Microorganisms of Biological Crusts on Soil Surfaces

Büdel, Burkhard

doi:10.1007/3-540-26609-7_15

Cited by 24 publications

(17 citation statements)

References 37 publications

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“…Klebsormidium is a diverse genus containing aquatic species as well as species that participate in soil algal communities that regularly experience dramatic desiccation (Ettl and Gärtner 1995;Büdel 2005). Several Klebsormidium sp.…”

Section: Discussionmentioning

confidence: 99%

Plasmolysis effects and osmotic potential of two phylogenetically distinct alpine strains of Klebsormidium (Streptophyta)

et al. 2011

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The osmotic potential and effects of plasmolysis were investigated in two different Klebsormidium strains from alpine habitats by incubation in 300-2,000 (3,000) mM sorbitol. Several members of this genus were previously found to tolerate desiccation in the vegetative state yet information was lacking on the osmotic potentials of these algae. The strains were morphologically determined as Klebsormidium crenulatum and Klebsormidium nitens. These species belong to distinct clades, as verified by phylogenetic analysis of the rbcL gene. K. crenulatum is part of to the K. crenulatum/mucosum ('F' clade) and K. nitens of the 'E2' clade. Plasmolysis occurred in K. crenulatum at 800 mM sorbitol (961 mOsmol kg(-1), Ψ = -2.09 MPa) and in K. nitens at 600 mM sorbitol (720 mOsmol kg(-1), Ψ = -1.67 MPa). These are extraordinarily high osmotic values (very negative osmotic potentials) compared with values reported for other green algae. In K. crenulatum, the maximum photosynthetic rate (Pmax) in the light-saturated range was 116 μmol O(2) h(-1) mg(-1) chl a. Incubation in 1,000 mM sorbitol decreased Pmax to 74.1% of the initial value, whereas 2,000 mM sorbitol (Ψ = -5.87 MPa) lead to an almost complete loss of oxygen production. In K. nitens, Pmax was 91 μmol O(2) h(-1) mg(-1) chl a under control conditions and incubation in 800 mM sorbitol did not decrease Pmax, 2,000 mM sorbitol decreased Pmax only to about 62.6% of the initial value whereas 3,000 mM sorbitol stopped oxygen evolution. This indicated a broader amplitude for photosynthesis in the examined strain of K. nitens. Control samples and samples plasmolysed for 3 h in 800 mM sorbitol (K. nitens), 1,000 mM sorbitol (K. crenulatum), or 2,000 mM sorbitol were investigated by transmission electron microscopy after chemical or high-pressure freeze fixation. In cells undergoing plasmolysis the protoplasts were retracted from the cell wall, the cytoplasm appeared dense, vacuoles were small and fragmented, and the cytoplasm was filled with ribosomes. Thin cytoplasmic strands were connected to the cell wall; 2,000 mM sorbitol increased the effect. The content of soluble carbohydrates in these two strains was investigated by HPLC, as this is one known mechanism for cells to maintain high osmotic pressure of the cytosol. Both Klebsormidium species contained diverse soluble carbohydrates, including a dominant mixed peak of unidentified oligosaccharides, and more minor amounts of raffinose, sucrose, glucose, xylose, galactose, mannose, inositol, fructose, glycerol, mannitol, and sorbitol. The total content of soluble carbohydrates was approximately 1.2% of the dry weight, indicating that this is not a major factor contributing to the high osmotic potential in these strains of Klebsormidium.

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Section: Discussionmentioning

confidence: 99%

Plasmolysis effects and osmotic potential of two phylogenetically distinct alpine strains of Klebsormidium (Streptophyta)

et al. 2011

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“…They participate in symbiotic associations with fungi, forming lichens (e.g. Trebouxia; Friedl, 1997), or grow on (and partly in) various natural surfaces such as the bark of trees, rocks and soil (Bell, 1993;Belnap & Lange, 2001;Johansen & Shubert, 2001;Bu¨del, 2005;Cardon et al, 2008, and references therein). In urban areas, extensive growth on man-made surfaces such as roof tiles, building facades and concrete pathways may become a biofouling problem Eggert et al, 2006;Karsten et al, 2007b).…”

Section: Introductionmentioning

confidence: 99%

Ecophysiological performance of an urban strain of the aeroterrestrial green algaKlebsormidiumsp. (Klebsormidiales, Klebsormidiophyceae)

Karsten

Rindi

2010

European Journal of Phycology

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Aeroterrestrial green algae are among the most ubiquitous members of the microbial flora colonizing aerial surfaces. Filamentous green algae, in particular, produce large populations in several natural and artificial habitats. In recent years it has been shown that the bases of the walls of urban environments are frequently colonized by filamentous green algae. However, information concerning the physiology of these organisms and the factors that determine their distribution is extremely limited. We studied the physiological responses of a strain of Klebsormidium sp. (Klebsormidiales, Klebsormidiophyceae) collected in an urban area (Konstanz, Germany). Growth responses, photosynthetic performance, desiccation tolerance and accumulation of organic osmolytes were measured in several different combinations of environmental factors. Klebsormidium sp. exhibited optimal growth and highest photosynthetic efficiency under relatively low photon fluence rates, performing optimally between 15 and 30 mmol photons m À2 s À1 and showing increasing inhibition above 85 mmol photons m À2 s À1. Although it could survive at salinities up to 60 psu, this alga was relatively stenohaline; growth was optimal between 1.2 and 15 psu and declined considerably at higher salinities. Sucrose acted as the major organic osmolyte, and its concentration increased almost linearly between 1.2 and 30 psu from 29.7 to 171.2 mmol g À1 dry weight. Further increases in salinity, however, were accompanied by a strong reduction in sucrose content pointing to insufficient osmotic adjustment. Klebsormidium sp. was able to photosynthesize efficiently for up to 2 hours under complete desiccation. Afterwards, however, there was no measurable photosynthetic activity although complete photosynthetic efficiency (F v /F m ) was recovered upon rehydration for 48 hours. Overall, the results correlate well with the ecology of Klebsormidium sp. in the field and its distribution in continental Europe.

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“…Although many BSC from subtropical to Polar Regions have been described in recent decades (Belnap & Lange, 2003;Türk & Gärtner, 2003;Büdel, 2005;Karsten & Holzinger, 2014) little is known of tropical BSCs. It is remarkable that in Peru there are no previous studies on the BSC.…”

Section: Perspectives For Future Bsc Research In Perumentioning

confidence: 99%