Not every deviation from optimal life conditions is stress. These deviations are essential for fitness. Only those which are not fit are stressed. Alpine plants are fit for their particular environment. This is the reason why they thrive in environments where others cannot and where humans feel stressed. Low temperature extremes can cause partial tissue damage in summer but are never fatal for plants. While freezing resistance varies across a wide range of temperatures among species, heat resistance thresholds are relatively similar across species. Very sensitive species may be damaged at 46 °C, the maximum resistance in higher plants is around 56 °C, with most plant species being damaged at around 50 °C (±2 K). Extremely high solar radiation can be problematic during snowmelt, but alpine plants are generally well protected by UV filtering substances.

Part of this unit has been extracted from Körner Ch (2003) Alpine Plant Life: functional plant ecology of high mountain ecosystems. Springer, Berlin, chapter 8

Sakai A, Larcher W (1987) Frost survival of plants. Responses and adaptation to freezing stress. Ecol Stud, vol 62. Springer, Berlin

Christian Körner and Thomas Zumbrunn

29 August 2011
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