Evaluation of heavy metal tolerance in Calamagrostis epigejos and Elymus repens revealed copper tolerance in a copper smelter population of C-epigejos

Populations of the two rhizomatous perennial grasses Calamagrostis epigejos and Elymus repens from the vicinity of copper smelters in Poland, sewage farmland in Berlin and unpolluted control sites were examined for tolerance to copper, zinc, lead, and cadmium. Metal tolerance tests were performed using the "in parallel" root elongation method with 2 mumol l(-1) Cu, 10 and 20 mumol l(-1) Zn, 5 and 10 mumol l(-1) Pb, and 5 and 10 mumol l(-1) Cd test solutions. Additionally, a transplant experiment with two uncontaminated substrates and two contaminated soils was performed. The tolerance tests revealed different responses to the four metals between the two species as well as between populations within species. In general, C. epigejos was less sensitive to Cu, Pb, and Cd, but more sensitive to Zn than E. repens. The tolerance indices of the copper smelter population of C. epigejos were significantly higher than those of other populations indicating evolved copper tolerance in C. epigejos. All tested populations also revealed a constitutional Pb tolerance, which was more pronounced in C epigejos than in E. repens. Constitutional tolerance can also be assumed with respect to Cd in C. epigejos and to Zn in E. repens. The different responses to metal toxicity were confirmed in the transplant experiment. The population of C. epigejos from the uncontaminated site performed best on substrates of low and medium contamination level, whereas the copper smelter population was the best of three populations on the highly contaminated substrate. On copper smelter soil, biomass production of E. repens was much more reduced than that of C. epigejos. (C) 2003 Elsevier B.V. All rights reserved.