Climate change is expected to have a strong impact on subarctic ecosystems. Increased temperatures as well as altered precipitation and snow cover patterns are predicted to change species distribution and affect biogeochemical processes in the subarctic tundra. Bryophytes are an essential vegetational component in northern ecosystems, due to their high abundance and importance in many ecological processes. In this study the effects of elevation and altered snow cover on the temporal dynamics of freezing damage in three subarctic bryophyte species (Hylocomium splendens, Ptilidium ciliare, and Sphagnum fuscum) were studied in a snow manipulation field experiment in Abisko, during early spring. Soil temperature and field moisture of moss shoots were collected. A freeze-thaw incubation experiment was conducted to investigate the freeze-thaw cycle resistance of H. splendens and P. ciliare originating from habitats with two differing snow-cover thicknesses. Freezing damage differed significantly between the bryophytes species with P. ciliare experiencing the least and S. fuscum the highest damage. Damage was higher at the low elevation, possibly attributable to acclimation effects. Snow removal led to higher damage in moss shoots, but no interactions of the different snow cover treatments with elevation, species or time were found. Freezing damage increased over time and no recovery occurred, likely due to temporal patterns in soil freeze-thaw cycles during early spring. Soil freeze-thaw cycles were the main factor influencing damage in bryophytes after snow melt. Measured environmental parameters could not explain the entire variation in damage. Damage might additionally be attributable to increased UV radiation or disturbances by herbivores.

The aim of this thesis was to carry out an analysis of primary school textbooks considering bryophytes and bracken, as well as to plan a biological excursion in the area of Dolský Mlýn which would include mapping the terrain. The sixth chapter contains the analysis of nine textbooks from different publishing houses. I have compared them in terms of the number of pages dedicated to bryophytes and bracken and in terms of the number of stated bryophytes and bracken representatives. I have also compared whether the textbooks are provided by workbooks, methodological guides and other material, which could variegate biology and natural history teaching. The seventh chapter characterises the location. Mapping of the terrain for the planned excursion took place in September 2012. I chose fourteen suitable sites which are were easily accessible. The eight chapter includes methodical instructions of the excursion for teachers, worklists and the key to determining types of bryophytes. The practical verification of my thesis took place in April 2013 during an excursion of seventh grade pupils from the school ZŠ a MŠ Děčín IV. Laboratory training, which represents an integral part of the excursion took place in March due to unfavorable chmate conditions. Pupils determined mosses of genus Merike according to their...

3 ABSTRACT More than 30 % of agricultural land in Europe also Czech Republic is covered by arable fields. There is no evidence about diversity of some arable fields bounded species groups. In general the diversity of arable land species is less than the wild land species. For increasing species diversity in agricultural land European commission comes up with agri environmental farming schemes in 90's. Till now real effectiveness of the agri environmental schemes is not clear for all species groups. In my thesis I have investigated whether the diversity and community composition of arable bryophytes species is influenced by agri environmental or conventional management on cereal fields. The influence of agri environmental management on arable bryophytes was never investigated in Europe unlike the other species groups like vascular plants, non vertebrates or vertebrates. The thesis stands on dataset provided by Ministry of agriculture for 3 Czech regions (kraj Vyso ina, Pardubický kraj, St edo eský kraj). My own research of arable bryophytes diversity held on 12 fields within 6 localities is the main part of the thesis supplemented by basic soil measurements and climatic characteristics extractions. Main result of the thesis is finding that conventional management has marginally positive effect on arable...

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Mosses display a number of hallmark life history traits that influence their ecology at the population and community level. The long lived separation of sexes observed in the haploid gametophyte (dioicy) is one such feature of particular importance, as it is observed in the majority of bryophytes and creates intraspecific specialization of male and female individuals. The prevalence of sexually dimorphic mosses raises the possibility of sex-specific interactions with fungi as observed in some vascular plants. Here I investigated how moss sex shapes fungal communities associated with gametophytic tissues of the ubiquitous moss, Ceratodon purpureus. Using greenhouse populations of C. purpureus grown in a common garden, I examined fungal community structure and overall abundance of fungal biomass associated with male and female individuals from multiple populations. I hypothesized that individual mosses would harbor unique fungal communities based on their sex, and that overall fungal biomass associated with host tissues would differ significantly due to differences in morphological and physiological characteristics between the sexes. I found that fungal community composition and overall abundance (i.e. biomass) differ between male and female individuals of C. purpureus, and that sex-specific patterns are retained across individuals from three different populations. This work provides a first glance at how genetically based sexual systems in early land plants influence affiliated fungal community composition.

