Physiological responses to low temperature

Abstract

Low temperature resistance in temperate zone woody plants is characterized by a market annual variation generally showing an inverse relationship between the growth activity and the level of hardiness. These annual changes in hardiness are controlled by an interaction between the genotype and environmental factors, especially day length and temperature. Cessation of elongation growth is a prere- quisite for acclimation in most species with a free growth pattern and this process is primarily controlled by photoperiod. Short- day-induced blockage of the biosynthesis of active gibberellin could be an early step leading to the cessation of growth. Cold acclimation is induced most effectively by a combination of short photoperiod and low temperature. Deacdimation is mainly a response to an increasing temperature. Cold hardiness is a quantitative character and its genetic background in woody plants.