Dynamics of low-temperature acclimation in temperate and boreal conifer foliage in a mild winter climate
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To provide baseline data for physiological studies of extreme low-temperature (LT) tolerance in boreal conifers, we profiled LT stress responses, liquid nitrogen (LN2)-quench tolerance, and sugar concentrations in foliage of boreal-temperate species pairs in the genera Abies, Picea and Pinus, growing in an arboretum in a temperate oceanic climate from August 2006 through April 2007. The boreal species acclimated more rapidly and deeply than the temperate species, acquiring LN2-quench tolerance by late November, despite unusually warm conditions throughout the autumn and early winter. Maximum LT tolerance in the temperate species was in the -25 to -35 °C range, and was reached only after a period of freezing temperatures in late January and February. During LT acclimation in the temperate species, sigmoid temperature-relative electrolyte leakage (REL) curves shifted toward lower temperatures, whereas in boreal species there was both a temperature shift and a lowering of the maximum REL until it fell below a threshold associated with irreversible injury. These differences may reflect differences in mechanisms of LT acclimation and LT tolerance.
KeywordsAbies; cold; frost; LN2-quench hardiness tolerance; Picea; Pinus; raffinose; stachyose; sucrose; sugar
Strimbeck, G. Richard; Kjellsen, Trygve D.; Schaberg, Paul G.; Murakami, Paula F. 2008. Dynamics of low-temperature acclimation in temperate and boreal conifer foliage in a mild winter climate. Tree Physiology. 28(9): 1365-1374. https://doi.org/10.1093/treephys/28.9.1365