In:
Functional Plant Biology, CSIRO Publishing, Vol. 27, No. 5 ( 2000), p. 379-
Abstract:
Tolerance of desiccation was examined in three
species of moss, Grimmia antarctici Card., Ceratodon purpureus (Hedw.) Brid. and
Bryum pseudotriquetrum (Hedw.) Gaertn., Meyer et Scherb. collected from two sites of contrasting water availability in the Windmill
Islands, continental Antarctica. Physiological tolerance to desiccation was measured using chlorophyll fluorescence in plugs of moss during natural drying
in the laboratory. Differences in relative water content, rate of drying and the response of photosynthesis to desiccation were observed among the three
species and between sites. Of the three species studied, G. antarctici showed the lowest capacity to sustain
photosynthetic processes during desiccation, B. pseudotriquetrum had an intermediate response and
showed the greatest plasticity and C. purpureus showed the greatest capacity to sustain photosynthesis during desiccation. These
results fit well with the known distribution of the three species with G. antarctici being limited to relatively wet sites,
C. purpureus being common in the driest sites and B. pseudotriquetrum showing a wide distribution between
these two extremes. Levels of soluble carbohydrates were also measured in these samples following desiccation and these indicate the presence of
stachyose, an oligosaccharide known to be important in desiccation tolerance in seeds, in B. pseudotriquetrum. Both gross morphology
and carbohydrate content are likely to contribute to differences in desiccation tolerance of the moss species. These results indicate that if the
Casey region continues to dry out, as a result of local geological uplifting or global climate change, we would expect to see not only reductions in the
moss community but also changes in community composition. G. antarctici is likely to become more limited in
distribution as C. purpureus and B. pseudotriquetrum expand into drying areas.
Type of Medium:
Online Resource
ISSN:
1445-4408
Language:
English
Publisher:
CSIRO Publishing
Publication Date:
2000
SSG:
12
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