National Repository of Grey Literature 25 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
Intraspecific and intraclutch variability of avian egg
Králová, Barbora ; Jelínek, Václav (advisor) ; Sedláček, Ondřej (referee)
Egg-laying birds have a huge variation between species in terms of number, size, pigmentation, but also in the speckled nature of the eggs. Bird eggs vary not only between species, but also within species, even within a clutch. It is only recently that more speculation has begun about the possible causes of intraspecific variation. Hypotheses about intraclutch variation started to emerge even later. This thesis presents and describes some of the hypotheses dealing with egg variability. One of the most significant factors affecting intraspecific variability is food availability, which in turn affects female fitness. For intraclutch variability, most studies focus on the difference between the last egg and other eggs within the clutch. In many cases, the last egg has a size difference, but also a different amount of pigment compared to the other eggs in the clutch, which are not significantly different from each other.
The phylogeny of the Protaetia Burmeister, 1842 flower beetles in the western palearctic region
Žďárská, Kateřina ; Šípek, Petr (advisor) ; Bezděk, Aleš (referee)
This diploma thesis deals with the phylogeny and phylogeography of flower beetles of the genus Protaetia, especially with the complicated taxonomic complex around the species Protaetia (Potosia) cuprea, P. cuprina and P. caucasica in the western Palearctic region. In light of the results presented by Vondráček et al. (2018), it seems that the classic taxonomic approach, based only on coloration, geographical distribution or poorly analysed morphological characters, is not able to adequately explain the evolution of the taxon, nor correctly identify individual taxa at the species level (i.e. species and subspecies). To understand the evolution of the group and the population structure, it is therefore necessary to use the now standard molecular-phylogenetic approaches as well. Based on analyses of one nuclear (internal transcribed spacer 1) and two mitochondrial genes (cytochrome oxidase I and cytochrome b) from 231 individuals, a phylogenetic hypothesis of the West Palaearctic representatives of the genus Protaetia was compiled. It was found that the currently recognized subgenera of the genus do not correspond to the results of the analyses. The subgenera Eupotosia, Netocia and Potosia proved to be non- monophyletic. Within the species complex of P. cuprea, in addition to the European clade of P....
Species delimitation in Aspergillus section Candidi
Glässnerová, Kateřina ; Hubka, Vít (advisor) ; Caboň, Miroslav (referee)
Aspergillus section Candidi encompasses white- or yellow-sporulating species mostly isolated from indoor and cave environments, soil, food, feed, clinical material and dung. Their identification is non-trivial due to largely uniform morphology. This work aims to re- evaluate the species boundaries in the section Candidi and present an overview of all existing species along with information on their ecology. For this work, a set of 113 strains of different origins was gathered. DNA sequences of the genes for β-tubulin (benA), calmodulin (CaM), and the second largest subunit of RNA polymerase (RPB2) were used for molecular analyses, and species delimitation methods based on a multispecies coalescent model were applied. Classical phylogenetic methods and the genealogical concordance species recognition approach were used for comparison. Phenotypic studies involved comparisons of macromorphology on four cultivation media, seven micromorphological characters and growth in temperatures ranging from 10 to 45 řC. For the final decision about species boundaries, an integrative approach consisting of four criteria was defined, based on which seven existing and two undescribed species were supported. The revised section Candidi comprises nine species, some of which manifest a high level of intraspecific...
A possible role of proline in plant stress memory
Ušák, David ; Holá, Dana (advisor) ; Konrádová, Hana (referee)
The previous exposure to abiotic stress such as drought may prime plants, leading to their improved response upon later stress onset. This phenomenon, called plant stress memory, is linked to a plethora of mechanisms exerted on several levels. A complex analysis of proline metabolism in leaves and roots was performed to test the putative role of proline in such response to recurrent stress, represented by two periods of water deficit, interrupted by a period of rewatering during recovery. To provide a better understanding of intraspecific differences in drought stress memory response of plants and its inheritance, maize (Zea mays L.) parental genotypes with differing drought sensitivity and their F1 reciprocal hybrid offspring were chosen as the plant material. The water deficit had a more pronounced effect on proline metabolism in leaves than in roots. The proline content increased in response to drought, which was linked to a higher proline biosynthesis and a lower proline catabolism. Marked differences in proline metabolism among genotypes were observed, confirming the previous findings that recurrent drought response is not conserved even within the same species. However, contrary to the original assumptions on the role of proline in plant stress memory, the statistical analysis showed that...
Craniometric study of Central European populations of the white-toothed shrews Crocidura suaveolens and C. leucodon (Mammalia: Soricomorpha)
Milerová, Petra ; Vohralík, Vladimír (advisor) ; Anděra, Miloš (referee)
Interspecific and intraspecific size variability of the skull, mandibles and teeth of the lesser white- toothed shrew Crocidura suaveolens and the bicolored white-toothed shrew C. leucodon was studied on material of 350 skulls and 465 mandibles of white-toothed shrews obtained by analysis of the barn owl pellets originating from four regions in the Czech Republic and one region in the southern Slovakia. C. suaveolens was present in all regions under study, while sympatric C. leucodon occurred in three regions only. In total, 21cranial and dental measurements and 4 mandibular measurements were investigated. It was found that the most reliable measurement enabling discrimination between skulls of both species in the whole studied material is the lenght of the lower dental row. If skulls of both species were evaluated separately for each area of their sympatry it was possible to use also the distance between second molars M2 and the width of premolar P4 . Skulls of these two species can also be distinguished by bivariate graphs using the length and width of premolar P4 and the palatal length. We studied relationships between cranial measurements of both species and geoclimatic factors such as longitude, latitude, mean annual temperature and mean annual percipitation. It was found that variability of...
