title: The influence of plant density on the responses of Sinapis alba to CO2and windspeed.
abstract: Plants in nature live in populations of variable density, a characteristic which may influence individual plant responses to the environment. We investigated how the responses of Sinapis alba plants to different wind speeds and CO2concentrations could be modified by plant density. In our wind-density experiment the expectation that mechanical and physiological effects of wind will be ameliorated by growing in high density, as a result of positive plant interactions, was realised. Although individual plants were smaller at higher densities, the effect of increasing windspeed was much less than at lower plant densities. A similar reduced sensitivity of individual plant growth under high densities was also observed under CO2enrichment. When measured as a population or stand response, there was no effect of density on the CO2responses, with all stands showing very similar increases in total biomass with CO2enrichment. In the wind speed experiment, total biomass per stand increased significantly with density, although there was no effect of density on the wind speed response. Specific leaf area decreased with increasing wind speed and this response was significantly affected by the density at which the plants grew.
authors.affiliation: Area de Ecología, Facultad de Biología, Universidad de Santiago, 15706, Santiago, Spain. bfretuer@usc.es.
authors.forename: R
authors.initials: R
authors.lastname: Retuerto
authors.affiliation: Département de Phytologie, Faculté des Sciences de l'Agriculture et de l'Alimentation, G1 K 7P4, Quebec, Canada.
authors.forename: L
authors.initials: L
authors.lastname: Rochefort
authors.affiliation: Department of Animal and Plant Sciences, The University of Sheffield, PO Box 601, S10 2UQ, UK.
authors.forename: F I
authors.initials: FI
authors.lastname: Woodward
keywords: Biomass allocation; CO2 concentrations; Density; Growth analysis; Windspeed