Die Wälder Mitteleuropas wurden seit dem Neolithikum stark durch den Menschen beinflusst. Die meisten Wälder weisen keine naturnahe Struktur mehr auf, es fehlen große, alte Bäume ebenso wie stehendes und liegendes Totholz. Die Fortwirtschaft lässt die Herausbildung später Entwicklungsphasen mit alternden und absterbenden, zusammenbrechenden Baumindividuen nicht zu. Zahlreiche Studien haben jedoch die Bedeutung alter und zerfallender Waldbestände für spezialisierte Waldorganismen gezeigt. Die vorliegende Studie beabsichtigte, die Bedeutung der späten Sukzessions-Stadien für die Pflanzendiversität im Rahmen der natürlichen Dynamik eines unbewirtschafteten Fichtenwaldes (Picea abies (L.) Karst.) auf dem Brocken in Norddeutschland herauszustellen. Zusätzliche Untersuchungen behandelten die Autökologie epiphytischer Flechten in einer naturnahen, wenig belasteten Waldumgebung und das Potenzial alter und zerfallender Waldstadien für die Speicherung von Kohlenstoff. Die verschiedenen Untersuchungen bauen auf Plot-basierte Erhebungen in den verschiedenen Waldentwicklungsstadien auf, und bezogen dabei sowohl die Epiphyten- als auch die Bodenvegetation ein. Die Ergebnisse zeigen eindeutig die Bedeutung der späten Wald-Sukzessionsstadien für die Diversität von Epiphyten. Während die Artenvielfalt der Epiphyten in Alters- und Zerfallsstadien höher war als in jüngeren Sukzessionsstadien, unterschied sich die Bodenvegetation kaum zwischen den verschiedenen Sukzessionsstadien. Weiterhin unterschied sich die Zusammensetzung der Epiphytenvegetation im Zerfallsstadium deutlich von allen übrigen Stadien. Einige seltene Arten kamen vorwiegend auf den abgestorbenen Bäumen der Zerfallstadien vor. Hier entstehen große stehende und liegende Totholzobjekte, die auch in jüngeren Entwicklungsstadien erhalten bleiben (‚deadwood legacy’), und über den gesamten Waldentwicklungszyklus die Epiphytenansiedelung auf Bäumen ermöglichen. Es zeigte sich auch, die Präsenz alter und abgestorbener Bäume wichtiger war als die Kontinuität in der Waldbedeckung. Die Vegetation des studierten Urwaldes und eines benachbarten Sekundärwaldes, die beide viele alte und tote Bäume aufwiesen, hatten sich innerhalb von 200 Jahren stark angenähert. Untersuchungen der Vegetation des liegenden Totholzes bestätigten einen starken Einfluss der Substrateigenschaften Stammgröße und Holz-Zerfallsgrad. Der Kronenschlussgrad der Waldbestände hatte hingegen einen geringeren Einfluss. Totholz hat eine hohe Bedeutung für die Waldpflanzen-Diversität. Viele seltene Arten wuchsen ausschließlich auf liegendem Totholz, während viele häufige Arten, neben anderen Substraten, ebenfalls auf Totholz vorkamen. Während kleine Totholzobjekte kaum besiedelt wurden, beherbergten große Totholzobjekte eine artenreichere Epiphytenvegetation. Die höchste Epiphytendiversität wurde jenseits mittlerer Zerfallsgrade erreicht. Zusätzliche Untersuchungen von epiphytischen Flechten zeigten einen extremen Rückgang der acidophytischen Flechte Lecanora conizaeoides bei einer leichten Erhöhung des pH-Wertes der Baumrinden. Zudem zeigte sich, dass die Artenvielfalt der Epiphyten sich weniger zwischen lebenden und abgestorbenen Bäumen unterschied, als es unter höherer Luftverschmutzung. Zusätzlich wiesen biochemische Analysen der Flechten Hypogymnia physodes einen hohen Gehalt an Flechtenstoffen nach, die auch bei geringer Umweltbelastung die Aufnahme von Schwermetallen regulieren. Auch hier waren nur geringe Unterschiede zwischen den Proben von den verschiedenen lebenden und abgestorbenen Bäumen festzustellen. Es wurde außerdem nachgewiesen, dass die Alters- und Zerfallsstadien sich durch eine hohe Kohlenstoffspeicherung in Boden und Biomasse auszeichnen. Zusammen mit den Ergebnissen zur Pflanzendiversität, der Bedeutung der großen Totholz-Objekte sowie alter und abgestorbener Bäume, wurde die Bedeutung der Alters- und Zerfallsstadien klar bestätigt. Schutzmaßnahmen, die auf den Ausschluss der Bewirtschaftung großer Waldgebiete abzielen und damit die natürliche Herausbildung der Alters- und Zerfallsstadien zulassen, können sicher einen Rückgang der Biodiversität begrenzen und die Folgen des globalen Klimawandels abmildern.

