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Freeze avoidance: a dehydrating moss gathers no ice
Author(s) -
LENNÉ THOMAS,
BRYANT GARY,
HOCART CHARLES H.,
HUANG CHENG X.,
BALL MARILYN C.
Publication year - 2010
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/j.1365-3040.2010.02178.x
Subject(s) - moss , dehydration , desiccation , ice nucleus , sugar , differential scanning calorimetry , botany , parenchyma , biophysics , biology , horticulture , chemistry , nucleation , food science , biochemistry , physics , organic chemistry , thermodynamics
Using cryo‐SEM with EDX fundamental structural and mechanical properties of the moss Ceratodon purpureus (Hedw.) Brid. were studied in relation to tolerance of freezing temperatures. In contrast to more complex plants, no ice accumulated within the moss during the freezing event. External ice induced desiccation with the response being a function of cell type; water‐filled hydroid cells cavitated and were embolized at −4 °C while parenchyma cells of the inner cortex exhibited cytorrhysis, decreasing to ∼20% of their original volume at a nadir temperature of −20 °C. Chlorophyll fluorescence showed that these winter acclimated mosses displayed no evidence of damage after thawing from −20 °C while GCMS showed that sugar concentrations were not sufficient to confer this level of freezing tolerance. In addition, differential scanning calorimetry showed internal ice nucleation occurred in hydrated moss at ∼−12 °C while desiccated moss showed no evidence of freezing with lowering of nadir temperature to −20 °C. Therefore the rapid dehydration of the moss provides an elegantly simple solution to the problem of freezing; remove that which freezes.