Storage Temperature and Duration Influence Cold Tolerance of Red Spruce Foliage

Abstract

Abstract Laboratory assessments of cold tolerance were conducted to examine the influence of duration and temperature of foliar sample storage on relative and absolute cold tolerance of excised shoots of red spruce (Picea rubens Sarg.) trees during midwinter and early spring. Although differences in cold tolerance associated with temperature and duration of sample storage were statistically significant, the rate of dehardening of red spruce foliar samples was largely a function of the storage temperature/duration combination rather than either temperature or duration alone. Foliar samples stored at 15°C dehardened significantly after 45 hours of storage, whereas samples stored at 24°C dehardened significantly after only 18 hours. Samples stored at 4°C for up to 72 hours were similar in cold tolerance to fresh samples. Foliar samples from different trees responded differentially to foliar sample storage regimes, indicating that both absolute and relative cold tolerance of individual trees may be altered by relatively short periods of sample storage at above-freezing temperatures. For. Sci. 36(4):1153-1158.