Abstract
Freezing tolerance is an important character for plants living under subzero temperatures in winter season. The growth of ice crystals or the freeze-induced dehydration mechanically may disrupt the plasma membrane. In animal cells, the mechanically disrupted plasma membrane is rapidly repaired dependently on the extracellular calcium, although no report has been published on this mechanism in plant cells. It is expected that the cryostability of plasma membrane is tightly associated with the membrane repair manner. To study the relationship between the membrane repair and the enhanced freezing tolerance, the calcium-dependent survival for freezing stress was measured using Arabidopsis thaliana protoplasts or living leaf sections, which were isolated from control and cold-acclimated leaves. Finally, the results indicated that the tolerance to mechanical stress caused by the ice crystal growing was dependent on the extracellular calcium, which might be related with membrane repair manner.
