ZINC TOLERANCE, UPTAKE, AND ACCUMULATION IN THE WETLAND PLANTS ERIOPHORUM ANGUSTIFOLIUM, JUNCUS EFFUSUS, AND JUNCUS ARTICULATUS

摘要

Metal tolerance in plants is thought to evolve following exposure to elevated metal levels in the soil. However, there are examples of species that appear to have developed constitutive metal tolerance without apparent exposure to metals. In previous studies, populations from contaminated and non-contaminated sites of the wetland plants Typha latifolia, Phragmites australis, and Glyceria fluitans were found to be equally tolerant to high concentrations of metals. In this study, zinc uptake and growth responses of populations of Eriophorum angustifolium, Juncus effusus, and Juncus articulatus from zinc-contaminated and non-contaminated sites were compared as part of a research project investigating metal tolerance in wetland plants. The populations were grown hydroponically in zinc-amended nutrient solutions. Juncus articulatus could not grow in the presence of elevated zinc concentrations, and no growth differences between populations were observed. Both populations of Juncus effusus from contaminated and non-contaminated sites grew well in moderately elevated zinc concentrations, but growth was inhibited at the higher treatment levels. Growth of Eriophorum angustifolium was inhibited less than growth of Juncus effusus at the higher zinc treatment levels. Both populations were able to tolerate concentrations of zinc of up to 1000 μmol L~(-1). The findings for Juncus effusus and Eriophorum angustifolium support the theory that wetland plants tend to be tolerant to exposure to high levels of metals, but the results for Juncus articulatus suggest that this is not a general rule.