Influence of aluminium and nitrogen on uptake and distribution of minerals in beech roots (Fagus sylvatica)

Beech seedlings (Fagus sylvatica L. provenance Västra Torup) were grown in nutrient solution at low pH (4.2) and exposed to AlCl₃ and different concentrations of nitrogen. The effects of AlCl₃ and nitrogen on uptake of Ca²⁺ (⁴⁵Ca) and H₂PO₄^- (³²P) in roots of intact beech were studied. Crossections of roots were analyzed with respect to element concentrations, by use of Mikro-PIXE (particle induced X-ray emission). The distribution of Al, Ca, P, Mg, K, and S was analysed. The experiments were designed to evaluate the effects of aluminium on localization of elements in plant root tissue.Aluminium reduced the concentration of Ca in plants and increased that of K. High nitrogen levels in the solution further decreased the concentration of Ca in the roots. Aluminium (1.0 mM) effectively reduced the Ca²⁺ (⁴⁵Ca) uptake in short time experiments. Aluminium accumulated in high concentration (up to 500 mol/g dry weight in areas of 30×30 m²) on the root surface, epidermis and outer layers of cortex. Corresponding areas had an extremely low Ca concentration (ca 5 mol/g dry weight) which could be harmful for regulation of mineral uptake and development of roots.It is concluded that the calcium concentration in roots was reduced by aluminium. The combination with high nitrogen levels further reduced calcium changing the mineral balance which could result in deficiency conditions of calcium in the root.