title: Gibberellin Is Required for Flowering in Arabidopsis thaliana under Short Days.
abstract: Mutants of Arabidopsis thaliana deficient in gibberellin synthesis (ga1-3 and ga1-6), and a gibberellin-insensitive mutant (gai) were compared to the wild-type (WT) Landsberg erecta line for flowering time and leaf number when grown in either short days (SD) or continuous light (CL). The ga1-3 mutant, which is severely defective in ent-kaurene synthesis because it lacks most of the GA1 gene, never flowered in SD unless treated with exogenous gibberellin. After a prolonged period of vegetative growth, this mutant eventually underwent senescence without having produced flower buds. The gai mutant and the "leaky" ga1-6 mutant did flower in SD, but took somewhat longer than WT. All the mutants flowered readily in CL, although the ga1-3 mutant showed some delay. Unlike WT and ga1-3, the gai mutant failed to respond to gibberellin treatment by accelerating flowering in SD. A cold treatment promoted flowering in the WT and gai, but failed to induce flowering in ga1-3. From these results, it appears that gibberellin normally plays a role in initiating flowering of Arabidopsis.
authors.affiliation: Michigan State University-U.S. Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824.
authors.forename: R N
authors.initials: RN
authors.lastname: Wilson
authors.forename: J W
authors.initials: JW
authors.lastname: Heckman
authors.forename: C R
authors.initials: CR
authors.lastname: Somerville