Phenolic metabolites of ecological significance in Empetrum hermaphroditum leaves and associated humus

Condensed tannins, phenolic acids and batatasin-III were measured in green and senescent leaves of the dwarf Ericaceous shrub Empetrum hermaphroditum Hagerup collected at three boreal sites in northern Sweden. The influence of this shrub on the composition of soil phenolics was estimated through phenolic analysis of leaves and associated humus. Green leaves contained large amounts of batatasin-III (maximum value of 13.8 mg g(-)1 dry weight at one site) and condensed tannins (5.5 mg g(-1)), but lesser amounts of phenolic acids (1.7 mg g(-1)). All these compounds were also found in brown senescing leaves but at lower concentrations. Humus under E. hermaphroditum contained 1 mu g g(-1) of water-soluble batatasin-III and about 2 mu g g(-1) of water-soluble phenolic acids. When E. hermaphroditum was absent, batatasin-III was not recovered in humus and the concentration of phenolic acids was found to be much lower. We conclude that batatasin-III and some related metabolites (phenolic acids) could influence ecosystem function, because of their durability in E. hermaphroditum litter and humus.