© 1992 Heron Publishing—Victoria, Canada
Influence of nitrogen fertilization on minerals, carbohydrates, amino acids and phenolic compounds in beech (Fagus sylvatica L.) leaves
Anna-Maj Balsberg Påhlsson
Department of Ecology, Plant Ecology, University of Lund, Ö. Vallgatan 14, S-223 61 Lund, Sweden / Received February 25, 1991
Summary
Beginning in 1985, plots in a 120-year-old beech (Fagus sylvatica L.) stand in the province of Scania, southern Sweden were fertilized annually with ammonium nitrate. In August 1989, leaves
from both fertilized and unfertilized trees were analyzed for mineral nutrients, soluble carbohydrates, amino acids and phenolic
compounds. Leaf concentrations of total nitrogen were increased by N fertilization. Ammonium was not detected in the leaves,
but NO3– was increased by up to 65% as a result of N fertilization. Nitrogen fertilization decreased foliar concentrations of P and
Cu, leading to a nutrient imbalance relative to N. Of the free amino acids, glutamic acid and aspartic acid predominated and,
together with glutamine and asparagine, were significantly increased by N fertilization. The concentrations of amides were
2–4 times higher in fertilized trees than in unfertilized trees. Soluble carbohydrates did not change in response to N fertilization,
but total phenolic compounds decreased markedly. The reduced concentration of phenolics may explain the greater susceptibility
to parasite attacks of trees exposed to N deposition and excess N.
