title: Characterization and Role of an Endogenous Inhibitor in the Induction of Cold Hardiness in Acer negundo.
abstract: An inhibitor extracted from short day treated Acer negundo leaves was compared to abscisic acid in 4 different solvent systems. The chromatographic properties of abscisic acid and the inhibitor were in very close agreement. Treatment of Acer negundo plants under non-hardening preconditions (long days) with either the inhibitor or abscisic acid increased hardiness after a hardening period of 3 weeks at 40 degrees . A gibberellin-inhibitor relationship was further studied by making comparison of extracts of plants subjected to either 4 weeks of long days, long days + 5 degrees nights, or short days. These tests indicated that gibberellin-like activity was greatest when the treatment included long days. Abscisic acid-like levels were highest when the treatments consisted of short days or long days + 5 degrees nights. Since the latter groups are the most capable of developing hardiness, the hardening process appears to be more closely related to a build-up of abscisic acid levels than a reduction of gibberellin levels.
authors.affiliation: Department of Horticulture, Oklahoma State University, Stillwater, Oklahoma 60076.
authors.forename: R M
authors.initials: RM
authors.lastname: Irving