Persistence of flavonoids in Cistus ladanifer soils

A lower herb richness and diversity in the presence of Cistus ladanifer is attributed to the allelochemicals exudate from its leaves and stem. The objective of the present study was to determine allelopathic activities of C. ladanifer exudates and the persistence of potential allelochemicals in soil environment. The results showed that the aglycone flavonoids degrade very slowly in the soil, remaining a very long time with no further external input. Although the amounts of aglycone flavonoids in soils are low (of the order of mu g/g soil), their high persistence may facilitate inhibition of the germination and growth of other species or an indirect effect by altering the soil's characteristics, providing a possible explanation for the phytotoxic activity attributed to C. ladanifer.