METHOD: Ion Leakage CONDITIONS: Biotron - 14h light at 18-20C or 2-4C with 70% RH METHOD NARR: Freezing tolerance was determined by measuring ion leakage following several freezing temperatures. The experiment also included extron of total and heat-stable proteins, lactate dehydrogenase cryoprotective assay and detection of dehydrin by Western blotting. RESULTS NARR: The concentration of heat-stable proteins increased following cold acclimation.elationship was found between heat-stable protein concentrations and nonacclimated (NARFT), acclimated (ACRFT) relative freezing tolerance and acclimation capacity (ACC). Except for S. sanctae rosea, dehydrin increased markedly. There appeared to be no systematic relationship of dehydrin expression with NARFT, ACRFT and ACC. AUTHOR EXPLANATION: The LDH cryoprotection study indicates that other heat-stable proteins (HSP) or components may be important facerance. HSP increase in tbr and cph may be a general stress response. It does not appear that dehydrin alone can explain the range of freezing tolerances in these materials. Cmm had the highest ACC and demonstrated thebehavior of the HSP. The quantitative increase in HSP during cold acclimation may not be responsible for the quantitative changes in freezing tolerance following cold acclimation.