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Extreme Low Temperature Tolerance in Trees
Have you ever walked by a tree on a bitter cold day and felt the urge to tie a scarf around that poor exposed bark?
Research indicates that trees have something much more effective going for them in winter than our sympathy.
Working with scientists in Norway and Sweden, Paul Schaberg, a research plant physiologist with the Northern Research Station’s lab in Burlington, Vermont, explored exactly how woody plants succeed in surviving extreme low temperatures. While extreme low temperature tolerance can be generally defined as the ability to survive freezing, at least under laboratory conditions, to temperatures below -76 degrees Fahrenheit, Schaberg’s and other research has shown that tissues of tree species from boreal and arctic environments can survive at temperatures approaching absolute zero ( minus 460 degrees Fahrenheit), indicating “absolute” low temperature tolerance.
The secret to greater low temperature tolerance is related to changes in three basic cellular components: 1) the composition of membranes, 2) increases in certain sugars, and 3) increases in special dehydrin proteins – so named because they help protect against freeze-induced dehydration. Together, changes in these components can result in near total protection from the cold when needed. Importantly, these changes are also reversible – allowing for more efficient plant function and growth when milder temperatures prevail.
Results of this work may give us insight into how to better preserve food and medication as well as contribute to understanding and predicting the implications of global warming for individual tree species and forest ecosystems, especially in boreal regions.
The study was published in the journal Frontiers in Plant Science and is available online at: http://www.nrs.fs.fed.us/pubs/49739