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The environmental control of cold acclimation in apple
1Department of Horticultural Science, University of Minnesota, St. Paul, Minnesota 55101.
Plant Physiology
|April 1, 1970
Summary
Short days and frost induce cold acclimation in apple bark. Leaves produce substances promoting acclimation under short days, while long days inhibit it, with frost essential for maximum hardiness.
Area of Science:
- Plant Physiology
- Environmental Stress Biology
- Horticultural Science
Background:
- Cold acclimation is crucial for perennial plant survival in temperate climates.
- Photoperiod and temperature are key environmental cues influencing plant dormancy and hardiness.
Purpose of the Study:
- To investigate the roles of photoperiod and temperature in the cold acclimation of Haralson apple (Pyrus malus L.) bark.
- To elucidate the mechanisms and stages involved in autumn cold hardening.
Main Methods:
- Field study in Minnesota during autumn.
- Manipulation of photoperiod (natural, lengthened days) and temperature (warmed nights).
- Manual leaf removal and exposure to natural frost conditions.
Main Results:
- Cold acclimation occurs in two distinct stages: one induced by short days and another by frost/low temperature.
- Short days stimulate leaves to produce translocatable substances that promote bark cold acclimation.
- Long days produce inhibitory substances, while frost is necessary for maximum hardiness (-55°C).
Conclusions:
- Short days and frost regulate independent endogenous acclimation processes in apple bark.
- Translocatable factors from leaves are involved in the first stage of acclimation, but not the second.
- Environmental cues like photoperiod and frost are critical for developing winter hardiness in fruit trees.
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