Biochemical and Biophysical Changes in Relation to Cold Hardiness

Abstract

Winter temperatures below −40°C are not uncommon in northern regions. Low temperatures, often combined with strong winds, pose a significant survival challenge to perennial woody plants. Unlike deciduous species, most northern conifers retain their needles over winter. This allows the trees to photosynthesise during warm days in early spring and late fall and therefore take advantage of good conditions (Fischer and Höll 1991; Wang and Zwiazek 1999a). However, this strategy requires freezing resistance mechanisms to protect the needles in addition to the other living tissues.