|Arora, Rajeev - WV UNIVERSITY|
Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: June 1, 1999
Publication Date: N/A
Technical Abstract: Woody plants in temperate climates are exposed to several types of freezing stress including low-temperature extremes, ice encasement, and unseasonal episodes of frost. In response to seasonal changes in growing conditions, plants have evolved the ability to both cold acclimate and undergo a period of dormancy. Strategies allowing plants to survive freezing temperatures fall into two categories, freezing tolerance and freezing avoidance. Mechanisms falling into both categories are common to woody plants. The objective of the present review is to discuss how plant structure and biochemistry contribute to defining cold hardiness in woody plants. The process of ice nucleation and the role of intrinsic vs. Extrinsic ice nucleating agents are discussed. The discovery of antifreeze proteins in peach tissues and their putative role in cold hardiness is also presented. The structural basis for deep supercooling of flower buds and xylem tissues sand its importance to cold acclimation in temperate woody plants such as fruit trees is reviewed in detail. The isolation of specific genes induced by low temperatures and their putative role in stress tolerance is discussed. Particular attention is placed on the dehydrin family of proteins and the isolation of a dehydrin gene from cold-acclimated bark tissues of peach. The functional role of bark storage proteins is presented and recent research on the role of phytochrome in cold acclimation and dormancy is presented. A review of glass formation in extremely hardy woody plants is briefly presented. In conclusion, future avenues of research are highlighted.