A modular concept of plant foraging behaviour- the interplay between local responses and systemic.pdfVIP

A modular concept of plant foraging behaviour: the interplay between local responses and systemic control HANS DE KROON1, ERIC J. W. VISSER1, HEIDRUN HUBER1, LIESJE MOMMER1,2 MICHAEL J. HUTCHINGS3 1Department of Experimental Plant Ecology, Institute for Water and Wetland Research, Radboud University Nijmegen, P.O. Box 9010, 6500 GL Nijmegen, the Netherlands 2Nature Conservation and Plant Ecology, Wageningen University, Wageningen, the Netherlands and 3School of Life Sciences, University of Sussex, Falmer, Brighton, Sussex, UK ABSTRACT In this paper we examined the notion that plant foraging for resources in heterogeneous environments must involve: (1) plasticity at the level of individual modules in reaction to localized environmental signals; and (2) the potential for modification of these responses either by the signals received from connected modules that may be exposed to different conditions, or by the signals reflecting the overall resource status of the plant. A conceptual model is pre- sented to illustrate how plant foraging behaviour is achieved through these processes acting in concert, from the signal reception through signal transduction to morpho- logical or physiological response. Evidence to support the concept is reviewed, using selective root placement under nutritionally heterogeneous conditions and elongation responses of stems and petioles to shade as examples. We discussed how the adoption of this model can promote understanding of the ecological significance of foraging behaviour. We also identified a need to widen the experi- mental repertoires of both molecular physiology and ecology in order to increase our insight into both the regu- lation and functioning of foraging responses, and their rela- tionship with the patterns of environmental heterogeneity under which plants have evolved. Key-words: environmental heterogeneity; plasticity; module; resource acquisition; roots; shade-avoidance response; signal transduction pathway; signals. INTRO