Allelopathic activity of coriander (coriandrum sativum L.)

In recent years there has been increased interest about the allelopathic effects of plant extracts used as bioherbicides, in order to manage weeds with a decreasing use of herbicides. An interesting crop, from an allelopathic point of view, is coriander ( Coriandrum sativum L.), a medicinal plant member of Apiaceae family. The aim of this study was to evaluate the allelopathic activity of coriander against a possible succeeding crop, like wheat ( Triticum aestivum L.), and against some weeds, like Lolium multiflorum Lam., Sinapis alba L. and Amaranthus retroflexus L., ubiquitous in the Mediterranean agroecosystems. In Petri dish bioassays, seeds of above-mentioned species were treated with 0, 2.5, 5, 10, 17.5, 25% w/v concentrations of aqueous extracts from leaves, stems and roots of coriander at flowering and maturity growth stage. The ranking among different extracts based on their allelopathic effects was: leaves extract > stems extract > roots extract. The allelopathic activity of coriander at maturity stage decreased with respect to that at flowering stage. Total polyphenols, flavonoids and phenolic acids were involved in the allelopathic activity of coriander. The aqueous extracts from aerial biomass of coriander inhibited the seed germination of weeds, but not that of T. aestivum . This research has provided interesting scientific insights into the allelopathic activity of coriander in weed management, however, other aspects need to be further investigated.