title: Hormonal dynamics contributes to divergence in seasonal stomatal behaviour in a monsoonal plant community.
abstract: The plant hormone abscisic acid (ABA) is a primary regulator of plant transpiration, but its influence in determining seasonal stomatal behaviour in natural plant communities is poorly understood. We examined distantly related vascular plants growing together in a seasonally dry, monsoonal environment to determine whether ABA dynamics contributed to contrasting water use patterns in this natural setting. Regular sampling of angiosperm, cycad, conifer and fern species revealed characteristic seasonal patterns in ABA production, but these were highly distinct among species. Although no general relationship was observed between ABA levels, plant hydration or stomatal conductance among species, the seasonal dynamics in stomatal behaviour within species were predictable functions of either ABA or leaf water potential. Strong divergence in the seasonal role of ABA among species suggests that modification in ABA-stomatal interactions represents an important evolutionary pathway for adaptation in plant water use.
authors.affiliation: School of Biological Sciences, University of Tasmania, Private Bag 55, Hobart, Tasmania, 7001, Australia.
authors.forename: Scott A M
authors.initials: SA
authors.lastname: McAdam
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Brodribb
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism*; D000222:Adaptation, Physiological; D032462:Cycadopsida / Q000502:physiology; D055864:Droughts; D019669:Embryophyta / Q000502:physiology*; D029624:Ferns / Q000502:physiology; D019684:Magnoliopsida / Q000502:physiology; D010937:Plant Growth Regulators / Q000378:metabolism*; D018515:Plant Leaves / Q000502:physiology; D054046:Plant Stomata / Q000502:physiology*; D018526:Plant Transpiration / Q000502:physiology*; D012621:Seasons; D013045:Species Specificity; D014867:Water / Q000502:physiology
chemical_list: D010937:Plant Growth Regulators; D014867:Water; D000040:Abscisic Acid
keywords: abscisic acid (ABA); plant ecological diversity; stomata; water management