Allelopathy of the moss Hypnum plumaeforme by the production of momilactone A and B

P>Extract of soil under colonies of Hypnum plumaeforme inhibited the growth of roots and shoots of cress, lettuce, lucerne, ryegrass, timothy, Digitaria sanguinalis and Echinochloa crus-galli. Increasing the extract concentration increased the inhibition, which suggest that the soil may contain growth inhibitory substances and possess allelopathic potential. The extract of the soil under H. plumaeforme was purified and two main inhibitory substances were isolated and determined by MS and 1H- and 13C-NMR spectral data as momilactone A and B. Momilactone A and B inhibited hypocotyls and roots of cress seedlings at concentrations > 10 and 1 mu m respectively. The endogenous concentration of momilactone A and B in H. plumaeforme was 58.7 and 23.4 mu g g-1 dry weight respectively and the concentration of momilactone A and B in MS growth medium of H. plumaeforme was 4.3 and 6.4 mu g g-1 dry weight of H. plumaeforme, respectively. These results suggest that momilactone A and B were probably secreted into the medium during the incubation and momilactone A and B found in the soil under H. plumaeforme may have been released by the moss. Therefore, growth inhibitory activity of the soil under H. plumaeforme may be caused by momilactone A and B, which may act as allelopathic agents of H. plumaeforme.