|
|
Allometric diversity and plasticity of cellular morphologies of desmids (Desmidiales, Zygnematophyceae)
Mezník, Daniel Heliodor ; Neustupa, Jiří (advisor) ; Kleisner, Karel (referee)
If the proportions of two features of an organism change during its growth, their relationships can be described as allometry. The first partof this thesis quantifies the allometric relationship of semicellular perimeter and area of 11 species of unicellular microalgae from the genus Euastrum. These algae are recognized for their fractalmorphology, which is theorized to be an adaptation for increasing their surface area which is used to absorb nutrients.Thequestion was whether larger individuals within a population have a more complex shape and therefore a longer perimeter. I examined microphotographs of tens of semicells obtained from preserved wild populations. All included species exhibited a marked increase in shape complexity. The same trend could be noticed on and interspecific level. I compared these results to existing studies conducted on the related Micrasterias lineage. The second part of this thesis deals with allometric changes during semicells ontogeny in both Euastrum and Micrasterias. I analyzed growing clonal cultures using geometric morphometry. Specifically, I observed the relative position of 11 structurally homologous landmarks on semicells of different ages. This has been the first experiment of its kind on these model organisms. Idescribed theontogenetic change in landmark...
|
|
|
Geometric morphometrics of shape and symmetry of flower structures - ecological and evolutionary significance
Rubešová, Veronika ; Neustupa, Jiří (advisor) ; Woodard, Kateřina (referee)
I did a research of relevant literature on geometric morphometrics, its usage for a study of floral symmetry, and ecological and evolutionary significance of floral symmetry in general. Description and application of morphometric methods is included in the first part of the thesis. Then, the main types of floral symmetries are described and illustrated. Morphometric studies on several model floral lineages are discussed in subsequent parts of this bachelor thesis. Many of the studies are made on some species of family Brassicaceae. Modern morphometric methods and perspectives of their application in floral research are presented in the last chapter.
|
|
| |
|
|
Assessing the threat of hybridization between Prunus fruticosa and cultivated Prunus species
Musilová, Lenka ; Vít, Petr (advisor) ; Chrtek, Jindřich (referee)
Presented thesis evaluates the risk of ongoing hybridization (antropohybridization) in highly endangered Prunus fruticosa in the Czech Republic and selected adjacent countries. Absolute genome size analysis (estimated by flow cytometry) combined with both numeric and geometric morphometrics were used for evaluation of hybridization. Prunus fruticosa frequently hybridize with naturalized Prunus cerasus (emerging tetraploid hybrid Prunus ×eminens) and native Prunus avium (forming triploid hybrid Prunus ×mohacsyana). Discrimination between P. ×eminens and P. ×mohacsyana is difficult, when using leaf morphology characters only, so the occurrence of triploid hybrids was strongly underestimated in the Czech Republic (only tetraploid hybrids were reported). Both hybrids are surely differentiated using flow cytometry analysis (based on different ploidy level). The majority of analyzed populations is formed by either individuals of pure P. fruticosa or one of the mentioned hybrids. Only four populations were mixed. Continuous variability in absolute genome size was found in two of them, which may indicate hybrid swarm forming (incl. primary hybrids and backcrosses). Our findings can be considered only as indirect evidence for introgression, which needs to be confirmed by molecular markers (for example...
|
|
|
Geometric morphometrics of diatom frustules.
Hubáčková, Kateřina ; Kulichová, Jana (advisor) ; Pichrtová, Martina (referee)
This bachelor thesis includes a theoretical and a practical part. In the theoretical part, I focused problematic parts of research of diatoms biology. I will discuss morphology of specific silica scale and its morphogenesis; life cycle, characteristic by the size diminution in vegetative phasis, and conception of taxonomy of these organisms which is rather complicated because of unclear species concept. Another part presents tools of geometric morphometrics which is rapidly developing method for investigation and quantification of biological shape. In the practical part, I present the results from own research. This experiment is preliminary study for diploma thesis and its purpose is to appropriate tools of geometric morphometrics and to present advantages of its methods. I will investigate morphological disparity of three strains of pennate diatoms cultivated in standard conditions studied by landmark methos. The aim of this study is to discover if small cells which have gone trough the long phasis of vegetative multiplication and are close to the sexual reproduction have diferent degree of morphological variability than the bigger ones just undergone by sexual process.
