ABSTRACT
Being biochemical processes, all metabolic reactions running in a plant cell depend on environment temperature. Yet it is not possible to predict metabolic homeostasis solely based on thermodynamic considerations, because environmental changes also act as stimuli that trigger regulatory processes having strong impact on cellular function. Exposure of plants to low but non-freezing temperatures induces a multitude of changes at the levels of gene expression, protein abundance and metabolite levels. In numerous plant species, the cold-induced reprogramming of metabolism is part of a highly complex and multifaceted process termed cold acclimation, which ultimately leads to an increase of the organism’s freezing tolerance. The analysis of freezing tolerance of over 70 accessions of the annual weed Arabidopsis thaliana indicated a highly signifi cant positive correlation between freezing tolerance and latitude of the accessions’ origin (Zhen and Ungerer 2008; Hannah et al. 2006). Numerous studies have improved our understanding of the physiological mechanisms leading to increased freezing tolerance, and it was demonstrated convincingly that transcriptional regulation, changes in enzyme activities as well as modifi cations of membrane composition and metabolite concentrations are essential in cold acclimation (Hannah et al. 2006; Stitt and Hurry 2002; Cook et al. 2004; Davey et al. 2009).