In this study adaptations of bryophytes and lichens to desiccation stress were examined. The aim was to test whether desiccation tolerance in the selected species is constitutive or if desiccation tolerance could be induced by various hardening treatments. In addition, some putative tolerance mechanisms were investigated, including the accumulation of sugars, increase in ROS scavenging systems and other mechanisms e.g. energy dissipating processes. To determine if hardening treatments prior to desiccation stress increased desiccation tolerance, mosses and lichens were partially desiccated or treated with ABA. The effect of hardening treatments on the physiology of the moss Atrichum androgynum and lichens Peltigera polydactyla, Ramalina celastri and Telochistes capensis during a desiccation-rehydration cycle was investigated. Photosynthesis, respiration and chlorophyll fluorescence measurements were used as rapid tools to determine the metabolic activities in these lichens and moss species. In A. androgynum partial desiccation following slow drying at 52% RH increased the rate of recovery of net photosynthesis. Net photosynthesis recovered almost completely following slow drying in the material that was partially dehydrated and/or treated with ABA. This suggests that partial dehydration hardens the moss, and that ABA can fully substitute for partial dehydration. In R celastri and P. polydactyla both partial dehydration and ABA treatments displayed some improvement in desiccation tolerance depending on the duration and severity of stress. The reduction in the re-saturation respiration burst in P. polydactyla, although not quite significant, strongly suggests that hardening increases mycobiont tolerance. However, it is more difficult to establish whether the hardening treatments improve photobiont performance. In the moss A. androgynum ABA treatment increased the rate of recovery of photosynthesis and PSII activity, and also doubled non-photochemical quenching (NPQ). Increased NPQ activity will reduce ROS formation, and may explain in part how ABA hardens the moss to desiccation. In ABA treated, but not untreated mosses, desiccation significantly increased the concentration of soluble sugars in A. androgynum. Sugar accumulation may promote vitrification of the cytoplasm and protect membranes during desiccation. Starch concentrations in freshly collected A. androgynum and R. celastri were only c. 40 and 80 mg g ¯¹ dry mass respectively, and slightly rose during desiccation, but were only slightly affected by ABA pretreatment. ABA did not reduce chlorophyll breakdown during desiccation. In P. polydactyla ABA pretreatment had little effect on any of these parameters. Changes in the activities of the free radical scavenging enzymes ascorbate peroxidase, catalase and superoxide dismutase were measured during wetting and drying cycles in the moss A. androgynum and in the lichens P. polydactyla, R. celastri and T capensis. These species normally grow in the understorey of the Afromontane forest, moist, xeric, and extremely xeric miicrohabitats respectively. In A. androgyum, enzyme activity was measured shortly after collection, after 3 d storage following hardening by partial dehydration and/or 1 h treatment with ABA or distilled water and during desiccation and rehydration. In A. androgynum enzyme activities of CAT and SOD in untreated material were always higher than in the hardened treatments, while both partial dehydration and ABA treatments tended to reduce both CAT and the induction of SOD activity, although these effects were not significant between the treatments. This suggests that ABA may not be involved in the induction of free radical scavenging enzymes and probably these enzymes are not important in desiccation tolerance of A. androgynum. In lichens, the enzyme activity was measured shortly after collection, after hydration for 48 hat 100% RH, after desiccation for 14 d and 28 d, and during the first 30 min of hydration with liquid water. Enzyme activities tended to rise or stay the same following rehydration in all the species tested. After desiccation for 14 d, enzyme activities decreased, and then decreased further to very low values after 4 weeks desiccation. In all species, including T capensis from an extremely xeric habitat, the activities of all enzymes remained at very low values during the 30 min following rehydration, and were therefore unavailable to remove any reactive oxygen species accumulating in lichen tissues as a result of desiccation. Results suggests that the enzymic antioxidants are more likely to be involved in removing reactive oxygen species produced during the normal metabolic processes of lichens than having a role in desiccation tolerance. The Afromontane understorey moss Atrichum androgynum displayed an oxidative burst of H₂O₂ during rehydration following desiccation. Maximum rates of H₂O₂ production occur during the first 15 min of rehydration. While the production of H₂O₂ increases with increasing desiccation times, the moss produced significant amounts of H₂O₂ during rehydration after desiccation for times that did not inhibit photosynthesis or cause K⁺ leakage. A. androgynum may produce more H₂O₂ during desiccation than rehydration, because desiccation artificially induced using polyethylene glycol strongly stimulates production. Experiments involving inhibitors and exogenously supplied reductants indicate that peroxidases are responsible for the synthesis of H₂O₂. Factors that influence the rate of H₂O₂ production during rehydration include light and the hormone ABA. Patterns of H₂O₂ production are discussed in terms of their possible role as a defence against pathogenic fungi and bacteria. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 2002.

