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The phenomenon of Foliar Water Uptake - mechanisms and consequences with a focus on temerate plant species
Oramová, Viktorie ; Lhotáková, Zuzana (advisor) ; Ponert, Jan (referee)
The ability of plants to absorb water through leaves has been a matter of the sientific discussion for a long time. Among the epiphytic species (tilandsies for example), reduced root system and foliar water uptake (FWU) is considered an adaptation for life in soil-less environment, and FWU is a necesssity. It was surprising, that the same ability has been discovered in plant species with normally developed root system. Over the time, new pieces of evidence about FWU in broad range of plant species has been published and FWU is getting universal for all plants, across the taxonomic groups or biomes, including temperate zone. The systematic focus on FWU and continuity of its research is lacking and therefore the knowledge about FWU is still only partial. This bachelor's thesis is focused on mechanisms of FWU and the leaf structures that may mediate it. The ability of water to pervade cuticle through aquatic pores is discussed, together with the possibility of water absorption by stomata, trichomes, hydathodes or epiphylic organisms. Another discussed topic is the use of this water by plant - improving of the water regime, refilling of the embolized xylem vessels, possible exudation by roots etc. The matter of FWU has other consequences on the ecosystem level, like in water cycle or the plant's...
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Determination of chlorophyll content in selected grass communities of Krkonoše tundra based on field spectroscopy and aerial hyperspectral data
Pinlová, Gabriela ; Červená, Lucie (advisor) ; Lhotáková, Zuzana (referee)
The thesis focuses on the determination of chlorophyll content from hyperspectral data in grass communities in the arctic-alpine tundra in the Krkonoše Mountains, namely Nardus stricta, Molinia caerulea, Calamagrostis villosa, and Deschampsia cespitosa. Leaf chlorophyll content (LCC) was measured using two methods - spectrophotometric destructive determination in the laboratory, and the LCC assessed non-destructively by fluorescence portable chlorophyll meter CCM-300. Leaf area index (LAI) values for canopy chlorophyll content (CCC) retrieval were also acquired by destructive biomass sampling and indirectly using LAI-2200C. Relationships were established between the LCCs, LAI, CCCs, and vegetation indices (VI) calculated from respective spectra, i.e. leaf level spectra acquired with contact probe coupled with an ASD FieldSpec4 Wide-Res spectroradiometer, canopy level spectra measured by the spectroradiometer and extracted from hyperspectral images (HSI) acquired by Headwall Nano- Hyperspec® mounted on the DJI Matrice 600 Pro drone. Chlorophyll content maps were created based on the results of multiple stepwise linear regression applied to HSI. For the model, derived from the non-destructive data sampling and used for the LCC map, a RMSE of 66.55 mg/m2 was achieved. Keywords: leaf chlorophyll...
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Water use efficiency (WUE), its definition and importance in plant resistance against osmotic stress
Jedlička, Tomáš ; Hála, Michal (advisor) ; Lhotáková, Zuzana (referee)
Water is one of the main limiting factors of plant growth. Availability of water on our planet is decreasing, and if we add fast-growing human population, we have a problem growing. Scientists from all around the world, especially those from arid regions, are facing a big problem, which is an attempt to make the most efficient use of water by plants. If this problem should be solved, we need to understand the issue of Water Use Efficiency (WUE). This paper attempts to summarize the current knowledge related to the issue of WUE, mainly focused on anatomical and physiological parameters control of WUE, which is focused primarily on the issue of evapotranspiration. Another part focuses on clarifying the issue of WUE at the gene level and the related biotech opportunities. At the end of the work are discussed possibilities of increasing WUE using irrigation techniques. Key words: water use efficiency, evaporation, transpiration, stoma, stomatal density, abscisic acid, ERECTA
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Photosynthetic parameters as secondary selection traits during plant breeding for salt stress tolerance
Hlavatá, Věra ; Kočová, Marie (advisor) ; Lhotáková, Zuzana (referee)
High salt concentration is important abiotic stress factor that negatively affect plant growth and development and finally also their yield. Increase of plant tolerance to this stress factor is thus one of the most important goals in breeding programmes, particularly in areas with saline environment. Various physiological traits have been suggested for the testing of plant tolerance to improved salinity. Photosynthetic parameters play undoubtedly the main role, because of their rapid response to stress conditions. Generally, photosynthetic rate, chlorophyll content and chlorophyll fluorescence belong to the photosynthetic parameters, that are usually recommended for the evaluation of stress tolerance. All of them were also used for study of salt tolerance in crop plants. The advantages of these measurements are rapidity, non-invasive techniques and particularly, the possibility to test wide collection of genotypes during the short period. Although some of the parameters were recommended for the evaluation of stress tolerance, the results are still ambiguous. The aim of this study was to briefly describe the changes of selected photosynthetic parameters of different plant species in consequence of salt stress and assess the usefulness of these parameters for reliable screening for salt tolerance.
