Cold hardening
1274206
135242680
2007-06-02T03:20:03Z
Warfreak
369645
Reverted 1 edit by [[Special:Contributions/220.237.102.144|220.237.102.144]] to last revision by [[User:71.72.64.148|71.72.64.148]]. using [[WP:TWINKLE|TW]]
'''Cold hardening''' is the [[physiological]] and [[biochemical]] process by which an [[organism]] prepares for cold [[weather]].
==Plants==
[[Image:Plant cell structure svg.svg|thumb|200px|Schematic of typical plant cell]]
During the [[winter]] months, as the leaves fall off [[deciduous]] species and the [[temperature]] drops, the cold forces a stop to [[water]] movement in [[plant]]s. Freezing water can also cause irreversible damage to [[Cell (biology)|cell]]s in plants water solidifies. To guard against this, plants prepare for winter with a process called cold hardening. The process begins as the [[cell membrane]] permeability undergoes a change that permits water to seep into the intracellular voids. In addition, the cells store large amounts of sugars in the [[protoplasm]], decreasing its freezing point.
Cold hardening protects plants from both chilling injury and freezing injury. Chilling injury occurs at 0-10 degrees Celsius, as a result of membrane damage, metabolic changes, and toxic buildup. Symptoms include wilting, water soaking, [[necrosis|necrosis]], [[chlorosis|chlorosis]], ion leakage, and decreased growth. Freezing injury occurs at temperatures below 0 degrees Celsius. Symptoms of extracellular freezing include structural damage, dehydration, and necrosis. If intracellular freezing occurs, it will lead to death. Freezing injury is a result of lost permeability, plasmolysis, and post-thaw cell bursting.
{{ecology-stub}}
[[Category:Physiology]]