Frost hardiness depending on carbohydrate changes during cold acclimation in wheat

The effect of cold hardening on the dynamics of frost tolerance and on carb ohydrate metabolism was studied in the frost-sensitive Chinese Spring and t he frost tolerant Cheyenne genotypes, and in some of the chromosome substit ution lines, derived from the crosses of the donor Cheyenne to Chinese Spri ng. Total water-soluble carbohydrate, glucose, fructose, sucrose and fructa n contents were measured in the leaves. Differences in the accumulation of carbohydrates associated with cold tolerance occurred early in response to low temperature. Total water-soluble carbohydrates and total fructan conten t increased continuously during the cold treatment in all genotypes, result ing in higher contents in tolerant genotypes than in sensitive ones. Their rate of accumulation correlated significantly with the frost tolerance afte r 19 days of cold treatment. During the cold acclimation, the maximum of fr uctose accumulation proceeded that of sucrose. Significant correlation was detected between fructose and sucrose content and frost hardiness on the 43 rd day of cold treatment. Fructose accumulated to a greater extent in the m ost tolerant genotypes with a sharp peak on the 35th day of cold hardening, followed by a decrease. In the chromosome substitution lines, the consider able sucrose accumulation started after the 11th day with a maximum on the 43rd day of cold hardening, coinciding with the tolerance test. (C) 1999 El sevier Science Ireland Ltd. All rights reserved.