EFFECT OF RETARDANTS ON THE EARLY STAGES OF CUCUMBER ACCLIMATION TO CHILLING TEMPERATURES

The effects of dextrel (0.1, 1.0, and 10.0 mg/l) and chlorocholine chl oride (CCC, 1.0 and 10.0 mg/l) on the early stages of the development of cold resistance in cucumber (Cucumis sativus L.) seedlings were stu died at hardening (10 and 8 degrees C) and injurious (4 degrees C) tem peratures. Other environmental conditions were constant. The effect of the retardants was shown to depend on pretreatment duration and retar dant concentration. Dextrel at concentrations of 0.1 and 1.0 mg/l enha nced the initial processes of adaptation on the first day after seedli ng exposure to 10 degrees C. This effect was observed when the retarda nt was applied to leaves or roots just before hardening. Similarity to the effect of heteroauxin under similar conditions was demonstrated. At low injurious temperature (one day at 4 degrees C), when the adapti ve capacity of cucumber seedlings decreased, dextrel counteracted the loss of seedling adaptive potential more effectively than CCC.