Injury prevention probability reduction

The first protein hypothesis explained freezing injury by a precipitation of proteins due to the freeze-induced increase in salt concentration. This concept is opposed by the absence of a reduction in the activity of most enzymes in freeze-killed plants. Many results point to membranes, and more specifically to their ATPases as the initial locus of freezing injury. Due to their role as ion pumps, their inactivation by freezing is the probable cause of the well-known efflux of ions from freeze-injured tissues. Freezing tolerance of plants is apparently associated with protein changes in both quality and quantity, and also with the accumulation of protective substances that prevent ATPase inactivation. 

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