METAL TOLERANCE IN AGROSTIS-SCABRA FROM THE SUDBURY, ONTARIO, AREA

Acid, metal-contaminated soils are frequently colonized by plant speci es that have evolved tolerance to metals. Agrostis scabra (tickle gras s) grows at several such sites in the Sudbury area. To test whether th ese populations were tolerant to metals, three experiments were perfor med. A hydroponic root growth experiment, in which clonal ramets from contaminated and uncontaminated sites were grown in metal-amended nutr ient solutions, showed that plants from the Sudbury area had greater t olerance indices than those from outside Sudbury. A seed-based hydropo nic experiment, where seeds were germinated in metal solutions, showed that metal-tolerance indices calculated from root growth were mostly greater for populations from Sudbury but that leaf growth was not a go od indicator of metal tolerance. A seed-based soil-bioassay experiment , in which seeds were germinated on soils covered with filter paper, s howed that seeds from contaminated sites performed better on contamina ted soil and a 50:50 soil mixture (contaminated-uncontaminated) than t hose from uncontaminated sites. Populations of A. scabra growing on co ntaminated soils in the Sudbury area therefore appear to have been sel ected for metal tolerance. Ecological aspects of metal tolerance and t he possible role of A. scabra in the revegetation of the Sudbury area are discussed.