Pflanzenökologie & Systematik
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Pflanzenökologie & Systematik
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Ökophysiologie
von Cyanobakterien, Algen, Flechten und Bryophyten -
Ecophysiology of Cyanobacteria, Algae, Lichens & Bryophytes |
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Prof.
Dr. Burkhard Büdel, Dr. Bettina Weber, Dr. Michael Lakatos
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Die Ökologie und mehr noch die physiologische Ökologie beschäftigt sich mit den kausalen (ursächlichen) Zusammenhängen von Verbreitungsmustern der Pflanzen und pflanzenähnlichen Organismen, mit deren Bau und ihren spezifischen physiologischen Leistungen. Als Maß der Vitalität benutzen wir in den meisten Fällen die Assimilationsleistung und daraus resultierend den Kohlenstoffgewinn unter natürlichen und unter Laborbedingungen. Darüber hinaus wird in diesem Zusammenhang die Verbindung zwischen Bau und Funktion (funktionelle Morphologie und Anatomie) untersucht, womit eine Rückkopplung zur Systematischen Forschung geschaffen wird. |
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Ecology
and even more physiological ecology deal with causal relationships
of plant and plantlike organism distribution patterns, with their structure,
and their specific physiological capacities. Assimilation efficiency and
resulting carbon gain under natural and lab conditions is used as a measure
of vitality. Furthermore, the accociation between structure and function
(functional morphology and anatomy) is analyzed, providing a feedback
to systematic studies.
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Forschungsprojekte
- Research Topics
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Bettina Weber, Burkhard Büdel: Biogenic weathering patterns caused by endolithic cyanobacteria and lichens |
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Michael Lakatos: Funktionelle Ökologie mikrobieller Krusten in humiden Ökosystemen - Functional Ecology of non-vascular phototrophs |
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Tanja Lakatos: Biodiversität und Funktionalität epiphytischer autotropher Mikroorganismen in Kronenraumsystemen - Biodiversity and functionality of epiphytic autotrophic microorganisms in forest canopies |
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Burkhard Büdel: Morphologie der Flechten beeinflusst Photosyntheseleistung und Wasserhaushalt - Growth form of lichens determines photosynthetic rates and water balance |
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Holger Thüs : Ökophysiologie aquatischer Flechten und ihrer isolierten Phycobionten - Ecophysiology of aquatic lichens and their isolated phycobionts |
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Biogenic
weathering patterns caused by endolithic cyanobacteria and lichens
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Biogenic weathering patterns are well known from lichens and cyanobacteria. They could be divided into mechanical and chemical processes, that are caused by the organisms. Up to now, the effects of acidification were described as the only chemical weathering process. However, we now could proof, that endolithic cyanobacteria (i. e. cyanobacteria, that live inside the rock) cause an exfoliative weathering process of sandstone by alkalization of the substrate (Fig. 1 A, B, from Büdel et al., 2005). In geological thin sections, it could be shown, that in the noncolonized sandstone from underneath the cyanobacterial community, the quartz grains are round and do not show weathering cavities (Fig. 2 A, Cementing material indicated by arrows). In the growth zone of the organisms, the binding material was dissolved, silicate grains of the substrate were etched and instead, fine grains of calcium carbonate had precipitated (Fig. 2 B, yellow arrows indicate erosive cavities, red arrow shows precipitated carbonate). In cultures of the organisms, it could be shown, that the alkalization process is photosynthesis dependent. The effects of organisms on the substrate are also studied for endolithic lichens and Biological Soil Crusts. For more information regarding this topic, see publication Büdel et al. 2005. |
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Fig. 1 A: Close-up of the surface of a Tshipise sandstone outcrop (Langjan Nature Reserve, Limpopo Province, South Africa), showing scaled off rock chips and the blue-green colour of the cryptoendolithic cyanobacteria. In the central part of the picture, the upper layer of the rock was removed with hammer and chisel. |
Fig. 1 B: Cross-fractured rock piece, surface on top. The green band of the cyanobacterial community is located 1-2 mm underneath the surface. From Büdel et al., 2005 |
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Fig. 2, A and B: Petrographic
thin sections and SEM micrographs of Tshipise sandstone. |
2 B) Cross-section of the layer colonized by cyanobacteria; yellow arrows indicate erosive cavities, whereas red arrow shows precipitated carbonates (golden colour). From Büdel et al., 2005 |
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Morphologie
der Flechten beeinflusst Photosyntheseleistung und Wasserhaushalt:
am Beispiel von 3 Wuchsformen der Gattung Peltula - Growth form of lichens determines photosynthetic rates and water balance: as example 3 growth forms of the genus Peltula |
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Die Gattung Peltula wird hier in 3 verschiedenen Wuchsformen vorgestellt: 1) die krustose-squamulose Form wie z.B. bei Peltula umbilicata, 2) die peltate (schildartige) Form wie z.B. bei Peltula euploca und 3) die semifrutikose Form wie bei Peltula tortuosa (Abb. 2). Arten der Gattung Peltula kommen weltweit auf exponierten Felsoberflächen vor. Der Cyanobiont dieser Flechte ist in den meisten Fällen das Cyanobakterium Chroococcidiopsis. Trotz dieses gemeinsamen Cyanobionten ist das photosynthetische Verhalten in Bezug zum Wassergehalt sehr unterschiedlich (Abb. 1). |
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The
genus Peltula is presented in 3 different growth forms: 1) crustose-squamulose
form, e.g. Peltula umbilicata, 2) peltate form (shield like), e.g.
Peltula euploca and 3) semifruticose form, e.g. Peltula tortuosa
(Fig. 2). Species of this genus occur worldwide on
exposed rock surfaces. With the unicellular cyanobacterium Chroococcidiopsis,
most of them posses the same cyanobiont. Although sharing the same cyanobiont,
their photosynthetic behavior is quite different in response to water
content (Fig. 1).
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Abb.
1: Vergleich des photosynthetischen Verhaltens in Bezug zum Wassergehalt
bei Dermatiscum thunbergii, Peltula umbilicata, Peltula
euploca und Peltula tortuosa
Fig. 2: Comparison of the photosynthetic behavior in response to water
content for Dermatiscum thunbergii, Peltula umbilicata,
Peltula euploca and Peltula tortuosa
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Abb. 2: Die individuelle maximale Gaswechselrate bei einem bestimmten Wassergehalt des Thallus variiert eindeutig mit der arteigenen Wuchsform der Flechte. Fig. 2: The individual maximum gas exchange rates at a certain thallus water content clearly varies with the specific growth form of the lichen. |
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Abb. 3: Das hohle Mark dieser Flechten enthält immer Luft und ist unter Umweltbedingungen nie mit Wasser gefüllt (LTSEM) Fig. 3: The hollow medulla of these lichens always contains air and never is filled with water under environmental conditions (LTSEM) |
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