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Hydraulic redistribution and within community plant relations
Lörinc, Filip ; Lhotáková, Zuzana (advisor) ; Tylová, Edita (referee)
Hydraulic redistribution is a widespread process of passive water transport through the plant root system along the gradient of water potential. This process significantly affects other plant belowground and aboveground processes. Water can be transported in several directions by hydraulic redistribution. The aim of the first part of this thesis is to summarize the knowledge about the operation of hydraulic redistribution. It describes the causes and consequences of the hydraulic redistribution as well as its main types. Subsequently, mainly vertical hydraulic redistribution is observed, the main components of which are the hydraulic lift and the hydraulic descent. The second part focuses on how vertical hydraulic redistribution can influence the interactions among plants and the functioning of the whole ecosystem. The answer to this question is sought in the savanna plant life, which is composed of scattered trees and their grassy understory. Savanna plants are exposed to dry and wet seasons, which creates a changing soil gradient of water potential throughout the year, which is of great interest for hydraulic redistribution research. This thesis shows that woody species have a competitive advantage over the grassy understory due to the presence of a hydraulic descent. Competition between trees...
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Study of Coniferous Needles in Relation to Environmental Factors Using Approaches of Quantitative Anatomy and Laboratory Spectroscopy
Lhotáková, Zuzana ; Albrechtová, Jana (advisor) ; Šantrůček, Jiří (referee) ; Lukac, Martin (referee)
SYNTHESIS - CONCLUSIONS: This thesis combines two methodical approaches at different hierarchical levels of plant ecophysiology, which both are applied in field research and bring new valuable information for comprehension of several aspects of carbon cycle in forest ecosystem, particularly coniferous. The quantitative anatomy represents the first approach. At the leaf level application of confocal microscopy on fresh and frozen-stored needles and subsequent stereological estimation of mesophyll geometrical parameters proved to be suitable and sensitive enough for estimation of changes in mesophyll after simulated acid rain or differentiation of sun and shade needle ecotype. Application of systematic uniform random sampling of sections along the needle axis revealed insight to heterogeneity of mesophyll geometrical parameters within the needle and confirmed representativeness of the sampling from the middle region of the spruce needles. The second approach, laboratory measurement of shoot reflectance, represents important step in verification of relationships between leaf biochemical and optical properties, which can be subsequently used for monitoring of forest health, foliar or soil chemistry using remote sensing techniques. At the level of Norway spruce crown, samples of even-aged needles from the upper...
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Lateral root development in response to mineral nutrients; signal mechanisms and pathways.
