A qualitative model for the mechanism of sugar accumulation in cold-stressed plant tissues

Abstract

Summ. Low temperatures induce the accumulation of soluble sugars in plant cells. An attempt is made to identify the primary site of action of low temperatures and the sequence of physiological and biochemical events leading to sugar accumulation. The integration of all the available information points to a central role of increased intracellular calcium ion concentration generated by the inhibition of ATPases concerned with its homeostasis. A positive role of a cold-induced dysfunction of mitochondrial and chloroplast electron flow is also proposed. The biological significance of an explanation of this physiological response to a stress factor relies on its categorization into the major family of those employing alternative energy-producing pathways under stress conditions. More specifically, a connection of sugar mobilization to the needs of the cold-stressed cell to employ fermentative energy-producing mechanisms is made. From this ankle of view, new ways of genetically modifying the ability of plant cells to accumulate sugars become obvious.