Abstract

Batatasin-III (3,3'-dihydroxy-5-methoxybibenzyl) produced by Empetrum hermaphroditum has been identified as the main metabolite responsible for the chemical interference exerted by the shrub on the surrounding vegetation in the boreal forest of northern Sweden. In earlier studies, batatasin-III has been found to be present in both soil and soil solutions. However, to understand the actual mechanisms by which batatasin-III may interact, we need to know more about the fate and behaviour of the compound in soil. In order to achieve this, we firstly evaluated the efficiency of different extraction methods in recovering batatasin-III from Empetrum humus and found that the highest yield was obtained using ethyl acetate (6.57 +/- 20 mu g g(-1) HDM, least square mean +/- SE). In contrast, no detectable amounts of batatasin-III were obtained when extracting the humus with distilled water, 0.125 M citric acid or 0.05 M NaOH. Secondly, we performed a series of experiments in which the recovery of batatasin-III was determined from humus samples exposed to different treatments. In summary, the recovery of batatasin-III was found to be initially strongly dependent on humus type (i.e. humus collected from under a cover of Empetrum, Vaccinium or forest herbs) as well as the temperature and the length of the incubation period. The amount of recovered batatasin-III was in general highest from the Empetrum humus and lowest from the herb humus, contrary to our hypothesis that microorganisms might be better adapted to batatasin-III in humus of the Empetrum origin than in humus of other origin. Regardless of humus type, the recovery was generally higher at + 2 degrees C than at + 18 degrees C suggesting that microbial degradation of batatasin-III did occur. However, when the recovery of batatasin-III from sterile and non-sterile humus was compared, microbial degradation was found to be of minor importance. In addition, no phenolic degradation products of batatasin-III were detected after batatasin-III had been added to non-sterile humus. The obtained results suggest that batatasin-III, when released into humus, becomes physically trapped by organic matter and metabolized by soil microbes to a less extent. (c) 2004 Elsevier Ltd. All rights reserved

Published in

Biochemical Systematics and Ecology
2005, Volume: 33, number: 4, pages: 385-407
Publisher: PERGAMON-ELSEVIER SCIENCE LTD

SLU Authors

• Nilsson Hegethorn, Marie-Charlotte

  • Department of Forest Vegetation Ecology, Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Forest Science


Publication identifier

DOI: https://doi.org/10.1016/j.bse.2004.08.007

Permanent link to this page (URI)

https://res.slu.se/id/publ/6064