|
|
|
Diversity and distribution of the Euastrum humerosum / didelta (Desmidiales) species complex
Kupčíková, Eva ; Šťastný, Jan (advisor) ; Kollár, Jan (referee)
From 23 European and North American strains Euastrum humerosum/didelta species complex (Desmidiales) I have obtained 3 lineages in molecular marker trnGucc group II intron. I did not acquire significant and homogenous results in SSU intron. It is probable that the lineages of trnGucc intron are very young. SEM revealed one central pore in cell wall and five bulges. The lineages were significantly different in their shape and dimensions. The lineages differentiated mainly in their length and breadth of the cells. The lineages inside morphotype E. humerosum differentiated in shape and dimensions of the polar lobe. The lineages inside morphotype E.didelta differentiated in shape and dimensions of the neck. That was ascertained using the geometric morphometrics with the measuring. Linear discriminant analysis of the desmids from literature revealed that is possible to partly discriminate groups of the varieties (E. humerosum var. parallelum and E. didelta in lineage A; two formae E. didelta f. val Piora and E. didelta f. latior in lineage B; E. didelta var. inermiforme and E. humerosum var. affine in lineage C). Key words: desmids, species, hidden diversity, molecular phylogenetics, geometric morphometrics, Euastrum, scanning electron microscopy
|
|
|
Diversity and distribution of the Euastrum humerosum / didelta (Desmidiales) species complex
Kupčíková, Eva ; Šťastný, Jan (advisor) ; Kollár, Jan (referee)
From 23 European and North American strains Euastrum humerosum/didelta species complex (Desmidiales) we have obtained 3 lineages in molecular marker trnGuuc group II intron. We did not acquire significant and homogenous results in SSU intron. It is probable that the lineages are very young. The lineages were significantly different in their shape and dimensions. We used the geometric morphometrics with the measuring of the lengths and breath of the semicells, isthmus and their ratios. The lineages differentiated in their dimensions and shape variable polar lobes and neck. SEM revealed the one central pore in cell wall on the contrary, with variant E. didelta var. bengalicum, which has two pores according the literature records. Key words: desmids, species, hidden diversity, molecular phylogenetics, geometric morphometrics, Euastrum, scanning electron microscopy
|
|
|
Geometric morphometrics of shape and symmetry of flower structures - ecological and evolutionary significance
Rubešová, Veronika ; Neustupa, Jiří (advisor) ; Woodard, Kateřina (referee)
I did a research of relevant literature on geometric morphometrics, its usage for a study of floral symmetry, and ecological and evolutionary significance of floral symmetry in general. Description and application of morphometric methods is included in the first part of the thesis. Then, the main types of floral symmetries are described and illustrated. Morphometric studies on several model floral lineages are discussed in subsequent parts of this bachelor thesis. Many of the studies are made on some species of family Brassicaceae. Modern morphometric methods and perspectives of their application in floral research are presented in the last chapter.
|
|
|
Cryptic and pseudocryptic diversity of conjugating green algae (Zygnematophyceae)
Kupčíková, Eva ; Šťastný, Jan (advisor) ; Škaloud, Pavel (referee)
This bachelor thesis summarizes the most commonly used species concepts in the class Zygnematophyceae. This group of algae and the molecular markers used in the zygnematophytes' molecular phylogeny will be presented in this thesis. Zygnematophytes have unicellular or multicellular forms and they generally occur in freshwater habitats. Desmids are useful as indicators of water quality and they are also used for scoring of conservation value. Therefore it is important to have the species well defined. The confusion in defining of desmid species was caused by often very variable morphology. Some authors had different opinions on the classifying of desmid species and theirs subunits. The combination of molecular phylogeny, electron microscopy and geometric morphometrics was used in revealing of (pseudo)cryptic species in the genera Micrasterias or Xanthidium. The geometic morphometrics was helpful for finding of important details for distinguishing of particular pseudocryptic species. Key words: cryptic and pseudocryptic diversity, conjugation, desmids, Micrasterias, Euastrum, Xanthidium, molecular phylogeny, taxonomy, geometric morphometrics, biogeography, green algae
|
|
|
Shape variability of diatom frustules during the life cycle.
Woodard, Kateřina ; Kulichová, Jana (advisor) ; Kleisner, Karel (referee)
The determination of diatom species is mostly based on morphology of a silicified cell wall. It is complicated by the fact of cell diminution during the vegetative phase of the life cycle, which is conected with shape changes and loss of some taxonomically importat characters. Even though the diminution during the life cycle is generally known phenomeon, there is a lack of studies on this theme. In this masters thesis, four monoclonal populations of model pennate diatom strains were used in order to study shape dynamics during the life cycle. The strains were cultivated for almost three years and parts of the cultures with a different size stages were fixed in permanent preparations. The digital photographs of the cells were used as a material for the geometric morphometrics analyses. The study revealed high contribution of significant allometric changes to an overall shape variability. During the vegetative phase of the life cycle, disparity of the cells increases and complexity of the cells decreases. The contribution of symetric variability to an overall shape variability is more than eighty percent. Phenotypic plasticity in a monoclonal populations is an interesting finding from an evolutionary point of view. It may indicate constraints caused by the silica cell wall. During the size diminution...
|
guest ::
