The ability, possessed by many temperate and arctic plants, to withstand subzero temperatures. The resistance is technically frost tolerance as the plant cannot avoid the cold conditions and resultant freezing of water in the intercellular spaces. This causes a lowering of the water potential in the intercellular spaces so water moves out of the protoplast to regions of ice crystallization. Frost damage is thus often a result of severe cellular dehydration. However this dehydration increases the solute concentration of the cell and thus makes ice formation within the cell less likely. Dormant organs and seeds tend to show more frost resistance than actively growing tissue. The mechanism of frost resistance is uncertain but membrane elasticity and reduction in cell size appear to play a part. See also hardening. |
