher load resistance, was not confirmed, as my research showed that both groups have the...
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The effect of desiccation on streptophyte algae - mechanisms of stress resistance
Pošmourný, Martin ; Pichrtová, Martina (advisor) ; Vosolsobě, Stanislav (referee)
In this thesis I dealt streptophyta algae resistance against desiccation. Even though the area previously devoted only a few people. Considerable amount of work in recent years has been published on the subject. They were found interesting information and discovered new facts. Research continues on and on, and it would be useful to look at what was observed. I believe that understanding this phenomenon is the key to understanding some of the events in the evolution of nature and realizing how tough life can be on the very border of its possible occurrence. I tried to sort out the current knowledge about the mechanisms of stress resistance streptophyta algae and hope that I obtained an overview will help me understand better this issues. So far, it has been observed several approaches to defend against drying. Preventing drying, adaptation to water shortage and tolerance to desiccation. Among the preventive methods of defense include creating clusters of cells, multi-layered mats or secretion mucilage. As an adaptation to the lack of water algae evolved more complex answers in the form of changes in ultrastructure, or regulation of physiological processes. Klebsormidium is capable of half an hour to start the production of significant quantities callose and incorporate it into the cell wall. This...
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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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