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.

Item Type:	Refereed Article
Keywords:	abscisic acid (ABA), plant ecological diversity, stomata, water management
Research Division:	Biological Sciences
Research Group:	Plant biology
Research Field:	Plant physiology
Objective Division:	Expanding Knowledge
Objective Group:	Expanding knowledge
Objective Field:	Expanding knowledge in the biological sciences
UTAS Author:	McAdam, SAM (Dr Scott McAdam)
UTAS Author:	Brodribb, TJ (Professor Tim Brodribb)
ID Code:	98319
Year Published:	2015 (online first 2014)
Funding Support:	Australian Research Council (DE140100946)
Web of Science® Times Cited:	14
Deposited By:	Plant Science
Deposited On:	2015-02-11
Last Modified:	2017-11-01
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