ABA and Cycloheximide Treatments. Only stem-cultured Sc
plants were used. Different concentrations of ABA (mg/l) were
added to culture medium. Immediately, plants were transferred
on to the medium for acclimation (5), solidified with 0.3% agar.
Plants transferred to the medium without added ABA served as
controls. Control and treated plants were divided into two groups
and grown in regimes of 25°C or 2°C temperature, both with 14-
h photoperiod.
Cycloheximide (l0-5 M) was added to the medium with or
without added ABA (20 mg/l). Plants on media with added ABA
were exposed to 25°C temperature and without added ABA to
2°C temperature.
Frost hardiness of leaves of control, ABA- and cycloheximidetreated
plants was determined after 15 d of treatment.
An additional treatment of cycloheximide (10-' M) was made to
plants after 5 d of 2°C temperature conditioning. Frost hardiness
of leaves of the treated plants was determined after an additional
11 d of 2°C temperature conditioning.