Effects of freezing and cold acclimation on the plasma membrane of isolated protoplasts

Technical Report · Tue Jan 01 00:00:00 EST 1991

OSTI ID:5840280

Steponkus, P L

The principal goal of our program is to provide a mechanistic understanding of the cellular and molecular aspects of freezing injury and cold acclimation from a perspective of the structural and functional integrity of the plasma membrane -- the primary site of freezing injury in winter cereals. Our immediate goals are (1) to provide an understanding of the mechanism by which freeze-induced dehydration affects the formation of aparticulate domains and lamellar-to-hexagonal{sub {parallel}} phase transitions in the plasma membrane of NA protoplasts, (2) to characterize the cellular and molecular mechanisms by which cold acclimation and cryoprotectants preclude or diminish these alterations in the plasma membrane of ACC protoplasts and (3) to elucidate the molecular basis for the lesion that limits the maximum freezing tolerance of cold-acclimated winter rye and which is believed to be the formation of domains of interdigitated lipids in the L{sub {beta}} phase. This past year our efforts have included (a) characterization of the ultrastructural changes in the plasma membrane that are associated with freezing injury of protoplasts isolated from cold-acclimated rye leaves; (b) determinations of the hydration characteristics of plasma membrane lipids and model lipid mixtures, including the thermal dependence of the hydration characteristics; (c) studies of dehydration-induced phase transitions and demixing in model systems of plasma membrane lipids; (d) differential scanning calorimetry studies to determine the amount of freezable/unfreezable water that is associated with lipids; and (e) preliminary cryo-SEM observations of in situ ice formation in rye leaves. 11 refs.

• Research Organization: Cornell Univ., Ithaca, NY (USA). Dept. of Soil, Crop and Atmospheric Sciences
• Sponsoring Organization: USDOE; USDOE, Washington, DC (USA)
• DOE Contract Number: FG02-84ER13214
• OSTI ID: 5840280
• Report Number(s): DOE/ER/13214-5; ON: DE91012640
• Country of Publication: United States
• Language: English

Related Subjects

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
59 BASIC BIOLOGICAL SCIENCES
CELL MEMBRANES
MOLECULAR STRUCTURE
PHASE TRANSFORMATIONS
FREEZING
BIOLOGICAL EFFECTS
LIPIDS
HYDRATION
PLANT CELLS
BIOLOGICAL ADAPTATION
BIOPHYSICS
CRYOBIOLOGY
DEHYDRATION
LIPOSOMES
LYSIS
PHOSPHOLIPIDS
PROGRESS REPORT
RYE
SCANNING ELECTRON MICROSCOPY
STEROLS
TEMPERATURE EFFECTS
BIOLOGY
CELL CONSTITUENTS
CEREALS
DOCUMENT TYPES
ELECTRON MICROSCOPY
ESTERS
GRAMINEAE
HYDROXY COMPOUNDS
LILIOPSIDA
MAGNOLIOPHYTA
MEMBRANES
MICROSCOPY
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
ORGANOIDS
PLANTS
SOLVATION
STEROIDS
560200* - Thermal Effects
550300 - Cytology