Development, photosynthetic activity and habitat selection of the clonal plant Fragaria vesca growing in copper-polluted soil.

The ability of clonal systems to spread by ramet production may expose the clone to spatial heterogeneity. This study explored the physiological and morphological responses in the clonal plant Fragaria vesca L. growing in homogeneous (Cu-contaminated or uncontaminated) or in heterogeneous environments with patches of contrasting quality (Cu-contaminated or uncontaminated). We also investigated the potential of this species to selectively establish ramets within a heterogeneous environment. In heterogeneous environments, plants expanded ramets randomly, but selectively established ramets in the favourable patches. We discuss whether the selective establishment of ramets is a consequence of direct suppression of plant growth due to copper toxicity. The assimilate demand from offspring ramets in unfavourable environments increased the chlorophyll content and photosynthetic efficiency of parents by a feedback regulation process. Integration ameliorated the effects of copper on the photochemical efficiency of the offspring ramets. We did not observe integration costs, in terms of total biomass, for parents supporting ramets in Cu-contaminated environments, although we did detect costs in terms of ramet production. Parents with offspring ramets in Cu-contaminated environments produced 25 times more reproductive biomass than parents with offspring ramets in uncontaminated environments. We interpret this as a strategy for escaping from stressful environments. In this study, we extend the concept of physiological integration in clonal plants to include photochemical responses.