Essential and non-essential elements in natural vegetation in southern Norway: contribution from different sources.

Concentrations of essential and non-essential elements in five widespread species of natural boreal vegetation were studied with respect to seasonal variation and contribution from different sources. The plant species included in the study were Betula pubescens, Sorbus aucuparia, Vaccinium myrtillus, Vaccinium uliginosum, Calluna vulgaris and Deschampsia flexuosa. Concentrations of elements essential to plants remained essentially constant or decreased slightly throughout the growing season. Concentrations of most non-essential elements increased or tended to increase on a dry mass basis from June to July as well as from July to September. The increasing trend for these elements was observed for all species except C. vulgaris. Principal component analysis (PCA) of the material indicated a common source for many of the non-essential elements; Sc, Ti, V, Ga, As, Y, Sb, lanthanides, Pb, Bi, and U, i.e. both elements presumably of geogenic origin and elements associated with trans-boundary air pollution. Uptake by plant roots appeared to be the main source of nutrient elements as well as some non-essential elements.