Peroxidase activity as an indicator of pollution stress in the fine roots of Pinus sylvestris

Peroxidase activity was determined in the fine roots and mycorrhizae of Scots pine (Pinus sylvestris L.) in order to evaluate the suitability of this parameter as an indicator of stress caused by a long-term deposition of urban air pollutants. 3,3'-Dimethoxybenzidine and methylaminophenol were used as substrates. Peroxidase activity (3,3′-dimethoxybenzidine as a substrate) of the fine roots collected in autumn averaged 7.23 A min^?1 g^?1 root fresh weight in controls and 40.79 A min^?1 g^?1 in the most polluted pine stands, activities in the samples from June being distinctly lower. Peroxidase activity correlated positively with total N (p<0.05), total S (p<0.01), Cu (p<0.01) and NH₄ (p<0.05) in the mor humus layer. Significant negative correlations were found with the total number of root tips and the number of well-developed mycorrhizae per unit soil volume. Methylaminophenol gave lower activities and those did not correlate with either pollution or mycorrhizal parameters.