Halamková, Daniela ; Tylová, Edita (advisor) ; Lhotáková, Zuzana (referee)
TTL3 gene was identified by forward screening of genes involved in lateral root development in Arabidopsis thaliana based on its expression pattern. TTL3 belongs to the TTL (TETRATRICOPEPTIDE-REPEAT THIOREDOXIN-LIKE) gene family. The diploma thesis is aimed on characterisation of changes in TTL1, TTL3 a TTL4 promotor activities in response to external conditions (availability of nitrogen or phosphorus) that affect root growth. Obtained data should elucidate possible relation among TTL gene expression activities, root growth rate, and apical meristem activity. Nitrogen or phosphorus deficiency triggered changes in root growth and root system morphology of experimental plants. Short-term nitrogen deficiency stimulated root growth. Short-term phosphorus deficiency induced gradual growth cessation in main root and long laterals. Long-term deficiency reduced root growth of both N-deficient and P-deficient plants compared to control. The root system size of N-deficient and P-deficient plant was almost similar. Determination of promotor activity using β-glucuronidase reporter gene showed changes in expression activity and its localization in response to root growth intensity. TTL4 gene promotor activity was the most responsive. Its activity was generally higher in slowly growing roots, particularly under...
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Mechanisms of extreme drought tolerance in resurrection plants
Termanini, Sebastian ; Lipavská, Helena (advisor) ; Lhotáková, Zuzana (referee)
Drought is one of the abiotic stresses that plants have to fight with from the beginning of their transition to land. However, there is a systematically incoherent group of plants that can solve extreme water scarcityand still effectivelyprosper. A high degree of dehydration involves a number of problems including osmotic stress, the accumulation of reactive oxygen species (ROS), or protein degradation. However, drought-tolerant plants have evolved mechanisms to deal with these problems. For protection against ROS they activate antioxidant enzymes and accumulate non-enzymatic antioxidants, which can quench ROS. These plants use a wide spectrum of amino acids and carbohydrates against the osmotic stresses, ranging from the ubiquitous and abundant carbohydrates like sucrose, till the trehalose scarce in plants. None of the plants relies on a single substance, instead, plants depend on species-specific cocktails of protective agents, through which they acquire their tolerance. The studies of those plants and their mechanisms of tolerance seem to be a perspective way for selection of preferable target genes suitable for the development of crops tolerant to desiccation. Key words: antioxidant systems, dehydration, drought, LEA, octulose, polyols, RFO, resurrection plants, sucrose, trehalose
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Effect of water supply on structure and selected physiological parameters of leaf in woody species.
Horešovská, Michaela ; Lhotáková, Zuzana (advisor) ; Votrubová, Olga (referee)
Woody plants must cope with drought as it is one of the main factors of the ongoing climate change. The ability of woody plants to adapt to this stressor determines whether they will survive in constantly changing environmental conditions. The deciduous trees of European temperate forests are not as adapted to drought as Mediterranean trees and shrubs, and therefore the lack of water is a major stress for them. Leaf turned out to be the most flexible plant organ in its response to drought. The aim of this work is to summarize the knowledge about the effect of water deficit on the anatomical structure of leaf and its selected physiological parameters. The first part of this thesis is focused on the drought affecting European tree species and their various defensive strategies against this factor. It mainly describes the modification of leaf's anatomy structure as their defensive reactions observed in dermal, ground and vascular tissue. The second part of this thesis is devoted to the influence of water deficit on the selected leaf's physiological processes, especially on transpiration and photosynthesis, and the key role of stomata closure on both of these physiological processes. Drought causes changes in leaf anatomical structure and its physiological functions. The leaf's developmental stage at...
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Increasing plant drought resistance by priming methods: the role of antioxidant capacity changes
Popelářová, Anna ; Lipavská, Helena (advisor) ; Lhotáková, Zuzana (referee)
When there is a lack of water in the soil, the plant is subject to stress during which reactive oxygen species (ROS) are formed and the water content in the tissues decreases. ROS cause oxidative damage, which the plant tries to prevent by antioxidation systems action. The osmotic adjustment process ensures water maintenance in the plant. Priming can be thought of as a treatment of plants aimed at increasing stress resistance. This thesis is mainly focused on summarizing information related to priming in connection with drought tolerance improvement and related changes in the activities and amount of antioxidation systems and osmolytes. So far, seed priming methods are probably the most explored, these include hydropriming, osmopriming and priming with elicitors. Priming in the vegetative phase of growth is mainly associated with the application of elicitors. Transgenerational priming has an impact on the progeny of treated plants. Priming-induced changes are species-specific and in some cases may affect the plants for a longer period.
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