CALLOSE IN ROOTS OF NORWAY SPRUCE (PICEA-ABIES (L.) KARST.) IS A SENSITIVE PARAMETER FOR ALUMINUM SUPPLY AT A FOREST SITE (HOGLWALD)

Under controlled environmental conditions in nutrient solution experim ents induction of non-constitutive callose in roots has been shown to be a symptom of aluminium (Al) toxicity. In the present study roots of Norway spruce were sampled from a forest site where soil conditions h ad been modified by acidic irrigation and liming (Hoglwald Experiment in Bavaria, Germany). A significant positive relationship was found be tween the callose content in short roots and the Al concentration in t he soil solution, particularly if free Al, rather than total concentra tions of soluble Al, were used for prediction. At the same sites root growth of Norway spruce was not affected by free Al concentrations in the range of 2.5 to 199 mu M Al. The results show that also under fiel d conditions a positive relationship between Al supply and callose con tent can be established. In Norway spruce callose content in roots is a much more sensitive parameter for Al supply than root growth.