Nutrition-physiological responses of spruce to different levels of sulphur dioxide stress in the Erzgebirge Mountains and the Thuringian Forest, Germany

Eleven middled-aged Norway spruces (Picea abies (L.) Karst) growing in stands in the two highlands Erzgebirge Mountains and Thuringian Forest which have been subject to different SO2 deposition were investigated in a field study. Measurements were made of total element contents and the water-soluble proportions of the element contents. Low-temperature scanning-electron microscopy (LTSEM) techniques were used for structural observations. Energy dispersive microanalyses (EDX) on bulk-frozen hydrated samples led to the direct determination of element contents in the vacuoles of both the mesophyll and endodermis. Chemicals analysis of the element contents of needles revealed a significant dependency of sulphate sulphur, organic sulphur, and potassium on the SO2 pollution of the air. However, a significant influence of soil parameters on the nutrient status of the spruce growing on the different plots could nor be verified. The EDX-analyses proved that potassium is the chief ion for neutralisation of the sulphate ions at the SO2 loaded sites of Erzgebirge Mountains. To a lower extent, magnesium and, at sites rich in manganese, also manganese are involved in sulphuric acid neutralisation.