Cold comfort farm: the acclimation of plants to freezing temperatures

Plant acclimation to freezing temperatures is very complex. Many temperate plants increase in freezing tolerance upon exposure to a period of low but non-freezing temperatures, an adaptive process known as cold acclimation, T his acclimation phenomenon has encouraged investigations of physiological, biochemical, and molecular changes that are associated,vith the development of freezing tolerance, Although many biochemical add gene-expression chang es occur during cold acclimation, few have been unequivocally demonstrated to contribute to the development of freezing tolerance. However, in the las t few years, exciting new progress has been made through the use of mutatio nal analysis and molecular genetic approaches, We now recognize that severa l interacting signal pathways are activated to bring about cold acclimation and ensure the winter survival of plants. The challenge for the future is to understand these pathways at a mechanistic level,Facile map-based clonin g in Arabidopsis and techniques (such as DNA micro-arrays) for transcript p rofiling will provide the tools needed for this task.