EFFECT OF SEED FREEZING AND STORAGE-CONDITIONS ON PLASMA-MEMBRANE PROPERTIES OF NORWAY SPRUCE (PICEA-ABIES KARST.) SEEDLINGS

Norway spruce (Picea abies Karst.) seeds were frozen and stored for 15 months at + 3, - 25, - 75 or - 196 degrees C. After storage, seeds we re germinated for 9-14 days to determine viability and plasma membrane protein composition, H+-ATPase activity and fluidity. The results ind icate no significant differences in viability of seed 14 days after ge rmination. Biochemical analyses revealed increased plasma membrane flu idity in 9-day-old Norway spruce seedlings raised from seeds pretreate d at - 75 degrees C, and changes in the temperature profile of membran e fluidity in seedlings after pre-treatment of seeds at - 25 degrees C . On the other hand, the same treatments did not result in changes in plasma membrane protein content, protein composition or ATPase activit y. There was also no difference in plasma membrane H+-ATPase activity assayed in the presence of different ATP hydrolysis inhibitors. Based on the presented results, and other experimental data, we suggest that during early seedling growth, adaptation of seeds to - 25 and - 75 de grees C freezing and/or storage temperature results in stability of th e plasma membrane protein function and composition and increased fluid ity or changes in the temperature-dependent fluidity profile of these membranes.