While the canonical plant hormones, auxin, cytokinin, abscisic acid, gibberellic acid, and ethylene, were originally isolated and described in vascular plants, each has also been shown to be able to regulate one or more aspects of growth and development in mosses. Since mosses are the sister clade to the vascular plants, this common set of hormones is hardly surprising. There are now some additional growth regulators discovered in vascular plants, jasmonates, salicylates, brassinolides, as well as oligosaccharins and even peptide homones, and it is not known if these molecules are also ancestral regulators or represent physiological innovations unique to the vascular plants. Using the classic bioassay system, bud-formation in the moss Funaria, our experiments find that exposure to salicylates produces dose-dependent inhibition of bud formation, with half-maximal inhibition at micromolar concentrations. Characterization of the time at which salicylates affect bud formation and the kinetics of the interaction with cytokinin concentration show the inhibition is not a direct antagonism of cytokinin. While these experiments do not show that mosses regularly use salicylates to regulate growth and development, they confirm the presence of a salicylate signal perception-transduction pathway in mosses and suggest its presence in the common ancestor of mosses and vascular plants. Research support, KU Undergraduate Biology Research Fund, NSF OSB-9550487.

Key words: bud-formation, development, Funaria hygrometrica, moss, salicylate