Influence of aluminium on biomass, nutrients, soluble carbohydrates and phenols in beech (Fagus sylvatica)

The effects of aluminium on biomass, nutrients and soluble carbohydrates and phenols were studied in beech ( Fagus sylvatica L.) seedlings. After germination, seedlings with cotyledons and the buds of the first leaf-pair developed, were preconditioned for two weeks and then grown for 31 days in nutrient solutions containing 0.1, 0.5, 1.0 or 2.0 m M A1C1₃. Aluminium did not affect the dry weights of roots but at Al concentrations ≥ 1.0 m M the development of the terminal shoot above the first leaf pair, was reduced by 80% or more. The concentrations of most nutrients (P, Ca, Mg, Zn, Cu) in the plant tissues decreased strongly even at the lowest Al levels, but K increased in the shoots. The tissue concentration of N was not affected of Al. but the distribution between the organs was changed to a higher content of N in the roots. At ≥1.0 m M Al the concentrations of starch in both the shoots and the roots were significantly increased, and at ≥ 0.5 m M the roots contained more of total phenols than untreated seedlings. The elevated concentrations and contents of starch and phenols in the seedlings may partly be related to the reduced shoot growth. The observed effects of Al were marked already at Al levels found in soil waters from beech forests in southern Sweden.