Sensitivity to, and accumulation of, cadmium in Betula pendula, Picea abies, and Pinus sylvestris seedlings from different regions in Sweden

This study compared the sensitivity to, and uptake and distribution of, cadmium (Cd) in three tree species, Norway spruce (Picea abies (L.) Karst.), Scots pine (Pinus sylvestris L.), and European white birch (Betula pendula Roth), as well as different populations of these species. Seedlings of each species from three regions (southern, central, and northern parts of Sweden) were cultivated in nutrient solution and treated with varying concentrations of Cd. Sensitivity was determined by using the Weibull function on root and shoot dry weight and root length measurements. Cd uptake and translocation were analysed. The results on root sensitivity revealed that birch and spruce were the least and most sensitive species, respectively, to both the external and tissue levels of Cd. In terms of shoot sensitivity, however, birch was the only species affected by Cd, i.e., the most sensitive species. Pine and birch had similar Cd uptake, while spruce had lower uptake and translocation of Cd compared with the others. There were also differences in sensitivity within the species. The central ecotype of all species tended to be the most Cd resistant. The central ecotype of spruce and birch had the lowest Cd uptake, whereas the central ecotype of spruce and pine had the lowest translocation of Cd to the shoot.Key words: birch, cadmium, pine, sensitivity, spruce, uptake.