Loss of Freezing Tolerance Associated with Decrease in Sugar Concentrations by Short-term Deacclimation in Cabbage Seedlings

Abstract

Cabbage seedlings cold-acclimated for 8 days at 5°C were transferred to 15, 20 or 25°C in the dark or light. The acquired freezing tolerance was reversed during deacclimation at all temperatures ; the higher the deacclimation temperature, the more accelerated was the loss of freezing tolerance. Concentrations of soluble sugars, particularly sucrose in the leaves, rapidly decreased within deacclimation for 1 to 3 hr at 20°C in the dark. This reduction was accompanied with a decrease in the freezing tolerance of leaves. Activities of soluble acid invertase in leaves were not affected by short-term deacclimation.