PLANT PHYSIOLOGY , Vol 105, Issue 3 891-896, Copyright © 1994 by American Society of Plant Biologists
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DEVELOPMENT AND GROWTH REGULATION |
Role of Endogenous Abscisic Acid in Potato Microtuber Dormancy
J. C. Suttle and J. F. Hultstrand
United States Department of Agriculture, Northern Crop Science Laboratory, P.O. Box 5677, State University Station, Fargo, North Dakota 58105-5677
Potato (Solanum tuberosum L. cv Russet Burbank) microtubers generated in
vitro from single-node explants contained substantial amounts
(approximately 250 pmol/g fresh weight) of free abscisic acid (ABA) and
were completely dormant for a minimum of 12 weeks. Microtubers that
developed in the presence of 10 [mu]M fluridone (FLD) contained
considerably reduced amounts (approximately 5-25 pmol/g fresh weight) of
free ABA and exhibited a precocious loss of dormancy. Inclusion of
exogenous racemic ABA in the FLD-containing medium suppressed the premature
sprouting of these microtubers in a dose-dependent manner. At a
concentration of 50 [mu]M, exogenous ABA restored internal ABA levels to
control values and completely inhibited FLD-induced precocious sprouting.
Exogenous jasmonic acid was ineffective in suppressing FLD-induced
sprouting. Application of FLD to preformed, fully dormant microtubers also
resulted in a reduction in internal ABA content and precocious sprouting.
These results indicate that endogenous ABA is essential for the induction
and maintenance of potato microtuber dormancy.