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Fissidens macrosporus Dixon, a poorly known species from the Western Ghats of India, was recollected after more than 90 years. It belongs to subgenus Aloma.
Bryophytes with indeterminate growth rarely exhibit clearly identifiable modules or age segments, but can be vertically divided into different physiologically active zones, since physiological activity normally declines vertically along the shoot profile depth. The aim of this study was to investigate whether it is possible to use C:N ratios (C/N) and/or parameters from chlorophyll fluorescence measurements (e.g. Fv/Fm, Fm or qN) to determine if bryophyte tissue is alive, senescent or dead, and at what distance along the shoot segment profile the moss tissue cease to live. Variation in C:N ratios and chlorophyll fluorescence between sites was also examined. This study shows that it is possible to separate alive, senescing and dead parts of the moss shoots in Pleurozium schreberi, and that chlorophyll fluorescence is a good method to use, whereas C/N varies between sites and species (for Hylcomium splendens and Racomitriumlanuginosum) and does not seem to reflect physiological activity to the same degree.
This work demonstrates mosses and liverworts are able to freeze water at elevated temperatures. They are likely to do this as a means of harvesting additional water by the Bergeron—Findeisen process and as a consequence potentially influence atmospheric processes.
The conditions at the first Swedish and mainland European Campylium longicuspis locality are described and compared with the few so far reported finds of this species. The species appears to prefer chiefly calcium-rich wetland habitats. Campylium longicuspis is mainly Arctic, and a map of its known distribution is presented.
The moss Calliergon megalophyllum is rediscovered in the Netherlands after approximately 50 years of absence, in a location different from before: National Park Weerribben-Wieden. This is a Natura 2000 wetland area, and a Dutch hotspot for rich-fen bryophytes. The species was growing in a fen pool. Plant species composition and water chemistry were compared with Swedish samples collected throughout the country. Water chemistry of C. megalophyllum in Sweden was also compared with four other (semi-)aquatic species: C. giganteum, Scorpidium scorpioides,Sarmentypnum trichophyllum and S. exannulatum. The species is characteristic for poorly buffered habitats, but has nevertheless relatively high pH, which makes it sensitive to acidification, especially when atmospheric deposition is high. In the Dutch locality, buffer capacity is maintained by input of base-rich ditch water through small channels in the fen. The data further suggest that, like other Calliergon species, C. megalophyllum is growing in relatively nutrient-rich habitats, especially with respect to P and K. In the Netherlands, plant nutrient concentrations suggest that P is indeed not limiting, which may enhance survival of the species, as P-poor habitats in this country have become very rare.
Porella obtusata is a liverwort with a southwestern distribution in Europe. In Norway it is confined to areas with oceanic climate along the west coast, where it also reaches its northern limit. Typically it is growing on sunlit, base rich rocks at sea level in southwestern Norway, a scarce habitat in these coasts dominated by granitic bedrock. There are some old records, but investigations after year 2000 have yielded much new information. Porella obtusata is a rare species in Norway, and the new information shows that its habitat is threatened by exploitation and shrub encroachment of the shoreline.
Ice nucleation has previously been described in only a few lichens from a single location. Here we greatly extend this work and suggest that in lichens ice nucleation is a water harvesting adaption. Fifty-seven lichen samples from a variety of widespread locations were tested for ice nucleation by differential scanning calorimetry (DSC). Samples initiated freezing in the range -5.1° to -20°C and the median freezing temperature was -7.2°C. The vapour pressure difference between ice and water is significant at this temperature, and so ice grows at the expense of water (Bergeron—Findeisen process). Therefore, the ability to form ice at these temperatures provides a useful water-harvesting mechanism for lichens. Ice nucleation appears to be ubiquitous in lichens and is more likely to be associated with the mycobiont and may influence atmospheric processes.
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