title: Role of Endogenous Abscisic Acid in Potato Microtuber Dormancy.
abstract: 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.
authors.affiliation: United States Department of Agriculture, Northern Crop Science Laboratory, P.O. Box 5677, State University Station, Fargo, North Dakota 58105-5677.
authors.forename: J. C.
authors.initials: JC
authors.lastname: Suttle
authors.forename: J. F.
authors.initials: JF
authors.lastname: Hultstrand