Thesis (doctoral)--Swedish University of Agricultural Sciences, 2008. / Thesis documentation sheet inserted. Includes appendix of reprints of five papers and manuscripts co-authored with others. Includes bibliographical references. Also partially issued electronically via World Wide Web in PDF format; online version lacks appendix of papers.

Thesis (doctoral)--Swedish University of Agricultural Sciences, 2000. / Chiefly consists of 4 journal article manuscripts, 2 co-authored with other writers. Thesis documentation sheet inserted. Includes bibliographical references. Also partially available electronically via World Wide Web in PDF format; online version lacks appendix of article manuscripts.

This study focused on the primary cell wall constituents and plasmodesmata (PD) density in three mosses and four liverwort apical cells (AC) and immediate derivatives. The three mosses have tetrahedral apical cells and the liverworts possess tetrahedral, hemidiscoid and lenticular AC geometries. The primary cell wall in the studied taxa is comprised of two layers. A fibrillar layer, which is the outer wall layer, contains compacted cellulosic fibrils, and represents the two adjacent primary walls and middle lamella, the latter of which is rarely discernible. An electron-lucent inner wall layer abuts the plasma membrane. This layer has faint fibrous materials that extend from the plasma membrane to the fibrillar layer. Generally, as the cell wall ages it thickens, the fibrillar layer increases in width while the electron-lucent wall stays more or less consistent in width. In the four liverworts, the most recent wall of the AC has the highest PD density in the apical region regardless of AC geometry. As the walls elongate, primary wall is laid down between PD, separating them and resulting in lower densities and wider PD diameters in older walls. The season of fixation and whether plants were studied from nature or culture have an influence on AC ultrastructure. A developmental study of Physcomitrella patents gametophores in four stages, bud, 2-leaved, 7-8-leaved and ~20-leaved, reveals that the primary cell wall constituents change slightly during development. Specifically, LM5 a RG-I pectin antibody against the galactan branch epitope is only localized in the fibrillar layer of young water-conducting cells in the 7-8-leaved and 20-leaved gametophores. LM20, an antibody against HG esterified pectins, does not localize in any of the cell walls during development. The distribution patterns for AGPs (JIM13 and LM2) are consistent during gametophore development and predominantly localize on the electron-lucent layer and wall/plasma membrane interface. However, LM2 is mainly localized on the fibrillar layer in 7-8-leaved cell walls. AGPs also localize on element of the cytoplasm. LM6, an antibody against an RG-I pectin with arabinan branch epitopes, also localizes AGPs and because it expressed similar distribution patterns as JIM13 and LM2 on the cell wall, it likely localizes AGP in Physcomitrella. In addition, LM6 localizes pectins on the fibrillar layer similar to LM5 and LM19 for HG unesterified pectins. Callose predominantly localizes at the PD neck region. This study provides the first documentation of changes in size and shape of AC with age in Physcomitrella patens gametophores. The PD densities of gametophytes examined in this study fall into the lineage-specific network of PD (LPD) group designated for sporophytes of monilophytes and Selaginella (heterosporous lycophyte) with single ACs. Takakia lepidozioides leafy shoot has a tetrahedral AC with a highly curved free surface. This peculiar moss has mucilage hair (MH) associated with axil of phyllids. Mucilage hair in both species are 3-celled with a forth epidermal cell as the base. However, occasional 2-celled MH is seen in T. ceratophylla. The ultrastructure of MH has similarities with other mosses and liverworts.