Intraspecific variability in plant antioxidant systems and its impact on drought tolerance
Jelénková, Iva ; Kočová, Marie (advisor) ; Zelenková, Sylva (referee)
Drought is one of the major factors limiting agricultural production. Reactive oxygen species (eg. superoxide radical, hydroxyl radical, hydrogen peroxide) generated during stress in plant cells activate antioxidant mechanisms, which scavenge those toxic substances. The positive correlation between activity of enzymatic (eg. catalase, superoxide dismutase, glutathione reductase, peroxidases) and nonenzymatic (eg. glutathione, ascorbic acid) antioxidants and stress tolerance was confirmed in various studies. Both interspecific and intraspecific variability was found in activities of antioxidant systems of plants. Higher activity was also observed in F1 generation in relation to positive heterosis, or in plants treated with supportive substances such as abscisic acid, brassinosteroids and nitrogen. The increase in the activity of antioxidants was also proved in relation to the ploidy level or to intensity of drought. It was observed the positive effect of previous drought exposition on tolerance to other abiotic stressors. The complex response of plants to stress factors depends on many other internal and external factors.
Geographical variation of localisation in vertebrates
Cinerová, Michaela ; Petrusková, Tereza (advisor) ; Turčoková, Lucia (referee)
Sound expressing is common for a big amount of animal species, mostly when communicating with individuals of their own or other species. Acoustic communication can be used especially in situations or in the environment where an individual does not see a signal receiver well (confusing environment, at night or long distance). It's well-known that the individual species have their own characteristic acoustic expressions. However, these can differ also within the species itself, either in time or in space. This study is concerned just with variability of inter-species vocal communication of all vertebrates in space. Its purpose is to map at which animal species vocalization vary in space. Furthermore, it deals with searching for causes of origin of this variability, such as genetic differences among particular groups of populations, environmental and learning effects etc. within various animal species. In the last part, it tries to answer the question whether the spatial variability of acoustic signals could influence separation of new species and thus have evolutionary consequences.
Different response of maize inbred and hybrid genotypes to drought: analysis of leaf proteome and photosynthetic processes
Benešová, Monika ; Holá, Dana (advisor) ; Prášil, Ilja (referee) ; Pospíšilová, Jana (referee)
Drought is one of the most important stress factors affecting plants. Increasing drought resistance via plant breeding is currently the main approach for improvement of plant productivity and reduction of water usage. Plant breeders and scientists search for reliable and easy methods of the determination of drought sensitivity in different genotypes. A precise knowledge about processes underlying plant stress response and defence against limited water availability is necessary for this. The aim of this study was a detailed analysis of photosynthetic processes and changes in leaf proteome (again aimed especially at proteins involved in photosynthesis) during drought stress. This analysis was a part of a complex project focused on the possible causes of genetic variability and drought resistance in agronomically important crops. Another goal was to analyse whether the measurement of selected photosynthetic parameters can be used for the determination of drought sensitivity per se and/or for the prediction of the response of hybrids based on known behaviour of their parents. Young plants of maize inbred lines and their hybrids were used as a model for this analysis, which was made under conditions of moderate and more severe drought. Two inbred lines which were (together with their F1 hybrids) used...
Morphological variation of Cameroonian sunbirds
Bovšková, Denisa ; Hořák, David (advisor) ; Chmelová, Eliška (referee)
5 Abstract Morphological traits give information about the adaptations of the studied species, the resources, which it uses, and they can generally tell us about the use of ecological space. Intraspecific morphological variability reflects various adaptations of local populations thus variability reflect different way of life. The subject of this thesis is an ecologically interesting group of specialized tropical songbirds - Sunbirds (Nectarinidae). The taxon exhibits number of adaptations to specific food collecting a combination of nectarivory and insect hunting. I focused here on the intraspecific variability of three species (Cyanomitra oritis, Cinnyris reichenowi and C. bouwieri) living in different habitats in Cameroon. The aim of this work was to find out in what morphological characters are this species sexually dimorphic. Furthermore, if their populations living in remote locations differ? Finally, if all studied species show similar trend of intraspecific variability of the traits, which could have common ecological causes. The following traits were measured: wing and tail feather length, beak dimensions, total body weight and other characters. The analysis is based on field data collected between 2003 and 2015 and museum collections. Overall, we collect information about ca. 1200 individuals for...
Different response of maize inbred and hybrid genotypes to drought: analysis of leaf proteome and photosynthetic processes
Benešová, Monika
Drought is one of the most important stress factors affecting plants. Increasing drought resistance via plant breeding is currently the main approach for improvement of plant productivity and reduction of water usage. Plant breeders and scientists search for reliable and easy methods of the determination of drought sensitivity in different genotypes. A precise knowledge about processes underlying plant stress response and defence against limited water availability is necessary for this. The aim of this study was a detailed analysis of photosynthetic processes and changes in leaf proteome (again aimed especially at proteins involved in photosynthesis) during drought stress. This analysis was a part of a complex project focused on the possible causes of genetic variability and drought resistance in agronomically important crops. Another goal was to analyse whether the measurement of selected photosynthetic parameters can be used for the determination of drought sensitivity per se and/or for the prediction of the response of hybrids based on known behaviour of their parents. Young plants of maize inbred lines and their hybrids were used as a model for this analysis, which was made under conditions of moderate and more severe drought. Two inbred lines which were (together with their F1 hybrids) used...

National Repository of Grey Literature : 25 records found   1 - 10nextend  jump to record:
Interested in being notified about new results for this query?
Subscribe to the RSS feed.