REACTION OF MYCORRHIZAL AND NONMYCORRHIZAL SCOTS PINE FINE ROOTS ALONG A DEPOSITION GRADIENT OF AIR-POLLUTANTS IN EASTERN GERMANY

Based on an ecosystematic approach within the comprehensive SANA (Rege neration of the atmosphere above the new federal states) -project the influence of industrial air pollutants (SO2, NOx, alkaline fly ashes) on the vitality of mycorrhizae, mycorrhizal frequency, and on paramete rs of root growth such as root biomass and necromass and distribution of different root classes in the soil horizons was investigated. The s tudies were conducted in three comparable Scots pine ecosystems in eas tern Germany which were exposed to different deposition loads of air p ollutants during the time of the former German Democratic Republic. Si te specific differences were obtained for all parameters investigated. The reference plot Neuglobsow (background deposition) revealed the hi ghest number of vital mycorrhizae, highest mycorrhizal frequency, and largest biomass of finest roots in the humus layer. At the impact-site s Roesa and Taura (heavy acid moderate deposition) located near Halle/ Bitterfeld and Leipzig, the number of vital mycorrhizae was reduced an d the life-span of mycorrhizae of reduced vitality was elongated. Fine st root biomass and necromass of the humus layer were also lower at th ese plots as compared to Neuglobsow. At Neuglobsow a higher turnover o f mycorrhizae and finest roots of the humus layer is assumed. The redu ced growth of mycorrhizal and non-mycorrhizal finest roots at the two pollution impacted sites Roesa and Taura is seen as an adaptation mech anism of the root system to high nutrient inputs.