INSTYTUT DENDROLOGII

Abstract:Ectomycorrhizas of Scots pine (Pinus sylvestris L.) and beech (Fagus sylvatica L.) were sampled in a mature forest ecosystem exposed for more than 40 years to moderate levels of gaseous and dust pollutants. Soil of the forest site was characterised by low pH and accumulation of heavy metals (Pb, Mn, Zn, Cu, Cd, and Fe). Mycorrhizal vitality and enzyme activity of the root-surface and soil acid phosphatase (AcPase) were studied at 17 measurement points (0-5 cm soil depth) in relation to the content of inorganic phosphate (P₂O₅) and aluminium ions (Al³⁺) in soil. The concentration of essential nutrients (C, N, P, Ca, Mg) and the ratios Ca/Al, Mg/Al and N/P were analysed in fine roots. High concentration of Al³⁺ in soil (40-118 meq kg^-1) and low level of Pi (12-44 mg P₂O₅ kg^-1) were accompanied by high activity of the root-surface AcPase of pine and beech mycorrhizas (25-67 and 33-86 µmol pNP g^-1 fresh weight h^-1, respectively) and soil AcPase (6.8-22.4 µmol pNP g^-1 dry weight h^-1). The results indicate that tree fine roots are undoubtedly under stress that is evidenced by a disturbance in P uptake and accumulation. However, the high vitality mycorrhizas and high Ca/Al ratio in fine roots suggest, that the defence mechanisms of mycorrhizas and the rhizosphere are still able to ameliorate the influence of anthropogenic pollution.

Additional key words: acid phosphatase, fluorescein diacetate, soil, Fagus sylvatica, Pinus sylvestris, root anatomy