RESPONSE OF EUROPEAN CHESTNUT TO VARYING CALCIUM ALUMINUM RATIOS/

The response of European chestnut (Castanea sativa Mill.) to varying C a/Al ratios of 10, 1, 0.1, and control (no Al added) in nutrient solut ions with constant concentrations of 1 mmol L(-1) Ca was investigated in a greenhouse experiment. The various Ca/Al ratios did not cause a s ignificant effect on biomasses of roots, stems, shoots, and total plan ts. At a Ca/Al ratio of 0.1, however, a lower number of leaves with le ngths >15 cm, a decreased biomass of leaves, an increased root/shoot r atio, and a decreased fine root ratio (roots with diameters <1 mm/root with diameters 1-2 mm) were observed. Elemental analyses of Al and ba se nutrient cations in roots and leaves revealed that increased Al con centrations reduced the uptake of es and Mg, but not the uptake of Ii. Aluminum concentrations mere much higher in fine roots than in leaves , clearly indicating that only a minor amount of root Al was transport ed into leaves, This finding was supported by EDX analyses and microsc opic data, where Al in fine roots was mainly detected in epidermal and cortical cells, but to a lesser extent in cells of the stele. Tile co mparison of the results from the greenhouse experiment with field data from southern Switzerland suggests that there is no current risk orig inating from low Ca/Al ratio in the soil solution for European chestnu t at the field site.