Abscisic acid induced dormancy and hardening of in vitro Saskatoon berry (Amelanchier alnifolia Nutt.)
Date
1994-06
Authors
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ORCID
Type
Degree Level
Masters
Abstract
In vitro plantlets of Amelanchier alnifolia Nutt.
'Smoky' showed inhibited bud break in response to ABA
application to tissue culture growing medium, but did not
demonstrate a condition of innate dormancy. Partial
formation of terminal buds, and axillary bud transition in
phenotype from summer to winter form was produced by
inclusion of 50 µM ABA in tissue culture growing medium when
BA levels were decreased from 11.0µM to 5.5µM and NAA was
eliminated.
Addition of 50µM ABA to growing medium approximately
doubled the -5°C hardiness levels of control plantlets, but
ABA application alone did not generate hardiness levels as
high as those seen during low temperature/short day (4°C/8h)
acclimation (-27°C). Addition of BA to medium significantly
reduced the efficacy of ABA-induced freezing tolerance.
Wounding of plantlets during subculture was found to
produce a rapid but transitory increase in hardiness level
from -5°C to -9°C within 24 hours of subculture. Newlysubcultured
plantlets were found to increase in hardiness
more rapidly, and to a greater extent than reports
previously published for these plantlets in culture.
While short days (8h) slightly enhanced freezing
survival of plantlets under both warm (23°C) and cool (4°C)
temperatures, a pre-treatment of short warm days did not
increase the rate of plantlet hardening under cold inductive conditions.
Buds collected from orchard-grown plants demonstrated
rising innate dormancy levels in late summer, with maximum
levels between early September and late November. From
December to the time of natural spring bud break, innate
inhibition levels steadily decreased. Similar buds placed
in culture were induced to grow at all seasons on BAsupplemented
medium and were inhibited on ABA medium. On
hormone-free medium, growth responses of de-scaled buds
supported on stems above the medium were most similar to the
dormancy profile of buds generated outside of culture
conditions.
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Degree
Master of Science (M.Sc.)
Department
Horticulture
Program
Horticulture