Sap flow from excised maple stems collected over the winter (1986/87) was correlated with stem water content. Stem water content was high in the fall (>0.80) and decreased rapidly during 2 weeks of continuous freezing temperatures in late winter (<0.60). Exudation of sap from stem segments subjected to freeze/thaw cycles was small (<10 mL/kg) in the fall, but substantial exudation (45-50 mL/kg)...

The meristematic tissues of temperate woody perennials must acclimate to freezing temperatures to survive the winter and resume growth the following year. To determine whether the C-repeat binding factor (CBF) family of transcription factors contributing to this process in annual herbaceous species also functions in woody perennials, we investigated the changes in phenotype and transcript profi...

This review compares fall acclimation patterns and lift/store practices for Pseudotsuga menziesii var. menziesii, Picea glauca (Moench) Voss x P. engelmannii Parry ex engelm and Pinus taeda L. seedlings. Spruce seedlings achieve budset and an endodormant state in late summer, coastal Douglas-fir in early fall, while loblolly pine achieves a less endodormant state with a limited amount of mitoti...

A great number of organismiis can wvithstan(d temperatures below the freezing point of water. Many plants are even resistant against severe frosts especially during the winter months. In the late spring, during summer and in the early fall, however, they may be killed by moderate frosts. In order to gain resistance they must undergo a hardening process; in spring this resistance is lost by deha...

Rainbow smelt (Osmerus mordax) inhabit inshore waters along the North American Atlantic coast. During the winter, these waters are frequently ice covered and can reach temperatures as low as -1.9 degrees C. To prevent freezing, smelt accumulate high levels of glycerol, which lower the freezing point via colligative means, and antifreeze proteins (AFP). The up-regulation of the antifreeze respon...

Miscanthus × giganteus grown in cool temperate regions of North America and Europe can exhibit severe mortality in the year after planting, and poor frost tolerance of leaves. Spartina pectinata (prairie cordgrass), a productive C4 perennial grass native to North America, has been suggested as an alternative biofuel feedstock for colder regions; however, its cold tolerance relative to M. × giga...

Reactive oxygen species (ROS) are harmful to living organisms due to the potential oxidation of membranes, DNA, proteins, and carbohydrates. Freezing injury has been shown to involve the attack of ROS. Antioxidant enzymes can protect plant cells from oxidative stress imposed by freezing injury, therefore, cold acclimation may involve an increase in the expression of antioxidant enzymes. In this...

Polar stratospheric clouds (PSC) have been observed in early winter (December 2002) during the SOLVE II/Vintersol campaign, both from balloons carrying comprehensive instrumentation for measurements of chemical composition, size distributions, and optical properties of the particles, as well as from individual backscatter soundings from Esrange and Sodankylä. The observations are unique in the ...

Winter cultivars of rye (Secale cereale L., cv Musketeer) and wheat (Triticum aestivum L. cvs Kharkov and Monopol), but not a spring cultivar of wheat (Glenlea), grown at cold-hardening temperatures showed, at high irradiances, a higher proportion of oxidized to reduced primary, stable quinone receptor (QA) than did the same cultivars grown under nonhardening conditions. In addition, there was ...

The crown is the below ground portion of the stem of a grass which contains meristematic cells that give rise to new shoots and roots following winter. To better understand mechanisms of survival from freezing, a histological analysis was performed on rye, wheat, barley and oat plants that had been frozen, thawed and allowed to resume growth under controlled conditions. Extensive tissue disrupt...