LOCALIZATION OF ALUMINUM IN THE ROOTS OF NORWAY SPRUCE [PICEA-ABIES (L) KARST] INOCULATED WITH PAXILLUS-INVOLUTUS FR

Norway spruce [Picea abies (L.) Karst.] seed lots from populations growing on acid soil in the Black Forest (BF), and from a calcareous soil in the Schwabische Alb (SA), West Germany, were grown in perlite and treated with 0 and 6 mM Al. Some of the plants were inoculated with the fungus Paxillus involutus Fr., while some were not. Fungus was associated with the roots of the inoculated plants, but mycorrhizas did not form. Mineral element distribution in the roots was investigated using X-ray microanalysis of freeze substituted sections in TEM. Seven elements were detected: aluminium, silicon, phosphorus, sulphur, chlorine, potassium, and calcium. Aluminium was almost entirely confined to the cortical cell walls, and was not detectable inside the endodermis. The presence of P. involutus significantly increased aluminium concentrations in the cortical cell walls of both seed lots, while silicon concentrations in the aluminium-tolerant (BF) plants increased in response to aluminium treatment.