Phenotypic plasticity in response to mechanical stress: hydrodynamic performance and fitness of four aquatic plant species.
Plastic responses of plants exposed to mechanical stress can lead to modified, performance-enhancing, morphologies, sometimes accompanied by costs to reproduction. The capacity to present short-term plastic responses to current stress, the resulting performance (expected lower mechanical forces), and the costs of such responses to reproduction were tested for four aquatic plant species. Two ramets of the same genet were submitted to running vs standing water treatment. Traits describing the morphology, hydrodynamic performance and reproduction (sexual and vegetative) were measured. For one species, plastic responses led to reduced hydrodynamic forces, without apparent costs to reproduction, indicating that the plastic response could be beneficial for plant maintenance in stressful habitats. For two species, plastic responses were not associated with variations in performance and reproduction, possibly because of the low hydrodynamic forces experienced, even for morphologies produced under standing conditions. For one species, plastic responses were associated with a sharp decrease in sexual reproduction, without variations in performance, revealing the negative impact of currents over a short time scale. Species maintenance is linked to the capacity of individuals to tolerate mechanical forces. The contrasting responses to currents may be a key element for predicting community dynamics.
Puijalon
Sara
S
UMR CNRS 5023, 'Ecology of Fluvial Hydrosystems', Université Lyon 1, 43 Boulevard du 11 novembre 1918, F-69622 Villeurbanne Cedex, France.|Present address: Netherlands Institute of Ecology (NIOO-KNAW), Centre for Estuarine and Marine Ecology, PO Box 140, 4400 AC Yerseke, the Netherlands.
Léna
Jean-Paul
JP
UMR CNRS 5023, 'Ecology of Fluvial Hydrosystems', Université Lyon 1, 43 Boulevard du 11 novembre 1918, F-69622 Villeurbanne Cedex, France.
Rivière
Nicolas
N
Laboratoire de Mécanique des Fluides et d'Acoustique, Institut National des Sciences Appliquées de Lyon, F-69621 Villeurbanne Cedex, France.
Champagne
Jean-Yves
JY
Laboratoire de Mécanique des Fluides et d'Acoustique, Institut National des Sciences Appliquées de Lyon, F-69621 Villeurbanne Cedex, France.
Rostan
Jean-Claude
JC
UMR CNRS 5023, 'Ecology of Fluvial Hydrosystems', Université Lyon 1, 43 Boulevard du 11 novembre 1918, F-69622 Villeurbanne Cedex, France.
Bornette
Gudrun
G
UMR CNRS 5023, 'Ecology of Fluvial Hydrosystems', Université Lyon 1, 43 Boulevard du 11 novembre 1918, F-69622 Villeurbanne Cedex, France.
D001696:Biomechanical Phenomena; D017753:Ecosystem; D035264:Flowers / Q000502:physiology; D010944:Plants / Q000033:anatomy & histology* / Q000378:metabolism*; D012098:Reproduction / Q000502:physiology; D014867:Water / Q000502:physiology*
D014867:Water