Phosphate status and acid phosphatase activity in soil and ectomycorrhizas in two mature stands of scots pine (Pinus sylvestris L.) exposed to different levels of anthropogenic pollution

Abstract

The relations between anthropogenic environmental pollution and the level of inorganic phosphorus in soil, enzyme activities of extracellular soil acid phosphatase and the surface acid phosphatase of excised ectomycorrhizas of Scots pine (Pinus sylvestris L.) were studied. Soil and root samples were taken from two Scots pine stands in central Poland: a polluted site exposed to long-term pollution from a steelworks and the city of Warsaw and a reference plot (control) free from direct impact of pollution. The polluted site was characterised by high concentration of trace elements (Cd, Pb, Cu, Zn, Mn, Cr) and low level of inorganic phosphate in soil. This site had significantly lower enzyme activities of soil acid phosphatase (0.54 µmoles p-nitrophenol released g^-1 dry weight h^-1) and surface acid phosphatase of pine ectomycorrhizas (3.37 µmoles p-nitrophenol released g^-1 fresh weight h^-1) than the control site (1.36 µmoles p-nitrophenol released g^-1 dry weight h^-1 and 12.46 µmoles p-nitrophenol released g^-1 fresh weight h^-1, respectively). The levels of phosphate, carbon and nitrogen in pine fine roots were also analysed. Low concentrations of P0₄-P and high N: P ratio in pine fine roots from polluted site were found. The results suggest that soil pollutants may have a negative effect on the extracellular acid phosphatase of soil and Scots pine ectomycorrhizas and on the phosphorus status in fine roots of the plant.