Allelopathy of Aspergillus japonicus on crops

The seeds of some dicotyledons fail to germinate and grow well when contami nated by Aspergillus japonicus Saito. One strain of A. japonicus isolated f rom the seeds of contaminated rape (Brassica campestris L.) inhibited the s eedling growth of rape and radish (Raphanus sativus L.) when the fungus was directly inoculated on the seed surface. Metabolites released from the fun gus inhibited the seedling germination and seedling growth of rape and radi sh. The culture filtrate and mycelium acetone (C3H6O) extract inhibited the seedling growth of rape. The major allelochemical of A. japonicus was iden tified by spectroscopic methods as secalonic acid F (SAF), Bioassays showed that SAF at concentration 0.038 mM significantly inhibited the seedling gr owth of several crops.