THE INFLUENCE OF COPPER AND ZINC ON SHOOT LENGTH AND DRY WEIGHT OF SPHAGNUM PALUSTRE AND SPHAGNUM CUSPIDATUM IN AQUEOUS CULTURES

Abstract

  The response of two Sphagnum species to copper chloride and zinc chloride was investigated in laboratory experiments which used both field shoots and axenic cultures. Both species behaved similarly. The LD50 for S. cuspidatum, estimated by regression, was 3.6 μM for copper and 33 μM for zinc, equivalent to tissue dry weights of 300 μg Cu⁺⁺ g^-1 and 2600 μg Zn⁺⁺ g^-1. The LD50 values were reduced when the supply of nutrients, particularly nitrogen, was restricted. The response of Sphagnum palustre to either metal was not changed markedly when grown in the presence of epiphytic algae.