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Cold Acclimation of Hedera helix: Evidence for a Two Phase Process
1Department of Floriculture and Ornamental Horticulture, Cornell University, Ithaca, New York 14850.
Plant Physiology
|February 1, 1971
Summary
Light and sugar accumulation are part of English ivy's cold acclimation, but a second protein-binding phase is crucial for increased hardiness. Both phases must complement each other for full cold tolerance.
Area of Science:
- Plant Physiology
- Molecular Biology
- Biochemistry
Background:
- Cold acclimation in plants is a complex process involving multiple physiological and molecular changes.
- Light influences early stages of cold acclimation, potentially through sugar production.
- Understanding the complete mechanism of cold hardiness is vital for plant survival in adverse conditions.
Purpose of the Study:
- To elucidate the distinct phases involved in cold acclimation in English ivy (Hedera helix L. var. Thorndale).
- To determine the role of light and sugar accumulation versus protein modification in cold hardiness.
- To investigate the independent and complementary functions of different cold acclimation pathways.
Main Methods:
- Differential exposure of plant parts to light and dark conditions.
- Application of 2,4-dinitrophenol to assess the role of light-generated promoters.
- Incubation in sucrose solutions to evaluate light-independent requirements.
- Analysis of sugar-binding capacity of proteins from acclimated and non-acclimated tissues.
Main Results:
- Light-enhanced sugar production alone does not confer increased cold hardiness.
- Cold acclimation involves at least two distinct phases: one light-dependent (sugar-related) and one dark-dependent (protein-related).
- Protein from cold-acclimated tissue shows a significantly higher sugar-binding capacity than that from non-acclimated tissue.
- Sucrose incubation can substitute for the light requirement, suggesting a role in the initial phase.
- Both phases can occur independently, but full cold hardiness requires the complementation of their products.
Conclusions:
- Cold acclimation in English ivy is a two-phase process requiring both light-mediated sugar accumulation and a subsequent dark-dependent protein modification phase.
- The increased sugar-binding capacity of proteins in cold-acclimated tissue is a key factor in developing enhanced cold hardiness.
- The findings highlight the intricate interplay between light signaling, carbohydrate metabolism, and protein alterations in plant cold tolerance.